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General Discussions => The Lab => Topic started by: Soeren_DK on December 02, 2009, 03:34:06 AM

Title: Bo Hansen DI layout
Post by: Soeren_DK on December 02, 2009, 03:34:06 AM
(http://www.silentarts.de/DIY/BoDI/BoDI-rev2PCB-01.gif)(http://www.silentarts.de/DIY/BoDI/BoDI-rev2PCB-03.gif)
Bo Hansen's DI page:
http://www.hansenaudio.se/techpage.htm#active%20DI-box,%20my%20work%20horse%20from%201975
and the schematic is here: http://www.hansenaudio.se/Active%20DI%20box%201975.jpg

Boards available here:
From June 2015, Volker is the new supplier of PCBs.
https://groupdiy.com/index.php?topic=39570.msg488632#msg488632 (https://groupdiy.com/index.php?topic=39570.msg488632#msg488632)

Shopping list:
US: http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=12eddc2712
http://benlindell.com/diy/Bo-Hansen-DI-BOM.pdf (made by benlindell)

EU: http://www.mentol.dk/diy/bohansen/BOM - Diyfanatic - bo DI.xlsx (http://www.mentol.dk/diy/bohansen/BOM - Diyfanatic - bo DI.xlsx) (made by diyfanatic)

Help:
TRANSISTOR CHOICE (http://www.groupdiy.com/index.php?topic=36569.msg484228#msg484228)
HAUFE TRAFO BUY (http://www.groupdiy.com/index.php?topic=39570.0)
MAKING PAD MOD (http://www.groupdiy.com/index.php?topic=36569.msg467685#msg467685)


Self-etching papers:
http://www.mentol.dk/diy/bohansen/bohansen.pdf
http://www.mentol.dk/diy/bohansen/silkscreen.pdf

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on December 02, 2009, 03:34:41 AM
The behind
Title: Re: Bo Hansén DI layout
Post by: zebra50 on December 02, 2009, 04:46:44 AM
Nice idea!

How hard would it be to make this accept alternative transformers? For example a Sowter as noted on Bo's web page, or an OEP like on the Gyraf G9?

Title: Re: Bo Hansén DI layout
Post by: rotation on December 02, 2009, 06:09:28 AM
Nice idea!

How hard would it be to make this accept alternative transformers? For example a Sowter as noted on Bo's web page, or an OEP like on the Gyraf G9?



This was my first thought when i've seen the layout. Another good thing to do would be making layout a little smaller. That wouldn't be hard if he will do rerouting to accept other transformers.

Miha
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on December 02, 2009, 06:36:38 AM
Nice idea!

How hard would it be to make this accept alternative transformers? For example a Sowter as noted on Bo's web page, or an OEP like on the Gyraf G9?


I have looked on the Sowter but I can't figure out the right spacing dimension.
http://www.sowter.co.uk/specs/3678.htm
(http://www.sowter.co.uk/sizepics.htg/sizede.jpg)
These dimension dosen't fit any standards. As opposed to Lundahl http://www.lundahl.se/pdfs/datash/1538_8xl.pdf

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: stitch-o on December 02, 2009, 09:13:19 AM
Id love to make a rack of 4 of these!
Title: Re: Bo Hansén DI layout
Post by: Davo on December 02, 2009, 12:20:50 PM
Nice one Soeren!!  My favorite DI ;D
Title: Re: Bo Hansén DI layout
Post by: mitsos on December 02, 2009, 01:31:55 PM
Very good idea! What size is the PCB?   Also think other trafo options would be good... maybe a cinemag footprint... that would give the choice of Cinemag, Jensen and Altran trafos, including the EA2622, though I don't know how any of these would work in the circuit... Is 1:5 the ideal ratio here?
cheers!
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on December 02, 2009, 01:49:36 PM
The board is 80 x 50mm so 4 of them will fit a EURO card. Do you have some info about the cinemag footprint?
I don't have knowledge to tell if the 1:5 ratio is ideal or not.

Cheers
Soren
 
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on December 02, 2009, 01:59:53 PM
Sören,

I send you a e-mail 2009-11-16 about the OEP pc-board alternative, have you seen that ??

Please, before you done modifications on the PC-bord, and spread it out for DIY, ask me, so I can check it out first, I will be glad to do that for you.

When you change transformer, it is very important that the impedance, ratio and phase configuration will be right.

Note, that the Lundahl LL-1538 is optimized for best headroom when you load the DI-box XLR output around 1 - 2 kohm.
Maybee with other transformers, the  3,9k resistor must be change for same result.

--Bo
Title: Re: Bo Hansén DI layout
Post by: mitsos on December 02, 2009, 02:24:06 PM
It may not be the ratio, but look at the CM75101 as that also has dual primaries (secondaries in this case, since it is reversed), and is the same footprint as the EA2622 and some Altrans and smaller Jensens. While you're at it, not to give you too many headaches, but maybe a jumper to choose series/parallel primaries (secondaries here) might also make it more universally accepting of PC mount trafos, although, in the end, people could just use leaded ones and hook them up any way they want. 

The OEP is also a good inexpensive option and I believe all three footprints can be made to work together if you're into puzzles.

@Bo, can you explain the bit about the 3K9 resistor? Is that biasing the transistor?
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on December 02, 2009, 02:25:01 PM
I send you a e-mail 2009-11-16 about the OEP pc-board alternative, have you seen that ??

I haven't received that mail. The latest mail from you is the one from October 28.


Please, before you done modifications on the PC-bord, and spread it out for DIY, ask me, so I can check it out first, I will be glad to do that for you.

Of couse. I wouldn't put your name on anything you haven't seen, checked and approved first.

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on December 02, 2009, 02:56:34 PM
Sören,

It was on this gmail address you have sent to me before, have you change adress ?? PM or e-mail me, and i will send you a copy.

Mitsos,

The 3,9 kohm resistor are the emitter resistor for the last PNP emitter follower transistor, and it will set the current trough this transistor, and also the total current draw from the phantom power feed.

So you must choose a good compromise between highest internal B+ voltage and the transformer feed capacity.

In the Lundahl LL-1538 case it was approx. 3,5mA total, and I also get 24 volt as B+, and this is a nice compromice.

--Bo
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on December 02, 2009, 03:06:19 PM
It was on this gmail address you have sent to me before, have you change adress ?? PM or e-mail me, and i will send you a copy.

You got mail :D ;D ;D

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on December 02, 2009, 03:16:48 PM
nice. I will toss away my layout I started :-\ :o ;D
to confuse a little more, there is a nice Haufe transformer, designed to replace the LL1538 ...
we will use it as an option in the JensAmp, since (even it is Haufe) the price is much lower

Soren, if you are interested in adding this footprint (very easy) I will send you some details
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on December 02, 2009, 03:55:29 PM
Silent:arts,

Very Interesting, both Haufe and Pikatron have done nice transformer since long time ago.

Please can you PM or email me information about this LL1538 replacemaent from Haufe. (or maybee in a repaly here on the forum)

--Bo
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on December 02, 2009, 04:09:21 PM
@Bo
Great, will you look at the info from Silent and send me some info about it afterwards.

What drill size is common used for resistors, diodes etc.. I have used the same size for all holes (0,80mm) except the "input", "amps out" "ground", XLR out (1,00mm) and the trafo (1,50mm)

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on December 02, 2009, 05:07:31 PM
Bo, mailed you. the datasheet is german only, let me know if you need more information or a sample.

Soren, 0,8mm is fine for resistors (<1W), for 1N4XXX Diodes (DO41) I use 1mm.
the transformers holes are very different, you have to refer to the datasheets.
Title: Re: Bo Hansén DI layout
Post by: rotation on December 02, 2009, 05:50:26 PM
nice. I will toss away my layout I started :-\ :o ;D
to confuse a little more, there is a nice Haufe transformer, designed to replace the LL1538 ...
we will use it as an option in the JensAmp, since (even it is Haufe) the price is much lower

Soren, if you are interested in adding this footprint (very easy) I will send you some details

Can you tell us more about this transformer? Can we buy it or it was only a batch for certain people?

Miha
Title: Re: Bo Hansén DI layout
Post by: detonator on December 03, 2009, 04:05:21 PM
Can you tell us more about this transformer? Can we buy it or it was only a batch for certain people?
please check http://www.lundahl.se/ (http://www.lundahl.se/)
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on December 07, 2009, 05:41:55 AM
The latest design.
Title: Re: Bo Hansén DI layout
Post by: audiox on December 07, 2009, 10:13:58 AM
You could fit those components on much smaller board area. Easier to place it in an enclosure and it could have some (minimal) effect in noise pickup too.
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on December 07, 2009, 11:21:40 AM
Bo, transformer is on its way :)
Title: Re: Bo Hansén DI layout
Post by: 3nity on December 07, 2009, 12:19:33 PM
I have a layout done for this and i used Cinemag, Lundhalland OEP iron..
3.5" x 2" let me know anything..
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on December 08, 2009, 02:43:57 PM
I have a layout done for this and i used Cinemag, Lundhalland OEP iron..
3.5" x 2" let me know anything..
Do you have some drawings you can upload here?

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on December 08, 2009, 02:50:59 PM
Audiox,

I think it is a great layout Soren have done, and the size is very convenient for DIY, (some of the builders is maybe not so practised with small pc-board and components)

And you must still have a stable box that fit a XLR and two jacks, so you will have the space inside.

No problem with noise pick-up, if you use a metall case, that you shall do in this case.


Silent:arts,

Thanks a lot,
I will test it and get back to you with the result.

--Bo
Title: Re: Bo Hansén DI layout
Post by: 3nity on December 08, 2009, 11:24:25 PM
(http://www.twin-x.com/groupdiy/albums/userpics/normal_PCBBH.JPG)

Iron its OEP/Lundhall/Cinemag.
C1 i let some place for Wimas 10uf.

Dimensions are: 3.5" x  2"..

I havent had time or funds to test it yet..
Title: Re: Bo Hansén DI layout
Post by: flaheu on December 09, 2009, 06:17:32 AM
Hi guys,

All this is interesting for sure.
I've done several of these with 1:6.45 OEP tx, and it sounds really great.
I have also put a small LED for "power on" on mine, it was a tiny led (1.8mm diameter with a high value resistor for low consumption)
...may be a nice addition.............. ;)
Title: Re: Bo Hansén DI layout
Post by: rotation on December 09, 2009, 06:54:32 AM

Yeah, OEP sounds interesting and nicely colored, but it will not take VERY high levels. I also tried it with Cinemag CMMI-7C, it beats any expensive Radial DI etc.
This is serious design with very good sound.

Thanks a lot Bo, my friends and me really enjoyed this project!

Miha
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on December 09, 2009, 06:59:56 AM
...
I have also put a small LED for "power on" on mine, it was a tiny led (1.8mm diameter with a high value resistor for low consumption)
...may be a nice addition.............. ;)
looking at Soeren_DKs latest design I can see a LED  :D
Title: Re: Bo Hansén DI layout
Post by: jensenmann on December 09, 2009, 01:36:59 PM
I did a pair of these DIs on perfboard with Haufe iron. These DIs won since then every shootout against any highpriced brand (lowpriced either). Definitely a wonderful tool and worth every cent. It´d even be worth to have them in a 51x version.  ;)
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on December 09, 2009, 01:50:02 PM
Jens, which Haufe iron did you use?
a 51x version sounds like a good idea btw  :-*
Title: Re: Bo Hansén DI layout
Post by: flaheu on December 10, 2009, 04:08:37 AM
 ;) my bad for the LED, didn't see it
Title: Re: Bo Hansén DI layout
Post by: jensenmann on December 10, 2009, 07:09:08 AM
It´s a Haufe T5223 4:1
Datasheet is at kubi´s page
CJ did hack one of these and stated that it´s one of the best transformers he ever took apart.
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on December 10, 2009, 02:43:02 PM
Flaheu,

If you look on version 4-2 (replay #20) below the 100 uF electrolytic, with text "LED or Link".

I use a LED connected in serial with the voltage feed, after the two 6,8k phantom resistors.
In this case, the LED don´t steal any additional current from the phantom line.
You get only a small voltage drop, (approx. 1,5 volt with a red LED) so you not reduce the emitterfollower headroom hardly noticeable.
(compare with a normal connected LED with a minimum current (approx. 2 mA/10k limit resistor) and you get maybe 6 volt drop)

--Bo
Title: Re: Bo Hansén DI layout
Post by: Moses on December 11, 2009, 05:29:35 AM
Jensenmann,

Where did you pick up your Haufe iron? Their website seems to indicate they only do custom jobs, although my German (and Google translator's!) is pretty flawed so Im more than likely wrong on that!!

Mo
Title: Re: Bo Hansén DI layout
Post by: wolfgang on December 15, 2009, 12:58:41 PM
Quote
nice. I will toss away my layout I started   
to confuse a little more, there is a nice Haufe transformer, designed to replace the LL1538 ...
we will use it as an option in the JensAmp, since (even it is Haufe) the price is much lower

To Silentarts:

Do you mind sharing some infos on this transformer? Partnumber, specs and where it is available?

I could not find any haufe distributor on the web and also no model description on their own website.

Thanks,
Wolfgang

Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on December 15, 2009, 03:15:23 PM
To Silentarts:
Do you mind sharing some infos on this transformer? Partnumber, specs and where it is available?
I could not find any haufe distributor on the web and also no model description on their own website.
Well, we will wait for Bo if the sample I shipped to him reacts positive in his circuit design.

You won't find any Haufe distributor, and they only do build to order.
which makes a one off very expensive (my RK204 was EUR 120+ if I recall correctly).
If Bo is fine with this transformer (not the RK204, it is a ST), and the PCBs are available, I will think of buying a larger quantity and have them in stock.

since they are not available & untested by Bo yet it doesn't make sense to talk about the specs etc
Title: Re: Bo Hansén DI layout
Post by: wolfgang on December 15, 2009, 03:30:29 PM
Thank you for clearing this up!

Ao you will stock them at you webshop?! Very nice!
When will the shop be online btw? I am very curious about it!


regards,
Wolfgang
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on December 15, 2009, 04:10:32 PM
Ao you will stock them at you webshop?! Very nice!
When will the shop be online btw? I am very curious about it!
plans for beeing online: not in 2009 anymore
for the trafos and stock yes, but first we need available PCBs ;D
to be back on topic :)
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on December 15, 2009, 04:39:04 PM
 :)
I'm planing making a proto for Bo in the christmas vacation and when he has tested it I'm sending the gerbers for Gustav.

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on December 16, 2009, 04:42:19 PM
Between Christmas/New Year I will try to do a transformer test/evaluation and compare Lundahl, Haufe and OEP in the DI-Box electronics.

But Just now I wait for a sample of OEP A262A3E from UK, so I will start when I receive that.

--Bo
Title: Re: Bo Hansén DI layout
Post by: lcaudio on December 17, 2009, 06:01:41 PM
This will be really cool, i would definitely buy some pcbs! I did my first build from Bo's schematic and it sounds great, but it seems to have pretty low gain. Is that the nature of this di or did I possibly do something wrong? Thanks.
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on December 19, 2009, 10:33:52 AM
Icaudio,

If everything is ok, and you have connected the transformer fore 5:1 configuration you shall have around 15 dB loss from instrument input to XLR balanced out. (no loss, 1:1 from instrument input to monitor amp out)

Because you use a microphone transformer backwards you get "loss" negative gain, and a 1:5 ratio transformer have approx. 15 dB step-up gain, or loss used backwards.

You want loss in a DI-box, because the level from a guitar or bass, (after a 1:1 impedance converting) are to high to match a console microphone input.

I will guess that mostly of active DI-boxes on the market have approx. 5-15 dB loss, and passive have approx. 20-30 dB loss.

If you after all need more gain, use the 2,5:1 configuaration instead for the 5:1 configuraton on the Lundahl LL-1538 transformer and you get only 10 dB loss instead for 15 dB, and have 5 dB more gain out from the DI-box.
(but the best transformer match in this circuit are the 5:1 configuration)

--Bo
Title: Re: Bo Hansén DI layout
Post by: lcaudio on December 19, 2009, 09:01:41 PM
Thanks for responding Bo. That was a much more involved response than i had anticipated and appreciate it greatly. A lot of great information! I use the DI mainly for live use and it does sound great. I was only conerned that I may have wired something wrong because it was seemingly lower gain than other actives i've used. I don't think i'll alter for more gain and stick to your design. I'll also have something to compare it to once the PCB's are released to the community. Thanks for your great design, it was a pleasure to build.


logan



Icaudio,

If everything is ok, and you have connected the transformer fore 5:1 configuration you shall have around 15 dB loss from instrument input to XLR balanced out. (no loss, 1:1 from instrument input to monitor amp out)

Because you use a microphone transformer backwards you get "loss" negative gain, and a 1:5 ratio transformer have approx. 15 dB step-up gain, or loss used backwards.

You want loss in a DI-box, because the level from a guitar or bass, (after a 1:1 impedance converting) are to high to match a console microphone input.

I will guess that mostly of active DI-boxes on the market have approx. 5-15 dB loss, and passive have approx. 20-30 dB loss.

If you after all need more gain, use the 2,5:1 configuaration instead for the 5:1 configuraton on the Lundahl LL-1538 transformer and you get only 10 dB loss instead for 15 dB, and have 5 dB more gain out from the DI-box.
(but the best transformer match in this circuit are the 5:1 configuration)

--Bo
Title: Re: Bo Hansén DI layout
Post by: justanalogue on December 20, 2009, 12:54:04 PM
Very nice work gentlemen!!!

Ready for PCB's.

Willem.
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on December 29, 2009, 08:59:53 PM
Hi  Bo,  Soren and Guys !!

Exelent work!!
I´m thinking to put together in a single box the Bo hansen DI and the Green PREamp. I create a new topic about this here http://www.groupdiy.com/index.php?topic=36987.0    :)  I love to make my own PCBs (with Lazer Print and the transfer method on a virgin copper PCB) because the DIY thread feels much "ARTESANAL"¡¡¡¡.

Soren, if it is posibless, please, post (upload) the Copper Layout (only botton layout) of your Bo Hansen´s PCB??? Only the cooper tracks in black, ready to transfer like Gyraf´s PCBs proyects.  It´s only for personal use and for the people that like to make the own PCBs.
;)
Thanks for the patience I am beginner.

Juanjo

Here is my first PCB, Its the KROC´s PCB (Kev Ross Opto Compressor, Dual compressor based on LA-4) I´m working in this proyect, while I wait for the arrival of the parts that I bought to make the Kroc, I am making the Green MKII V14 PCBs.

The copper botton side

(http://),
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on December 29, 2009, 09:15:56 PM
and this is the Top Side or Components side..... mmmm How I can insert the images directly!!!!!!! without use the attach form! I am a bad "cyberboy" jeje
Title: Re: Bo Hansén DI layout
Post by: lcaudio on January 17, 2010, 05:34:19 PM
Any progress on this?  ;D
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on January 18, 2010, 03:05:31 AM
Any progress on this?  ;D
I don't want to be leaky, but I know Bo did some transformer testings over the weekend :D
Title: Re: Bo Hansén DI layout
Post by: ChrisPbass on January 18, 2010, 08:39:41 AM
Excellent news, looking forward to this.   :)

Glad I put off buying any 'off the shelf' brands as I've heard great things about this design.

Chris
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on January 18, 2010, 10:31:57 AM
I had to make some test pcb for Bo in the christmas holliday but the plans went totally wrong but thats an other story. I'm trying to get it done by the end of this week.
Sorry for the delay

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: TheGuitarist on January 20, 2010, 04:17:57 AM
I know active and passive DIs have their advantages, but is this design a bridge? Or just another good one.
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on January 20, 2010, 08:13:10 AM
Anyone have the time to etch a proto pcb for Bo so he can test the design before we make a bunch of them.
I will provide the layout in a pdf filer here?

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on January 20, 2010, 08:30:27 AM
contact Lukas (http://www.groupdiy.com/index.php?topic=37108.msg456223#msg456223)
I will pay for it.
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on January 20, 2010, 10:35:38 AM
Hi,
a PDf file is a good idea thanks for that, so the people that  they want can etch their own pcb, in the other hand the option to buy a profesional pcb , helps especially when the guys dont have time. Its a good contribution. ;)

thanks Soeren
regards
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on January 21, 2010, 04:18:59 PM
contact Lukas (http://www.groupdiy.com/index.php?topic=37108.msg456223#msg456223)
I will pay for it.
I have send an email to Lukas but I will of cause pay for it. Thanks for your kindness but you don't have to pay. ;) ;) ;) ;)


The latest design:
http://www.mentol.dk/diy/bohansen/print.pdf (http://www.mentol.dk/diy/bohansen/print.pdf)
http://www.mentol.dk/diy/bohansen/pcb.JPG (http://www.mentol.dk/diy/bohansen/pcb.JPG)
http://www.mentol.dk/diy/bohansen/silk.JPG (http://www.mentol.dk/diy/bohansen/silk.JPG)

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on January 22, 2010, 02:03:55 PM
Thanks !!!!!!
Muchas Gracias!!!!! Soren, Bo, Torben

I will etch the pcb on this weekend and I can test it , but I don´t have a tranfo right now, I can buy a OEP today but I think that the transfo. will arrive to Ecuador in 4 weeks.


again thanks for
a great contribution

Best regards
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on January 24, 2010, 03:22:15 PM
Thanks !!!!!!
Muchas Gracias!!!!! Soren, Bo, Torben

I will etch the pcb on this weekend and I can test it , but I don´t have a tranfo right now, I can buy a OEP today but I think that the transfo. will arrive to Ecuador in 4 weeks.


again thanks for
a great contribution

Best regards
:o  ;) ;) ;) ;)
I look forward to hear about your experience :) :)

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on January 24, 2010, 09:27:11 PM
Hi Soren!!

I don´t have a lot experience but I can etch the PCB and try it :) , so if You or someone want test the layout  I can etch and send a PCB  ;).

Best regards
Juanjo
Title: Re: Bo Hansén DI layout
Post by: llanafreak44 on February 05, 2010, 02:48:28 PM
This is very interesting! I'm an electronics noob, so a predone board seems perfect. I'm keeping this topic bookmarked ;).


A question though, I've read that the Lundahl trannies aren't distributed in the US. Would an alternative tranny work on the board?
Title: Re: Bo Hansén DI layout
Post by: dissonantstring on February 05, 2010, 03:13:57 PM
A question though, I've read that the Lundahl trannies aren't distributed in the US. Would an alternative tranny work on the board?

actually, one of our fine members (Kevin C.) is the US distributor of lundahl transformers.
http://www.kandkaudio.com/ (http://www.kandkaudio.com/)

there are many alternatives, you just have to find the right one and it depends on your taste.
regards,
grant
Title: Re: Bo Hansén DI layout
Post by: llanafreak44 on February 05, 2010, 03:17:55 PM
Excellent, thank you for the link!


I might have missed it, but are these PCB's being made for purpose of DIY printing or for distribution?
Title: Re: Bo Hansén DI layout
Post by: mulletchuck on February 22, 2010, 05:00:07 AM
has this PCB been made available for purchase?    this looks like a great first project!
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on February 22, 2010, 05:13:55 AM
has this PCB been made available for purchase?    this looks like a great first project!
Not yet. We are waiting for Bo to test this pcb layout.

cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on February 22, 2010, 02:28:04 PM
Sorry guy's for the delay, to much incoming audio gear for service, to less time for funny things as this project.

Yeas, I have assamble the pc-cards and test them with all three transformers, and it works perfect.
Only some small practical things to take care of, as some components that must have more space, and som holes that must be bigger.

I will send Sören a mail regrdings this very soon.

I have also a nice metal box that fit great, that I will assamble with pc-card and all connectors, so it will be a complete ready DI-Box.
Picture will comming up here later on.

--Bo
Title: Re: Bo Hansén DI layout
Post by: justanalogue on February 22, 2010, 04:59:38 PM
Big thumbs up for Bo and Sören!

Really want to build a few of these for the studio, need good " workhorses".
Bo, any idea of transformers of a Lyrec 532 will do the job?
Know from Jakob Erkland these are Jorgen Schou ones.

Thanks again for your effort guys.

Willem.
Title: Re: Bo Hansén DI layout
Post by: mulletchuck on February 22, 2010, 09:03:00 PM
so, this little DI box is gonna make my lack of chops on stringed instruments sound great, right?    ;D

Can't wait to build this thing, once it's available.    This will be my first DIY hooray!
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on February 22, 2010, 09:52:12 PM
Really Thanks Bo and Soren!!!!
Muchas muchas gracias esa es la manera!!! :D
Best Regards
Title: Re: Bo Hansén DI layout
Post by: llanafreak44 on February 22, 2010, 11:50:39 PM
I'm looking forward to this very much!  ;D



Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on February 23, 2010, 02:27:11 PM
Willem,

Neither Lyrec 532 line input or line output transformer can be use in a DI-box, because wrong impedance and ratio.

Yes, you are right, it was JS Jorgen Schau transformers from the begining, but later on I think Tradania manufacture same transformers for Lyrec tape machines.

--Bo
Title: Re: Bo Hansén DI layout
Post by: mulletchuck on February 23, 2010, 04:48:01 PM
so are we ever closer to seeing a DIY kit for this?  ;D ;D ;D
Title: Re: Bo Hansén DI layout
Post by: justanalogue on February 23, 2010, 07:03:06 PM
Thanks Bo,

have a spare, broken machine and looking to use the transformers of it.
Jakob Erland told me that those Schau trannies are good.

Best regards and thanks again for participating here,

Willem.
Title: Re: Bo Hansén DI layout
Post by: rotation on February 24, 2010, 06:00:51 AM
Hi guys,

i can't add much to your discussion, but i would like to tell you (i think i already said this in this thread:) that this DI is EXCELLENT!
I tested it with OEP A262A3E, Cinemag CMMI-7C and another two. OEP works very very well, it has nice presence. Cinemag sounds a little more "relaxed", clean.
So i don't feel any need to buy "better" transformer than OEP, it works so well.
Btw, we tested OEP/Cinemag version against Radial JDI in mastering studio with really good monitors; Bo's DI was clearly better with any of two transformers, Radial sounded somehow muddy! I might post some soundfiles.
I don't understand why you guys need pcb for this. I built a few p2p and it was so easy.
So thanks to Bo for giving us this schematic and support, i love this DI.

Miha

Title: Re: Bo Hansén DI layout
Post by: flaheu on February 24, 2010, 11:20:59 AM
Hello guys,
I've got this DI that I made years ago with OEP connected 6.45:1, it's sound really good I like it.
I was wondering something, I'll have to use it on stage and I'd like to put 4 of them in a box with a mute for each of them + 1 switchable insert loop per "channel" to plug some stompboxes effects and also I planed to use the amp out to connect to a tuner. All this, is to plug a electro-acoustical guitar, 1 banjo and 1 mandolin + 1 reserve. I would also like to put an additional pad, like -20dB, would this DI support hifh output keyboards ?

-Do you think that this DI can drive long lines ? (small to medium venue max 100m to console)
-Do I have tu put a ground lift at the XLR out ?
-For the mute, can I just disconnect the tx primary from 0v, so my amp out still can drive the tuner ?
-For the insert loop (unbalanced), can I put my DPDT switch between the TX primary "hot" and the 10uF DC blocking cap but after the amp out "node"
-For the -20 dB pad, is the best place just right after the TX secondary (U pad with well matched series resistor) ?

I know it's a lot of question, feel free to comment and/ or give suggestions
Thanks in advance
Title: Re: Bo Hansén DI layout
Post by: rotation on February 24, 2010, 11:47:55 AM
Hello guys,
I've got this DI that I made years ago with OEP connected 6.45:1, it's sound really good I like it.
I was wondering something, I'll have to use it on stage and I'd like to put 4 of them in a box with a mute for each of them + 1 switchable insert loop per "channel" to plug some stompboxes effects and also I planed to use the amp out to connect to a tuner. All this, is to plug a electro-acoustical guitar, 1 banjo and 1 mandolin + 1 reserve. I would also like to put an additional pad, like -20dB, would this DI support hifh output keyboards ?

-Do you think that this DI can drive long lines ? (small to medium venue max 100m to console)
-Do I have tu put a ground lift at the XLR out ?
-For the mute, can I just disconnect the tx primary from 0v, so my amp out still can drive the tuner ?
-For the insert loop (unbalanced), can I put my DPDT switch between the TX primary "hot" and the 10uF DC blocking cap but after the amp out "node"
-For the -20 dB pad, is the best place just right after the TX secondary (U pad with well matched series resistor) ?

I know it's a lot of question, feel free to comment and/ or give suggestions
Thanks in advance


I hope you know it, OEP have to be connected in parallel..
I used it with pretty hot synths and people who heard it said it sounds "present". To my ears this sounded like a little bit of pleasing distortion on mids, pretty useful thing. So i don't think you need pad in front of transformer. Transistor buffer (dual emitter follower) can take very very high signals, so you don't have to pad the signal in front of it, the problem might be transformer. But try it, i like how it "distorts" even with line level signals..
This DI have "automatic ground lift", i hope Bo will explain this better because i don't really understand it either.

I have my own question; as output Z of this DI is pretty low, can it drive line inputs or only mic inputs. I'm asking because signal coming from the output is often hot enough for feeding line ins..

Miha
Title: Re: Bo Hansén DI layout
Post by: ChrisPbass on February 24, 2010, 12:13:21 PM
I've just looked on Bo's website http://web.telia.com/~u31617586/#active DI-box my work horse from 1975

If you go down the page, he shows how to add a DI mod to an API 312 mic amp. If you look at the schematic, there is a -10dB pad switch consisting of a 2.2M resistor in parallel with a 18pF cap and a bypass switch on the DI input.

Perhaps that will work in this context? Answers appreciated  :)

I'm also interested in building a couple of these, so want to make them as versatile as possible.

Chris
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on February 24, 2010, 09:45:38 PM
Flaheu,

Yes, you can add a pad on the DI instrument input. as Chrispbass say, you can use same pad that you can find in my API 325 amp DI modification.
With a double pole toggle switch, 3 position SPDT on-off-on, and a additional 330 kohm resistor, you get a pad switch with 0dB, -10dB, -20dB choice.

My DI-box can handle +19dB (7,5 V) on the input before clipping, and this will be approx. +4dB (1,2 V) on the XLR output over 1kohm load, so a synth or keyboard with out pad is not any problem for the DI-box, but for the microphone input on the mixing console that not have any pad, it can be a headroom problem.

The DI-box can drive very long lines, (same as a good condenser microphone) and if the line are of good quality cable, it can be ok with 100 meters or more.
(but of course, it is also dependent on the console microphone input quality)

The DI-box have a build-in "ground loop suppressor" so in normal case you not need any "ground lift switch".

Disconnect the tx primary from the 10uF output cap, and connect it to 0V/ground. (maybee add a 100K resistor from the 10uF cap. to 0V/ground, this take care of switching pops)

Do not insert the effects loop before the tx primary, because the effect pedals can not drive the transformer, and the transformer can not drive the long cable line.

Place the pad on the instrument input as I say in the beginning here above, it can be ok to do a balanced U-pad un the XLR output, but for the best long line driving, I will go for the input alternative.


Miha,

The "ground loop suppressor" is a old trick, but with only one low ohm resistor to break up the ground connection between electronic ground and chassis ground.
I use a improvment version a "RCD-net", that also take care of high frequency disturbance as RF or light equipment buzz, and ground/earth protection if something strange happend with connected amps and similar.

A line input on modern equipment have in normal appr. 10 k input impedance, so this is not any problem, even older equipmqnt that have 600 ohms impedance are ok.


Chrispbass,

Yes, as I say here above, it is ok to use this pad on my DI-box, and a direct copy, it will be -10dB, because as in the API 325 amp, I use the 1 Mohm ground reference resistor, on the amp input, (or bias resistor in DI-box) as a part of the pad.

--Bo

Title: Re: Bo Hansén DI layout
Post by: flaheu on February 25, 2010, 07:18:40 AM
Thanks your reply.
i will try your suggestions.

Cheers
Title: Re: Bo Hansén DI layout
Post by: ChrisPbass on February 25, 2010, 12:16:09 PM
Thanks for the reply Bo. Is this diagram correct?

Basically use DPDT SWITCH (ON-OFF-ON) wired so:

 toggle up     (SW1 CLOSED, SW2 OPEN) =    0dB
 toggle mid    (SW1 OPEN, SW2 OPEN)    = -10dB
 toggle down  (SW1 OPEN SW2 CLOSED) = -20dB

Have I got this correct?

Thanks for all your input, best wishes

Chris
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on February 25, 2010, 02:03:17 PM
Chris,

You get it absolute right.

--Bo
Title: Re: Bo Hansén DI layout
Post by: ChrisPbass on February 26, 2010, 09:17:18 PM
Thanks Bo  ;D

C
Title: Re: Bo Hansén DI layout
Post by: pacemaker on March 06, 2010, 08:00:13 AM
Hi Bo,
any progress on your metal box design ?
I would be really intersted in buying you a few case
or kits if you have some in order to support
your efforts in this project
But i have to say thanks for the allready done amazing work,
best regards
long life DIY !!!!!!!!!
pacemaker
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on March 06, 2010, 01:20:52 PM
Guy's, have patience, I'm ready very soon.

--Bo
Title: Re: Bo Hansén DI layout
Post by: pacemaker on March 06, 2010, 02:50:50 PM
no problem Bo ,
patience is there,
just wanted to say thanks for this project,
Best regards,
Pacemaker
Title: Re: Bo Hansén DI layout
Post by: mulletchuck on March 09, 2010, 06:27:15 PM
hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry hurry



 ;D ;D ;D

*hint hint*
Title: Re: Bo Hansén DI layout
Post by: mulletchuck on March 19, 2010, 09:57:42 PM
any updates on this?    eagerly awaiting...
Title: Re: Bo Hansén DI layout
Post by: llanafreak44 on March 30, 2010, 05:28:30 PM
Also eagerly waiting a PCB  ;D
Title: Re: Bo Hansén DI layout
Post by: delaymix on March 30, 2010, 09:36:37 PM
Also eagerly waiting a PCB  ;D

+1  ::)
Title: Re: Bo Hansén DI layout
Post by: Neil on April 04, 2010, 12:56:48 PM
Also eagerly waiting a PCB  ;D

+2  :)

Thanks Bo!
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on April 04, 2010, 09:31:05 PM
Sorry for the delay.

Here are the first pictures on the small box version with all connectors on the top.
(the lettering on the front plate are fake)

www.hansenaudio.se/techpage.htm

Note: the inside depth in the box only alow space for Lundahl LL1538 and Haufe ST8456, and have no space for Lundahl LL1538XL or OEP A262A3E.

This small box is manufacture by Deltron and have type number 461-0040, finish in grey powder coated paint, size 115x64x55.
(also in black paint, 461-0040E or naturnal aluminium, 459-0040)
You can buy it from Farnell, RS-Components, ELFA and many others.

Next time I will show pictures on a bigger box with pc-card and connectors placed in the box, not on the top plate.
Maybe I also will add a -10dB input jack, because more space on the bigger box. (this not need any changes on the pc-card)

--Bo
Title: Re: Bo Hansén DI layout
Post by: Ptownkid on April 05, 2010, 09:14:17 AM
Do those links work for anyone?
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on April 05, 2010, 09:40:20 AM
Yes, they works, but I notice that the server is very slow from time to time.

I will take a look on this and see what I can do.

--Bo

Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on April 05, 2010, 09:48:52 AM
Yes, they works, but I notice that the server is very slow from time to time.

I will take a look on this and see what I can do.

--Bo
no Bo,

just release the PCB ;D
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on April 05, 2010, 10:26:48 AM
Silen:arts,

It can take up to 30 seconds before the link will load up, maybe you must try some more times also.

"just release the PCB"

That was good news.
If people will buy, what can I tell them to do ??

Is it the latest version "V8" with the text:  Layout by Luny Tune & Soeren_DK,
next under: Active DI-Box 1975  and  © Bo Hansén 2004.01.20  ??

--Bo
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on April 05, 2010, 10:56:53 AM
It can take up to 30 seconds before the link will load up, maybe you must try some more times also.
we should be patient enough for the gear porn :D
(first pic loaded fast here, 2nd took some time)

"just release the PCB"

That was good news.
If people will buy, what can I tell them to do ??

Is it the latest version "V8" with the text:  layout by Luny Tune & Soeren_DK,
next under: © Bo Hansén 2004.01.20  ??
??? ??? ???
my poor english ::)

but we just need some updates  ;D
Title: Re: Bo Hansén DI layout
Post by: tv on April 05, 2010, 12:01:17 PM
Hey, those photos look nice..
Title: Re: Bo Hansén DI layout
Post by: fdew on April 05, 2010, 01:06:40 PM
I just discovered this forum and this thread.   
Very nice DI box.  I especially like the small size.

How are you planing on doing the printing?
I build a little passive DI and the only way I could come up with that was affordable was to machine the letters in when the other features in the cover were machined.  Your black printing allows for more text and looks sharp.

Again,, Very nice.

Frank
http://lbpinc.com/DI.html
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on April 05, 2010, 02:36:39 PM
Frank,

I don´t think we will supply any ready metal work for this project, only some simple drawing for the hole placement from two boxes I have use for this first sample PC-cards.
So it is up to the DIY people to pick a nice metal box, and do the painting and lettering in a personally way.


Silent:arts,

Sorry, I misunderstand you, I belive you all ready have PC-cards in stock for sale.
The PCB things are Soeren_DK own baby, so contact him for information, updates and layout copyright.

--Bo
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on April 05, 2010, 03:17:28 PM
Silent:arts,
Sorry, I misunderstand you, I belive you all ready have PC-cards in stock for sale.
The PCB things are Soeren_DK own baby, so contact him for information, updates and layout copyright
Bo,
now I feel förnärmad (or is it förolämpad ?)
Ich bin jetzt einfach mal beleidigt ;)

languages ...

I have nothing to sell for this DI, but would like to buy some PCBs to build a couple.
there have never been any plans to sell PCBs for this project on my side.
Title: Re: Bo Hansén DI layout
Post by: pacemaker on April 05, 2010, 04:35:20 PM
i'm in for boards too..
soeren, where are you ?
;-)
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on April 05, 2010, 09:04:34 PM
Silent:arts,

We must clear this up, because it´s still confusion of language between you and me.

You shall absolute not feel offended, (beleidigt) because when you first wrote "just release the PCB" I think you mean that you have make a bunch of PC-cards, and maybe in consultation with Soeren_DK.
In this case I was currious to know if you have use the last and valid version of all PCB versions we have done.

Then when you wrote "but we just need some updates" I say that it was Soeren_DK that handle all information about the PCB layout.

The reason way I think you talk about the PCB's was that me you and Kubi discuss DI-Box 1975 PCB's for your "51X rack system" when we had a long nice e-mail conversation for some month ago, when you was very kind and send me the Haufe ST8456 transformer as a test sample, so I also could add this to the DI-Box PC-board.

Yes, this was the storry, and I hope we have clear up our small misunderstanding.

--Bo
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on April 06, 2010, 02:13:47 AM
Bo, no problem, all cleared up :)
if I do a 51X version you would be for sure the first who knows and proofs the layout.

Soeren_DK, any update from your side? :D
Title: Re: Bo Hansén DI layout
Post by: justanalogue on April 07, 2010, 05:22:53 PM
Beautiful work gentlemen!
I am ready for some boards.

Kind regards,

Willem.
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on April 07, 2010, 05:41:50 PM
hi guys, is possible to self- etch a copper pbc of the "Bo Hansen 1975 DI" with this file  layout http://www.mentol.dk/diy/bohansen/print.pdf (http://www.mentol.dk/diy/bohansen/print.pdf) Is this 100% functional???

I saw in your  picture (BO) "DI front and card"   that you used  carbon 5% resistors in the DI?? exept the 6K8 1% . Is this better for the classic sound of the 1975 DI???

best regards
Juanjo..
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on April 07, 2010, 07:44:18 PM
Joanjo,

This PCB print was the version I use as test sample, and it´s ok beside some small error as components that was placed to tight together.

Soeren_DK work just now on the latest and final PCB version.

About the components,
This design is not so choosy regarding resistors or other components, (besides the two 6.8k phantom feed resistors) it is only a simple dual emitter follower, "no gain no pain" so use what you have on the shelf.

--Bo
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on April 07, 2010, 07:53:54 PM
Hi Bo!!!! , Ok, I will wait for the final PCB and thanks for the 1975 DI!!!

best regards!
Juanjo
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on April 11, 2010, 03:16:34 AM
Sorry guys.
I didn't receive any notifications from this thread so I didn't visit it... Sorry sorry sorry... :) :) :)
Bo have corrected the last part of the pcb so I will finish it in the next week and then contact Gustav and make a run.

@Bo
I write to you tonight... ;-)

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: llanafreak44 on April 11, 2010, 03:59:23 AM
Excellent! Can't wait  ;D
Title: Re: Bo Hansén DI layout
Post by: sonolink on April 11, 2010, 09:34:51 PM
Can I use a Lorlin 2P switch such as this one for the PAD mentioned by Chrispbass?
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=ck1030

Thanks
Sono
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on April 15, 2010, 02:28:18 PM
Can I use a Lorlin 2P switch such as this one for the PAD mentioned by Chrispbass?
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=ck1030

Thanks
Sono
Yes.. It will work..
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on April 15, 2010, 02:29:16 PM
PRINT DESIGN. . . . . . . work in progress

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: frederikkofoed on April 15, 2010, 04:33:55 PM
PRINT DESIGN. . . . . . . work in progress

Cheers
Soren

Hi Søren

When can we expect to have the pcbs ready.. :)

- Frederik
Title: Re: Bo Hansén DI layout
Post by: justanalogue on April 15, 2010, 05:06:58 PM
PRINT DESIGN. . . . . . . work in progress

Cheers
Soren

Again thanks so much for all the work!

Willem.
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on April 16, 2010, 04:04:07 AM
The files are delivered to Gustav, waiting for an estimated date for the pcb to show up in his thread.

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on April 16, 2010, 02:53:42 PM
Hi Guys!

Soren and Bo,

Please, is possible to post here the PCB Silk (final version) and the Self-Etch Files of the final PCB copper layout? ;D

Again, thanks a lot  for this thread.

best regards,
Mucha Suerte y
chao

Juanjo
Title: Re: Bo Hansén DI layout
Post by: grantlack on April 16, 2010, 08:01:08 PM
such good news!  i think i may have just squealed like a little girl, looks like i'll be modding some stage boxes soon.  prost to all for the time and effort!

The files are delivered to Gustav, waiting for an estimated date for the pcb to show up in his thread.

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: nhaudio on April 17, 2010, 08:21:02 AM
I Soren,

could you go through the updates to this latest design? I had home-etched the design you've posted here. Is there a lot of difference between them?

cheers

Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on April 17, 2010, 03:06:12 PM
Hi nhaudio.
Great to hear you have completed the etching with luck.  ;) ;)
The only difference from the latest design is the placement of the components. The schematic is unchanged.

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on April 20, 2010, 09:08:39 AM
Update
In a couple of weeks the boards will be ready if there is no problems with the Gerber files.

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: oragall on May 04, 2010, 05:38:10 PM
i have a edcor pc 1/4W  series (600 to 15K) , the relation of this trafo is 1:5 , work well,  ot not with this trafo.????
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on May 04, 2010, 09:29:17 PM
oragall,

Not the best impedance match, but try it, you newer know, maybe it will work fairly good.

--Bo
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on May 06, 2010, 03:10:56 PM
NEWS FLASH
The boards is now available in gustavs shop :) :) :) :) :) :) :)
http://www.groupdiy.com/index.php?topic=10776.0

Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on May 06, 2010, 04:05:15 PM
I think I need to place an order tomorrow.
to Gustav and Haufe  8)
Title: Re: Bo Hansén DI layout
Post by: oragall on May 06, 2010, 08:32:59 PM
tnx bo, maybe y test whit the trafo. Need only time, but now i finish other project.
Title: Re: Bo Hansén DI layout
Post by: sonolink on May 07, 2010, 09:25:48 AM
I'd like to have a go at self-etching this board. Any chance the final PCB version could be posted, please?
Cheers
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on May 07, 2010, 12:53:43 PM
Hi Guys!!

I would like self-etch my own PCBs too.  ;D

If it is possible, please, post the Final copper side layout and the silk side. ;)

Thanks for this thread and best regards
mucha suerte y chao

Juanjo..
Title: Re: Bo Hansén DI layout
Post by: briomusic on May 10, 2010, 05:12:15 AM
Between Christmas/New Year I will try to do a transformer test/evaluation and compare Lundahl, Haufe and OEP in the DI-Box electronics.

But Just now I wait for a sample of OEP A262A3E from UK, so I will start when I receive that.

--Bo

Hi Bo,
did you ever get round to comparing the sound of these transformers in your circuit?
Would be very interested in hearing (or hearing about) results as these transformers are quite different in price etc.
Thanks,
briomusic

Title: Re: Bo Hansén DI layout
Post by: pacemaker on May 10, 2010, 09:02:15 AM
yes i agree,
seems that a lot of people like the OEP in this build
Cinemag too,
But your impression with Lunhdal and Jensen would be interesting
Also with Edcor, Altran ....
Title: Re: Bo Hansén DI layout
Post by: sonolink on May 10, 2010, 10:15:42 AM
I'd like to have a go at self-etching this board. Any chance the final PCB version could be posted, please?
Cheers


I guess that's a no no then, right?
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on May 11, 2010, 04:48:21 AM
I'd like to have a go at self-etching this board. Any chance the final PCB version could be posted, please?
Cheers


I guess that's a no no then, right?
Sorry guys. I didn't got so much time but I have done it now. Its in the first post..

Best regards
Soren
Title: Re: Bo Hansén DI layout
Post by: sonolink on May 11, 2010, 05:01:00 AM
Thanks Soren. Ur my hero  ;D
Title: Re: Bo Hansén DI layout
Post by: juanjovincenzo on May 11, 2010, 09:02:15 AM
Hi!!
Thanks again Soren!!!!
"ESA ES!!!!"
BEST REGARDS
Y SUERTE

Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on May 11, 2010, 03:36:44 PM
briomusic,

Yes, I have done some tests and compare Lundahl LL1538, Haufe ST8456 and Walters OEP A262A3E, in my DI-box circuit.

Lundahl and Haufe have near same behavior from 100 Hz and up, but Haufe are a bit better in low end small signal distortion, and Lundahl have lower distortion in low end near saturation point.

Both have a very good square wave response, and have 14 dB loss with 1 kohm total load.

OEP have approx. 10 times higher distortion from 100 Hz and down, and have also higher distortion in the high end, but have ok square wave response, slightly rounded, with out ringing or overshoot.
Because the 6,45:1 ratio, it have 16 dB loss.

All three sounds nice in my DI-box, but Lundahl LL1538 are still the best with a steady and clean low bottom and a fast and clear high end.

--Bo

Title: Re: Bo Hansén DI layout
Post by: briomusic on May 11, 2010, 03:48:27 PM
bo

I am sure I am speaking for many forum members in thanking you for this run down!
can't wait to build your DI now!

briomusic
Title: Re: Bo Hansén DI layout
Post by: neodyms on May 12, 2010, 01:33:28 PM
Hi Bo
your impression with Haufe, OEP and Lunhdal
are very interesting,
did you tested the DI with Jensen, Cinemag or Edcor
as pacemaker asked ?
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on May 12, 2010, 02:43:18 PM
neoyms,

Of course mike transformers as Jensen JT-13K7A and Cinemag CMMI-5C are great transformers, (maybe a bit low impedance on secundary) I have not test them in this DI-circuit, but I´m sure they will work very nice.

Cinemag have some other types as CMO-5/200, CM-2461NiCo, CM-24110 and CMMI-7C, and can maybe also fit very well in this circuit.

About Edcor,
Yes, I have test MX-5, 1:5 mike transformer.
Sorry to say, not so good, maybe it can be usable in other applications, but not for a DI-box like mine.

There are other usable brands and types that you can try:
Sowter 3195, 3678, 4935, 8230
Steven & Billington 829
Amplimo TM2P

And of course the old famous Neve mike transformer
10468 / VT22670 / T1454, (configurated 4,8K to 300 ohm)
to day made by Carnhill, type VTB9045, or Sowter 9145.

--Bo
Title: Re: Bo Hansén DI layout
Post by: pacemaker on May 13, 2010, 07:30:41 AM
What about the Cinemag  CM-DBX
does anybody has tested it in this circuit ?
i suppose we can use a lot of transformer brands
in order to "color" the sound
or neutrality transparency
Seems like Rotation says the OEP is a bit raw and has a nice color
I suppose Lundahl are kind of "HI-FI" and appreciated by Bo,
Francois
Title: Re: Bo Hansén DI layout
Post by: spacecho on May 14, 2010, 02:40:35 AM
hey Guys,

i have a lundahl ll1530 - could this work ok in this circuit?
it is a 1+1: 3,5+3,5 mic transformer which can be wired 1:7

i'm guessing that apart from a steeper level drop it should perform ok?


Title: Re: Bo Hansén DI layout
Post by: llanafreak44 on May 14, 2010, 03:05:51 AM
So which Tranny are you Americans using? All the recommended ones are European companies.
Title: Re: Bo Hansén DI layout
Post by: Neil on May 14, 2010, 04:57:10 PM
So which Tranny are you Americans using? All the recommended ones are European companies.

Good question! I'm planning on a Lundahl LL1538 on one, but I'm undecided on the other.

Does anyone have a good suggestion to complement the LL1538? Something a little different sound-wise.
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on May 14, 2010, 09:20:31 PM
I have now recieve a couple of the first batch of the real final pc-cards, and i will give a big compliment to Soren, Torben and Gustav for a great work on this pc-cards, they are very nice and of first class.

About transformers.

You can use all brands and types, if they are microphon transformers, and if they have a primary on 150 or 200 ohms and have a ratio around 1:5 to 1:10, and of course you must connect them backwards in my DI-circuit.

Higher ratio, (10:1) gives more loss from instrument input to balanced output.
The optimal loss for a active DI-box are around -15dB, to match a console microphone input best, so for a 200 ohms "primary" a ratio around 5:1 will fit best, but up to 7:1 can be ok.
But be sure that you configurate primary and secondary windings right, because some transformer can have a lot of impedance/ratio combinations.

There ar a lot of brands of US made transformers as Sescom, Chrimson, Pico, Microtran, Hammond, and many others.

With advantage can older types of "matching" transformers be use in my DI-circuit, like brands as UTC, Freed, Stancor, Altec/Peerless, Triad, Thordarson, Kenyon, Dukane, and many others US made brands.

But watch up for "microphone to grides" types, they have to high ratio for this application.

--Bo
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on May 19, 2010, 07:13:25 AM
Hi Bo.

Can I use other transistors instead of the BC550C and the BC560C?

I have a lot of:

BC328
BC338
BC547B
BC557B


Cheers
Soren
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on May 19, 2010, 03:50:32 PM
Soren,

You can use near all small signal general purpose transistors, that have Vceo 30 volt as minimum, hFE from 200 and up, and fT from 100 mHz and up.

I use BC550-C and BC560-C because this was very easy to get around the world for a couple of years ago, and with right manufactures they was very good  genaral purpose low noise audio transistors.

The pc-card are done for transistors that have TO-92 with pin configuration like a old TO-18 in metal can as BC109.
Here are some other transistor types that direct fit on the pc-card. (not need to twist any legs)

BC550=NPN
BC560=PNP

NPN: BC550, BC549,  BC546, BC547, BC548, all B or C
PNP: BC560, BC559,  BC556, BC557, BC558, all B or C

Here are some older TO-18 transistors in metal can, that also fit direct in the holes.
NPN: BC109, BC108 B or C
PNP: BC179, BC178, BC177 B or C

Then you have hundreds other NPN and PNP transistor, but maybee you must twist the legs to fit in right holes on the pc-card, and you must be 100% sure that you know the transistor pin-out.

Here is some well known NPN and PNP pair that you often can see work together in various audio gear around the years.
As I say before, watch out with pin-out.

NPN: 2SC2240,  PNP: 2SA970 GR or BL (the best pair of all transistors)
NPN: 2SC1815,  PNP: 2SA1015 GR or BL

NPN: BC184,  PNP: BC214 B or C
NPN: BC182,  PNP: BC216 B or C
NPN: BC414,  PNP: BC416 B or C

NPN: 2N4401,  PNP: 2N4403
NPN: 2N4124,  PNP: 2N4126
NPN: 2N5210 or 2N5088,  PNP: 2N5087
NPN: 2N3707,  PNP: 2N3702
NPN: MPSA18, PNP: ------
Of course you can mix all NPN and PNP in a combination.

--Bo
Title: Re: Bo Hansén DI layout
Post by: Neil on May 24, 2010, 12:25:21 PM
I started building mine, but have two questions-

Bo's schematic on his website calls for a .047 uF cap between XLR pin 1 and Monitor Amp Out (-) but on the circuit board it's labelled .1 uf.

Also, on the schematic right beside the .047 uF capacitor there's a 47 ohm resistor, but on the circuit board it's 100 ohm (right below the two 1N4004 diodes).

Which one is right, or can you use either one?
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on May 24, 2010, 07:51:10 PM
Neil,

I have done some value correction the last years, but I have not change the schematic yet.
(new tech page with better info will be displayed soon)

Here are all change I have done:

two 470K to 100K
1uF to 10uF
47 ohm to 100 ohm
0,047uF to 0.1uF

So the component value on the pc-bord are absolute right.

--Bo
Title: Re: Bo Hansén DI layout
Post by: Neil on May 24, 2010, 07:58:09 PM
Ok, thanks Bo! I read your notes on the web page but since those components weren't mentioned I thought I'd ask to be safe.
Title: Re: Bo Hansén DI layout
Post by: joellegros on May 25, 2010, 10:19:46 AM
Anyone know if there is a US distributor for the Haufe ST8456?  Went to their website, but it's all in german (someone mentioned I think).  I will probably build one with Lundahl 1538 first, but would eventually like to try out the Haufe. 

I came up with a layout with a friend last night, but I think I might try this one since it's been tested.  Also, I think I'm going to use a Hammond 1590CGY to enclose it. 

Thanks Bo and everyone who helped make this project possible!
Title: Re: Bo Hansén DI layout
Post by: ericjazz on May 31, 2010, 01:57:06 PM
Hello,
Does anyone know dimensions (height) for the ST8456? Need to choose the right case (I'm thinking of this: http://www.thomann.de/fr/millenium_die_dibox_passiv.htm, but height can be insufficient...).
Btw, if french guys are ok for a Haufe group buy, then pm me.
Thanks to Bo and Soren for this great project.
Best regards.
Eric
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on May 31, 2010, 03:04:29 PM
Does anyone know dimensions (height) for the ST8456?
yes: 16mm
Title: Re: Bo Hansén DI layout
Post by: briomusic on May 31, 2010, 03:49:22 PM
Does anyone know dimensions (height) for the ST8456? Need to choose the right case (I'm thinking of this: http://www.thomann.de/fr/millenium_die_dibox_passiv.htm, but height can be insufficient...).
wow: case, connectors and two switches for €10 - pretty cool  :D
Title: Re: Bo Hansén DI layout
Post by: diyfanatic on June 01, 2010, 05:27:47 AM
Another one @ thomann 58€  With Haufe trafo :o

Millenium DI-Pro - professional passive DI box - Haufe transformer, XLR/jack in, XLR/jack link, XLR/jack out (Haufe transformer), ground lift switch.

 http://www.thomann.de/fr/millenium_dipro.htm
Title: Re: Bo Hansén DI layout
Post by: ericjazz on June 01, 2010, 02:42:21 PM
Thanks for the answers. Millenium DI-Pro is interesting.... I wonder what type is this Haufe transformer.
For your information, I received pricing for 4*ST8456 : 217,55EUR incl shipping to France...
Best regards.
Eric
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on June 01, 2010, 03:08:52 PM
FYI

I will receive some Haufe ST8456 in the next two weeks.
since I ordered a larger batch I can let them go at
EUR 28,30 each + shipping + 19% VAT (if applicable)
Title: Re: Bo Hansén DI layout
Post by: mrcase on June 04, 2010, 11:01:21 AM
thats a good deal on the haufe transformers.
do you have them in stock already?

Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on June 04, 2010, 12:02:18 PM
not in stock, but I'm awaiting them next week.
Title: Re: Bo Hansén DI layout
Post by: benlindell on June 04, 2010, 01:18:45 PM
I'd definitely like to get a pair of those transformers when you get them in.
Title: Re: Bo Hansén DI layout
Post by: mrcase on June 04, 2010, 01:29:11 PM
count me in for 2 please!
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on June 04, 2010, 01:35:54 PM
guys, I will serve you, but please let us leave this thread to the great DI ...
will post somewhere else once I have the transformers in hand.
Title: Re: Bo Hansén DI layout
Post by: neodyms on June 09, 2010, 09:31:08 AM
hi all !

For every body finished this Project, what's your impressions about the sound, the fidelity ?

Title: Re: Bo Hansén DI layout
Post by: Jed on June 09, 2010, 03:45:42 PM
I just finished one last night with the OEP transformer.

I haven't spent a lot of time with it yet - just a quick test with electric  bass and electric guitar against a GT passive DI.  

This DI has a much higher output and also seemed to have more high frequency content. Overall it sounds **great**.

I can't wait to use it more.

Thanks very much to Bo for providing this design to the world, and to Soeren and any others who helped out for making it such an easy project!

Jed
Title: Re: Bo Hansén DI layout
Post by: sverige_cruz on June 11, 2010, 02:14:38 AM
(http://i1034.photobucket.com/albums/a426/sverige_cruz/DIY%20-%20Pro%20Audio/th_HANSEN.jpg) (http://s1034.photobucket.com/albums/a426/sverige_cruz/DIY%20-%20Pro%20Audio/?action=view&current=HANSEN.jpg)

Thanks to Bo and Soren for putting the work into this. First impression is that it sounds great. Wish I would have built this a long time ago.

Cheers,
Jesus


PS - Tecate tastes a hell of a lot better with lemon... (cheap beer so I can buy more components)  8)
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on June 11, 2010, 10:56:05 AM
thats a good deal on the haufe transformers.
do you have them in stock already?
now in stock:
http://www.groupdiy.com/index.php?topic=39570.0
Title: Re: Bo Hansén DI layout
Post by: wowi on June 13, 2010, 12:19:22 PM
Thanks for the answers. Millenium DI-Pro is interesting.... I wonder what type is this Haufe transformer.
For your information, I received pricing for 4*ST8456 : 217,55EUR incl shipping to France...
Best regards.
Eric

It's a Haufe ST8123

Wolfgang
Title: Re: Bo Hansén DI layout
Post by: RedNoise on June 13, 2010, 02:34:54 PM
Hi , do someone know the dimensions of the pcbs please ?
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on June 13, 2010, 02:53:39 PM
Hi , do someone know the dimensions of the pcbs please ?

50 x 80 mm  ;)

Cheers
Søren
Title: Re: Bo Hansén DI layout
Post by: RedNoise on June 13, 2010, 03:34:03 PM
thousand thanks!! ;D
Title: Re: Bo Hansén DI layout
Post by: pacemaker on June 14, 2010, 06:02:55 AM
Hi Soeren and Bo,
it might me a dumb question
but what is the purpose of the "chassis" pin hole,
i thought the only connection to chassis was through the XLR pin 1,
regards,
Francois
Title: Re: Bo Hansén DI layout
Post by: zebra50 on June 15, 2010, 03:33:11 AM
Take another look at the bottom right of the schematic.

You can see that pin 1 is lifted above ground with a cap, 2 diodes and a resistor.
Title: Re: Bo Hansén DI layout
Post by: pacemaker on June 16, 2010, 05:21:54 AM
on the schematics it is,
but not on the boards,
there's a trace between pin 1 hole and "chassis" hole,
or am i missing something ?
regards,
Francois
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on June 16, 2010, 12:45:05 PM
Francois,

Everything is ok,

The metal box "chassis" shall be connected to XLR pin 1, so it is the electronic ground "0 volt" on the pc-card, that is isolated from XLR pin 1 and metal box with the "ground loop circuit" build with two dodes, one 100 ohm resistor and 0,1uF capacitor.

Ok, you can do the pin 1 connection to metal chassis direct on the XLR connector, but it more safe to use the connection from pc-card to a solder tag/lug with a separate screw direct to metal chassis.

NOTE, both tele jacks must be isolated from the metal chassis, use "Cliff Plastic" brand, mono-BB version, they are the best for this application.

--Bo
Title: Re: Bo Hansén DI layout
Post by: VanGenz on June 17, 2010, 05:35:38 PM
What is the input impedance of this DI?
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on June 17, 2010, 05:40:34 PM
What is the input impedance of this DI?
1M ohm...  ;)

Cheers
Søren
Title: Re: Bo Hansén DI layout
Post by: benlindell on June 21, 2010, 11:39:09 AM
I ordered some boards and transformers this weekend. I just made up a BOM for anyone that's interested.

http://benlindell.com/diy/Bo-Hansen-DI-BOM.pdf (http://benlindell.com/diy/Bo-Hansen-DI-BOM.pdf)

Excited to hear this thing.
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on June 21, 2010, 02:06:58 PM
I ordered some boards and transformers this weekend. I just made up a BOM for anyone that's interested.

http://benlindell.com/diy/Bo-Hansen-DI-BOM.pdf (http://benlindell.com/diy/Bo-Hansen-DI-BOM.pdf)

Excited to hear this thing.
Thanks ;) ;)
I have updated the first post..

Cheers
Søren
Title: Re: Bo Hansén DI layout
Post by: diyfanatic on June 22, 2010, 07:21:37 AM
I've made a BOM too (waiting to for my tx and board)

for European @ banzaieffect:

http://docs.google.com/leaf?id=0B2Ajbn3wU-UiN2Y1OWJkN2MtYzVhZi00Nzc3LWE1OWEtZjcwMGExZGRkZWUz&hl=en

everything is linked so it should be easy but use it at your own risk... ::)
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on June 22, 2010, 08:49:30 AM
I've made a BOM too (waiting to for my tx and board)

for European @ banzaieffect:

http://docs.google.com/leaf?id=0B2Ajbn3wU-UiN2Y1OWJkN2MtYzVhZi00Nzc3LWE1OWEtZjcwMGExZGRkZWUz&hl=en

everything is linked so it should be easy but use it at your own risk... ::)
Thanks.  ;)Updated the first post ;) ;)

Cheers
Søren
Title: Re: Bo Hansén DI layout
Post by: justanalogue on June 22, 2010, 12:12:17 PM
Received my boards today.
Nice work, thanks to all involved in this.

Kind regards,

Willem.
Title: Re: Bo Hansén DI layout
Post by: AMaziad on June 22, 2010, 03:44:01 PM
I have a question for the people using the OEP.  Are you using it with the Mu-Metal Can or without?  I'm about to order parts and was wondering if the can is necessary. 

Thanks.
Title: Re: Bo Hansén DI layout
Post by: Jed on June 22, 2010, 03:50:32 PM
I used it with the can. I did not try it without...
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on June 22, 2010, 03:53:28 PM
Amaziad,

When you build it in a metall box, you not need the mumetal case for the OEP transformer.

--Bo
Title: Re: Bo Hansén DI layout
Post by: neodyms on June 25, 2010, 09:12:47 AM
Hi bo,

I just finished Two of your Active Di's with Lundahl LL1538 mount and i'm starting some tests.

for the input impedance no problem with a big input load it work very good very clear(tested with an active Bass).

but the problem is more around the output level witch is quite low .

to compare, i have a 6dB less than a basic BSS AR133 DI Box.

is it possible to boost this output ?
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on June 26, 2010, 07:11:44 AM
Neodyms,
(and other that wonder about output level and input impedance)

About your low output problem.

Here are a copy from one of my early postings. (19 December 2009)

If everything is ok, and you have connected the transformer fore 5:1 configuration you shall have around 15 dB loss from instrument input to XLR balanced out. (no loss, 1:1 from instrument input to monitor amp out)

Because you use a microphone transformer backwards you get "loss" negative gain, and a 1:5 ratio transformer have approx. 15 dB step-up gain, or loss used backwards.

You want loss in a DI-box, because the level from a guitar or bass, (after a 1:1 impedance converting) are to high to match a console microphone input.

I will guess that mostly of active DI-boxes on the market have approx. 5-15 dB loss, and passive have approx. 20-30 dB loss.

If you after all need more gain, use the 2,5:1 configuaration instead for the 5:1 configuraton on the Lundahl LL-1538 transformer and you get only 10 dB loss instead for 15 dB, and have 5 dB more gain out from the DI-box.
(but the best transformer match in this circuit are the 5:1 configuration)


I will add to the posting above.
There are some active transformator-less DI-boxes on the market, some of them have high output, because the electronic have unity gain 1:1 from in to output, (some have +6dB gain) and they have only a pad with a small amount of dB.
This can sometime be to much output level for a microphone input on a preamp or mixing console.

About the input impedance.

I megohm is not a low impedance for passive instruments as electric guitars and bass guitars.
I megohm are the most usually impedance for instrument amplifiers around the years, and I think the guitar manufactures have this in mind when they design pickups and guitar electronics.

Many JFET DI-boxes on the market have 10 megohm input impedance and this can be very nice for some instruments, because it will "suck out" everything from a passive guitar, and it also change the sound character and volume/tone knobs behavior.

10 megohms impedance can also be nice when you use acoustic guitars with Piezo pickups direct to a DI-box.

My old DI-box design from 1975, have not a JFET transistor as front end transistor, it is a bipolar silicon type, and it can not handle higher impedance then some megohms.
I will not change this design to JFET, because it is "the part of the sound" and it is also easy to find bipolar transitors and it work without any adjustments.

If you use an active bass, you have internal electronics with a output driven from a op-amp or transistor amp, so in this case, 1 mohm is very high and nice impedance for instruments with internal active electronics.

--Bo
Title: Re: Bo Hansén DI layout
Post by: mac on June 27, 2010, 12:31:23 AM
apologies if I missed this in the thread somewhere, but what is the significance of the 1% for the 6k8 resistors?


Mac
Title: Re: Bo Hansén DI layout
Post by: neodyms on June 28, 2010, 05:14:51 PM
hi bo thank you for your reply.

i didn't yet test that mod but i have an other question ?

have can you do to make a variable input impedance on this schematic? and witch values ? (in the wish to get polyvalent DI)

cordially
Title: Re: Bo Hansén DI layout
Post by: AMaziad on June 28, 2010, 05:30:02 PM
Amaziad,

When you build it in a metall box, you not need the mumetal case for the OEP transformer.

--Bo

Thanks for the quick response Bo - if only my reply was as quick.  Also, thanks for this great design, I can't wait to get started on the build.

- Ali
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on June 28, 2010, 07:30:21 PM
Mac,

This two 6,8 kohm resistors are the receive phantom feed resistors in the DI-box end, so to not distrub the balanced line, (common mode reaction) the resistors must be in 1% tolerans.

--Bo
Title: Re: Bo Hansén DI layout
Post by: mac on June 28, 2010, 08:18:22 PM
Hey Bo,
First up thanks for this project - awesome. I made one last night (self etch) and used a XSM Edcor 600/10k for testing. I have some other transformers on the way to trial (OEP, a cheaper Chinese one).

Yeah, now you say it, the 1% make sense for the phantom.

Last night I tried a few transistor pairs pulled from old gear I have lying around and there wasnt a huge difference in sound.

20 year old BC548 and BC558
brand new BC550 and BC558
20 year old BC109 and BC178

It is anticipated that different transistor pairs would make a big impact on the nature of the sound? Obviously the different transformers will make a huge difference.

Mac
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on June 29, 2010, 07:06:19 AM
Neodymsn

There are no need to change input impedance on this DI-box because it have a good compromise impedance of 1 megohm usable for the mostley of all passive electric guitars and bases.

There are som bass guitars that can be coloured in a nice way when you use a passive transformer DI-box that have lower impedanse as 100 kohms or less.
(UTC LS10X or similar old great "low-Z mike or line to grids" types)

So if you want lower impedance on my DI-box, you can try to connect for a example a 100 kohm resistor direct on the guitar cable plugg or on the DI-box input jack between tip and ground.
But I think a input on a DI-box transformer can have a other sound behavior on passive guitars compare with a resistor.

Mac

When you try "new" transistors, be sure that you use types from good manufactures as Philips/PH, Motorola/Onsemi, SGS/Ates, Fairchild, National, because this other "no name" MBR types can bee very awful in small signal parameters, and this can infect the sound quality even in this simple "dual emiterfollower circuit.

--Bo
Title: Re: Bo Hansén DI layout
Post by: ChrisPbass on June 29, 2010, 07:40:16 AM
Hey Bo,
First up thanks for this project - awesome. I made one last night (self etch) and used a XSM Edcor 600/10k for testing. I have some other transformers on the way to trial (OEP, a cheaper Chinese one).

Yeah, now you say it, the 1% make sense for the phantom.

Last night I tried a few transistor pairs pulled from old gear I have lying around and there wasnt a huge difference in sound.

20 year old BC548 and BC558
brand new BC550 and BC558
20 year old BC109 and BC178

It is anticipated that different transistor pairs would make a big impact on the nature of the sound? Obviously the different transformers will make a huge difference.

Mac

Hi Mac, can you let us know how you found the edcor in your testing please?
Cheers
Chris
Title: Re: Bo Hansén DI layout
Post by: neodyms on June 29, 2010, 12:56:38 PM
Hi bo

about 1Mohm i'm sure it's a good input impedance to. (for basses to piezzo)

But i was thinking about a variable imput impendance from 1MOhm to 10 MOhm.

Do you think it's a interesting idea ?
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on June 29, 2010, 02:49:03 PM
Neodyms,

Yes, 1 megohm is very ok for guitar and bases, but not for piezo pickups that need about 10 megohm.

Have you read what I wrote to you here ??
http://www.groupdiy.com/index.php?topic=36569.msg491675#msg491675

You can not go up to 10 megohm on this DI-box design that have a bipolar transistor as front end.

If you want 10 megohm you shall build one with JFET-transistor as "countryhick" that you also can find on this forum as a DIY project.

Omong some other things, the 1 megohm and a bipolar front end transistor are "the part of the sound" for my "DI-box 1975"

Instead you shall build three different DI-boxes, one as mine with 1 megohm input, one with lower impedance as a passive transformer box, and one with higher impedance with JFET-transistor (or JFET op-amp) as front end to get 10 megohm.
This is nice because they will sound in three different way, and it is very usable to try on different instruments.

--Bo
Title: Re: Bo Hansén DI layout
Post by: mac on June 30, 2010, 12:05:53 AM
Quote
Hi Mac, can you let us know how you found the edcor in your testing please?
Cheers Chris

Hey Chris, I hate grappling for adjectives to describe sound (very subjective) - but to my ears I was surprised that the Edcor actually sounded a little bigger and clearer than the little OEP.

at the risk of sounding quite rediculous - the OEP sounds more APIish .... (i will now go and inflict punishment upon myself)...

Of course the edcor is physically much bigger and would need mounting off board so you would need a much larger enclosure (particularly if you are building a stereo unit for keyboards like I am)....

Mac
Title: Re: Bo Hansén DI layout
Post by: ChrisPbass on June 30, 2010, 08:19:32 AM
Quote
Hi Mac, can you let us know how you found the edcor in your testing please?
Cheers Chris

Hey Chris, I hate grappling for adjectives to describe sound (very subjective) - but to my ears I was surprised that the Edcor actually sounded a little bigger and clearer than the little OEP.

at the risk of sounding quite rediculous - the OEP sounds more APIish .... (i will now go and inflict punishment upon myself)...

Of course the edcor is physically much bigger and would need mounting off board so you would need a much larger enclosure (particularly if you are building a stereo unit for keyboards like I am)....

Mac


Thanks for the reply Mac, now go and shut your computer down and promise not to return to Prodigy Pro for at least 24 hours as your punishment   ;D
Interesting regarding the edcor, I'll get some extra ones to try when I place my order with them for DAOC trannys. They're cheap enough I suppose. Flavours, flavours, flavours...
Cheers
Chris
Title: Re: Bo Hansén DI layout
Post by: mac on June 30, 2010, 09:19:56 PM
<<<<RED CARD >>>>> 24HR break inserted>>>>

Yes, actually it makes me wonder about switchable transformers or maybe some simple filters. A friend of mine wants me to try and solve a problem for hi buy building one with different flavours in the box. He has a couple of different acoustic guitars that all present slightly different tone challenges and at the moment he runs a DI, a BBE sonic maximiser and an EQ to solve these issues on stage (banjo too bright, Maton too muddy, etc etc).

One box - DI with different flavour transformers and some simple two channel parametric tone control in one box might solve all these problems for him.

Mac
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on July 08, 2010, 05:10:17 PM
Note,

Under this summer I done changes on my web site, so some pages is not in function just now. (as the old link for DI-box schematic)

My DIY/Tech Pages have now a new address, and have access from my main page: www.hansenaudio.se
the direct link is: www.hansenaudio.se/techpage.htm

Sören,
please, can you change the schematic link in your first posting.

--Bo
Title: Re: Bo Hansén DI layout
Post by: Soeren_DK on July 08, 2010, 05:22:50 PM
Note,

Under this summer I done changes on my web site, so some pages is not in function just now. (as the old link for DI-box schematic)

My DIY/Tech Pages have now a new address, and have access from my main page: www.hansenaudio.se
the direct link is: www.hansenaudio.se/techpage

Soeren, please, can you change the schematic link in your first posting.

--Bo
Hi Bo.
I have corrected the first page links.
I like your new structure of your tech site. Easy reading and understanding ;) ;) ;D

God Sommer :o :D

Cheers
Søren
Title: Re: Bo Hansén DI layout
Post by: mac on July 12, 2010, 12:52:18 AM
Hi All,
finally got around to dropping my first one in a box last night (only using recycled junk I have around here). Note the transistor sockets...

I listened to about thirty pairs last night until I swear I was hearing things!!
Next one will be in a proper box with enough space for edcors!


(http://i858.photobucket.com/albums/ab141/macglider/bo%20hansen%20di/di007.jpg)

(http://i858.photobucket.com/albums/ab141/macglider/bo%20hansen%20di/di006.jpg)

(http://i858.photobucket.com/albums/ab141/macglider/bo%20hansen%20di/di003.jpg)

(http://i858.photobucket.com/albums/ab141/macglider/bo%20hansen%20di/di004.jpg)

(http://i858.photobucket.com/albums/ab141/macglider/bo%20hansen%20di/di005.jpg)
Title: Re: Bo Hansén DI layout
Post by: AMaziad on July 12, 2010, 02:49:47 AM

(http://i858.photobucket.com/albums/ab141/macglider/bo%20hansen%20di/di005.jpg)


I really like the case.  If you don't mind me ask, what type is it?
Title: Re: Bo Hansén DI layout
Post by: mac on July 12, 2010, 03:19:32 AM
Hey Amaziad,

It is just a recycled enclosure (an old blown 12v -240v inverter). I had to cover the existing holes with some creative thinking (hence the alloy badge!!).


Mac
Title: Re: Bo Hansén DI layout
Post by: nhaudio on July 17, 2010, 09:25:07 PM
Got them done today..home etched, transformers are BeyerDynamic 5:1 that match the impedance specs and transistors are bc550 C's and 560 B's.
First impression is that the sound is really punchy. Thanks to all and to Bo and Soeren in particular for this really cool project.

(http://i975.photobucket.com/albums/ae238/nhaudio/P1000745.jpg)

(http://i975.photobucket.com/albums/ae238/nhaudio/P1000740.jpg)

(http://i975.photobucket.com/albums/ae238/nhaudio/P1000739.jpg)
Title: Re: Bo Hansén DI layout
Post by: Nele on July 17, 2010, 09:34:42 PM
nice!  :)
how is the bass-response with the beyers?
 
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on July 18, 2010, 05:47:25 AM
Nice to see all building samples like version from mac and nhaudio.

nhaudi,
use isolated plastic jacks, (or metall jacks with isolated washer) to get the ground system to prevent ground loops.

You must also isolate the transformer case from the metal box, because transformer shall only be connected to the pc-board electronic ground.

Use red LED, because this colour have lowest voltage drop.

--Bo
Title: Re: Bo Hansén DI layout
Post by: nhaudio on July 23, 2010, 08:03:49 AM
@nele - bass response... I don't have any other transfo/di to compare it to but to my ears it sounds good.


@bo - Thanks for the tip.
Title: Re: Bo Hansén DI layout
Post by: justanalogue on August 02, 2010, 02:27:54 PM
Finished the 1st one...not tested yet.

Thanks to all who made this possible!

Willem.
Title: Re: Bo Hansén DI layout
Post by: justanalogue on August 02, 2010, 02:31:44 PM
Another picture...
Title: Re: Bo Hansén DI layout
Post by: mtanttar on August 09, 2010, 05:21:52 PM
Hello,

had to register to this forum because I'm currently working on two of these. I'm using Lundahls, and the rest of the parts will be the best available. I just etched the PCB's, drilled the boxes and assembled all mechanical parts. I will post pictures of finished units as soon as I have time to complete them. Lundahls are easily available here in Finland for reasonable price.

If some of you have troubles getting Lundahls I could possibly help, just PM me.

Regards,

Matti, Finland
Title: Re: Bo Hansén DI layout
Post by: jeid on August 12, 2010, 08:36:57 PM
Hello,

Got my boards home from Gustav and had a friend of mine put together the DI for me, he's way better at this kind of thing.

I've got a slight problem with my one. Every once in a while it starts making a grumbling noise, it's as if someone is adjusting a really dodgy pot. I can probably capture a sound clip of it in action. It doesn't do it the whole time, but it happens often enough for it to become an issue. I intend to use this for DI'ing guitars whilst recording, so noise is not an option, especially since I plan to re-amp the DI signals.

Has anyone had this problem.

I dunno if this makes any difference, but my jack sockets are plastic with a metal bolt. Could this be causing me issues?

Cheers for any responses
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on August 13, 2010, 07:17:15 AM
Jeid,

I will try to help you.

First, do you have a good phantom power from your console/preamp ?

What transistors and componets have you use, have they right value ?

Have put in all transistors, diodes and electrolytic in right direction ?

Have you build the box, connectors and grounding after my instructions ?

Can you post a photo on the ready pc-card.

--Bo
Title: Re: Bo Hansén DI layout
Post by: jeid on August 13, 2010, 07:48:27 AM
Hi Bo, Thanks for the quick reply.

Yep, I've got a good phantom power source. Tried it from both interfaces and still getting the same issue. I bought all of my parts from Banzai so I can't be 100% sure of the quality. I'm using a Lundahl transformer. I never built the DI, but I trust the person who made it knows what he's doing. I used the parts list for the values and put them on Gustav's board.

I got the box from Banzai also and it does seem like a tight squeeze, but nothing is touching anything it shouldn't be.

I'll get a picture up yep.

I had a Marshall amp once which made a similar noise and it was a dry solder joint. I wonder if this is the same issue?

I should say, that the clarity from the DI is amazing, makes my Pod Farm tracks so much better! Great work.

Here's the picture.

Cheers
Jeid

(http://i209.photobucket.com/albums/bb223/jeid2000/CIMG5846.jpg)
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on August 13, 2010, 02:53:55 PM
Jeid,

The pc-card looks good, but the first I see was the not isolated tele jacks, and also not shorted input jack when it is not plugged in.

If the buzz noise can be heard when you use the DI-box with a connected amp, it can be the not isolated jacks.

If the "ground loop suppressor" shall work ok, you must use plastic jacks (Cliff plastic or Rean brands) that have both thread and nut in isolated plastic.
Or, you can use those you have with isolated washers, that is a option fot those jacks you have.
When you use safe grounded mains operated amps or other equipments connected with the DI-box together with a mixing console or preamp, you can get ground-loops or buzz noise.

If the buzz noise can be heard when you not have anything plugget on the input jack, it can be the not shorted jack.
There are a extra solder tag on the jack, that can short the tip to ground when not anything are plugged. (see the schematic)

Mybee this can be your problem ??

BTW, if not LED are used on the box outside, you can link (short) the two holes on the pc-card.

--Bo
Title: Re: Bo Hansén DI layout
Post by: jeid on August 13, 2010, 08:01:01 PM
Hi Bo, Thanks again for replying.

I've gone and ordered a couple of isolated jacks.

(http://i12.ebayimg.com/05/i/08/ec/d5/82_1.JPG)

Which are isolated.

So I should ground the tip of the input jack?

I've not been using an amp along with it yet, just plugging my guitar into the DI box and then going from the DI into my Pro Tools interface. I'll try these jacks out. If you can let me know about the tip, I'll be very grateful. I appreciate your help :)
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on August 14, 2010, 07:55:52 AM
Jeid,

Ok, you have not use any amp together with the DI-box, so it is not any ground loop problem, but change to the isolatded jacks, they are better.

No, you shall not ground the tip of the input jack, this is +/hi as normal, but the other solder tag that is the "brake switch" shall go to ground solder tag on the jack.

But you hear the buzz noise even when the guitar are jacked, so the problem is not the shorted input jack, but do this anyway, so everything conform with my schematic.

I will try to explain,
In the top end on the jack you have two solder tags, one is the tongue that will lift when you put in the tele-plug, and this is the normal +/hi tip connection. the other lug is the brake switch solder tag, and shall go to ground, the rear "tongue solder tag", the ground connection to the card.

If you use the new plastic jacks, don´t forget to ground the metal box to the pc-card "chassis" connection point.
Use a solder tag on one of the mounting screws for the XLR connector, for safe box connection. (or a separate screw, solder tag and nut)

Try also to change the input transistor BC550C, because even a new transistor can have a fault like noise or other thing.
If not this will help, try the other transistor BC560C, or the two zenerdiods on the input.

--Bo
Title: Re: Bo Hansén DI layout
Post by: mtanttar on August 14, 2010, 02:14:58 PM
One unit with Lundahl 1538 completed:

(http://wellamoinen.net/DI.jpg)

I used only the best parts I could find. Metal film resistors, polypropylene capacitors etc. Switchcraft jacks are insulated from the chassis with insulating washers. I self-etched the boards.

Thanks Bo and Soeren for this great design.

Btw. In the original schematic all electros are marked 35 volts. Is this enough? Just thinking because my 100u/100V electros just run out and I have some marked 50V.
Title: Re: Bo Hansén DI layout
Post by: gemini on August 15, 2010, 01:30:22 AM
Bo, how about using cinemag trafo? Anyone has try it?
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on August 15, 2010, 07:41:36 AM
mtanttar,

The internal voltage is only 24 volt, so everything from 35 volts an up is ok to use.

gemini,

You can use all brands and types of a good 1:5 mike-transformer, and Cinemag have some nice types that can work very well in this DI-box circuit.

We have talk before about transformers, see this link:
http://www.groupdiy.com/index.php?topic=36569.msg482959#msg482959

Note, if you mount a transformer outside the pc-cart, you must isolate the transformer case from the metal box, because the transformer case/ground shall only be connected to the pc-card electroninc ground.

A other thing,

Some of you use different colour on the LED, but use only red colored LED´s, because this have lowest voltage drop, and gives the highest internal voltage.

--Bo

Title: Re: Bo Hansén DI layout
Post by: jeid on August 15, 2010, 12:20:42 PM
Jeid,

Ok, you have not use any amp together with the DI-box, so it is not any ground loop problem, but change to the isolatded jacks, they are better.

No, you shall not ground the tip of the input jack, this is +/hi as normal, but the other solder tag that is the "brake switch" shall go to ground solder tag on the jack.

But you hear the buzz noise even when the guitar are jacked, so the problem is not the shorted input jack, but do this anyway, so everything conform with my schematic.

I will try to explain,
In the top end on the jack you have two solder tags, one is the tongue that will lift when you put in the tele-plug, and this is the normal +/hi tip connection. the other lug is the brake switch solder tag, and shall go to ground, the rear "tongue solder tag", the ground connection to the card.

If you use the new plastic jacks, don´t forget to ground the metal box to the pc-card "chassis" connection point.
Use a solder tag on one of the mounting screws for the XLR connector, for safe box connection. (or a separate screw, solder tag and nut)

Try also to change the input transistor BC550C to a, because even a new transistor can have a fault like noise or other thing.
If not this will help, try the other transistor BC560C, or the two zenerdiods on the input.

--Bo

Hi Bo, Thanks again for your reply. I'm struggling a little with your English, but I think I get what you're saying. I'll wait for the new jacks to come home this week and see if they make any difference.

I've managed to record the noise that the DI has been making and attached a link to the file. Get a pair of headphones or some loud speakers to hear it. It's visibly and audibly creating noise on the track.

https://dl.dropbox.com/u/3526809/Audio%201_01.wav

When I unplug the guitar the noise disappears and when it's plugged back in, it stays away for a little while then comes back. I've tried this with a few guitars now as a trouble shooting exercise and it's not the guitar I'm using.
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on August 16, 2010, 09:34:22 AM
Jeid,

Yes, I know that I write extremely bad and funny English, especially when I shall explain difficult things.
But I think it has become my signature on various forums around the world.
I am sure that with a little imagination and patience, you will understand what I mean.

Yes, I have listened to your audio clips, and I think it can be one of the transistors, so as I wrote in my last replay to you

Try also to change the input transistor BC550C, because even a new transistor can have a fault like noise or other thing.
If not this will help, try the other transistor BC560C, or the two zenerdiods on the input.


On the picture I can not see what type of 0,1 uF capacitors you have use,
it is non-polarised polyester types, and not some kind of electrolytic with higher value ??

--Bo
Title: Re: Bo Hansén DI layout
Post by: jeid on August 17, 2010, 09:40:44 AM
Hi Bo, thanks for replying again. Haha, your English is indeed funny. You should hear me speak it though. Being from Scotland, it can be rather amusing!

I've decided to scrap the parts in the project and replace them with the ones listed in the parts list on the first post of this thread. I bought all of these parts about three months ago before I saw that list. I don't think I got the right type of parts before.

I'm planning on using the other PCB I have to make another DI. For the extra money, it's worth it. I'd never use two at the same time, but there's nothing wrong with having one spare.

How do you find the Lundahl compared to the Haufe transformer? I'm sorry if you've been asked that before.
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on August 17, 2010, 11:17:37 AM
Jeid,

Haufe ST-8456 is a very nice transformer, but Lundahl LL-1538 is a bit better, and LL-1538XL (extra lardge) have a bit more headroom in the low end.

--Bo
Title: Re: Bo Hansén DI layout
Post by: benlindell on August 19, 2010, 03:14:40 PM
Hey guys, I got the last part I was waiting on put in and finished my first one up. I got the Haufe Transformer in this one and an OEP one on the way. Here's some pics and I'm gonna take some bass samples of it and compare it to other DIs too.

I made mine without isolated guitar jacks and it's totally noiseless!! I think it sounds great too.

(http://www.benlindell.com/diy/Bo-DI/Bo-DI1.jpg)
(http://www.benlindell.com/diy/Bo-DI/Bo-DI2.jpg)
(http://www.benlindell.com/diy/Bo-DI/Bo-DI3.jpg)
(http://www.benlindell.com/diy/Bo-DI/Bo-DI4.jpg)

Some Sound Clips, I'll update these with more later:
http://www.benlindell.com/diy/Bo-DI/Bass-002.wav (http://www.benlindell.com/diy/Bo-DI/Bass-002.wav) - Straight into my 002
http://www.benlindell.com/diy/Bo-DI/Bass-Redeye.wav (http://www.benlindell.com/diy/Bo-DI/Bass-Redeye.wav) - Little Labs Redeye
http://www.benlindell.com/diy/Bo-DI/Bass-Bo-Haufe.wav (http://www.benlindell.com/diy/Bo-DI/Bass-Bo-Haufe.wav) - Bo Hansen's DI with Huafe Transformer

These are my 5 string Lakland on the bridge pickup and no eq.
Title: Re: Bo Hansén DI layout
Post by: Jarno on August 19, 2010, 04:39:12 PM
Very nice definitely adds it own colour and "thickness" of the higher notes, nice build too!
Title: Re: Bo Hansén DI layout
Post by: bdubya on August 20, 2010, 11:06:52 PM
"I made mine without isolated guitar jacks and it's totally noiseless!!"


I noticed that you didn't ground the "chassis" pad on the pcb to the chassis, maybe avoiding the potential ground loop between it and your phone jack grounds?  Nice build, is that a hammond enclosure?  I dig it.


ben
Title: Re: Bo Hansén DI layout
Post by: benlindell on August 21, 2010, 12:37:10 AM
Yeah it's a 125b size that i jb welded the screws and standoffs inside. Got it from pedalpartsplus.com for like $8.

I'm not sure why there's no ground issues but i like it. I'll finish my oep one tomorrow and post more sound clips
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on August 21, 2010, 10:06:00 AM
Guys

As I have said many times before, this DI box has no ground lift switch.
Instead, it has a circuit that automatically protects from ground loops when the DI-box is connected together with guitar amplifiers/mains connected pedals and in same time connected to a mixing console or preamp.
(and all equipment also are connected to mains saftey ground/earth)

If this ground system shall work properly, the jacks must be isolated from the metal box, and the box shall be grounded in the pc-card "chassis" point.
(use plastic jacks, brands as Cliff Plastic or Rean)

If you do that, the ground system are very safe in all situations.

Of course, if you never will use the DI-box togheter with guitar amps or mains connected pedals, the metal jacks are ok, and you have no problems with ground-loops, buzz or noise, because in this case it is only the console or preamp that is connected to the mains saftey ground/earth, and there are no ground-loops to deal with.

--Bo
Title: Re: Bo Hansén DI layout
Post by: benlindell on August 27, 2010, 03:30:05 PM
I finished two more today with a nice red satin casing. I ordered some nylon washers to isolate but in testing at home I haven't had any ground problems with normal jacks, but I take it there is a safety issue so I'll put the nylon in there once they get here.

I also posted up 5 comparisons using my DSI Tetra to get some top and bottom going through these. Much easier to notice the differences. http://blog.benlindell.com/?p=287 (http://blog.benlindell.com/?p=287)
Title: Re: Bo Hansén DI layout
Post by: bdubya on August 27, 2010, 11:34:55 PM
The only time that you might experience problems with using non-insulated jacks is when you're using the DI with a mains-powered pedal and/or amp.  You'd want to connect that chassis ground point all the same, but that's what Bo's been driving at, if I may be so bold: the insulated jacks are necessary for the circuits' ground isolation scheme to work as it's designed to do.  So, if you didn't do it, took it to a live show where there's some potential for ground loops, and plugged it in, you might have a hum-filled night.  If you're using it to DI instruments in the studio straight into a mic preamp without running back out into an amp . . . no worries.
Title: Re: Bo Hansén DI layout
Post by: jeid on August 28, 2010, 12:49:05 PM
Hey Bo, just an update, got the new parts and fitted them(I replaced all of the resistors, capacitors and the two jacks) and I'm getting no buzz now.

Ordered another case and parts so I could make another DI. Thanks for your help. I really appreciate it.
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on August 28, 2010, 02:49:09 PM
Jeid,

Nice to hear that everything works as it should do now.

Benlindell and other

It is not necessary to use shielded cable between PC card and connectors.
Use normal thin "hook-up" wire that can be twisted in pairs.

--Bo
Title: Re: Bo Hansén DI layout
Post by: dandeurloo on August 30, 2010, 12:20:08 AM
Hey guys does anyone have sound samples of the Haufe ST-8456 and the Lundahl LL-1538 like Ben did.  From Ben's audio files I like the Haufe but I would love to hear the difference between those and the lundahls before I decide.

BTW, Ben thanks for the files.  It sold me on the project.  I liked the sound of this build better then the other DI's you compared to. 

Thanks
Title: Re: Bo Hansén DI layout
Post by: gemini on September 02, 2010, 09:28:35 PM
anyone use amplimo trafo in this project?
Title: Re: Bo Hansén DI layout
Post by: Jarno on September 03, 2010, 09:53:55 AM
I was under the impression they just had mains toroids, but they have signal transformers as well, pretty expensive though (like all of their stuff)!
No experience with signal or output transformers from them (mains however....).

80 euros for a 20dBm transformer that costs 14USD at Edcor? Hmmmmm..
Title: Re: Bo Hansén DI layout
Post by: Chrome Heart on September 08, 2010, 10:10:58 AM
Whats difference between the OEP A262A3E and the A262A3C? I looked at P-towns website and the version "C" is the only one he stocks. I cant seem to find a data sheet for the "C".
Title: Re: Bo Hansén DI layout
Post by: Hank Dussen on September 08, 2010, 01:02:58 PM
Probably the canned version.
Title: Re: Bo Hansén DI layout
Post by: Chrome Heart on September 10, 2010, 11:06:40 PM
Probably the canned version.

Thanks Hank. Anyone know for sure?
Title: Re: Bo Hansén DI layout
Post by: benlindell on September 11, 2010, 01:34:29 AM
95% sure it's the canned version
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on September 11, 2010, 09:37:19 AM
Yes, it is a canned version.
See this link:
http://www.oep.co.uk/products_listing.php?page=2&cat=6&subcat=22&subsubcat=47

I have not tried, but hope that there is space for it on the PC-Card.

BTW, I have updated my DIY page with more tips and information on the DI-box construction.  www.hansenaudio.se/techpage.htm

--Bo
Title: Re: Bo Hansén DI layout
Post by: Chrome Heart on September 12, 2010, 05:20:58 PM
Yes, it is a canned version.
See this link:
http://www.oep.co.uk/products_listing.php?page=2&cat=6&subcat=22&subsubcat=47

I have not tried, but hope that there is space for it on the PC-Card.

BTW, I have updated my DIY page with more tips and information on the DI-box construction.  www.hansenaudio.se/techpage

--Bo

Thanks for the link Bo. I guess when the PC boards arrive Ill check the data sheet dimensions against the transformer footprint. Has anyone put the canned OEP in a 125B enclosure?
Title: Re: Bo Hansén DI layout
Post by: Tweekhead on September 12, 2010, 09:47:11 PM
Bo,

Thanks for the great project! The DI sounds fantastic! I went with the Lundahl LL1538 and I'm very, very pleased with the out come.
The only thing I messed up was the size of the enclosure, so I have to order something a bit bigger tomorrow ;D I just did a quick a/b with my Countryman and while both sounded great, the 1975 workhorse sat nicer in the mix, and had a nice round sound to it.

Extra special thanks to bdubya for suggesting the project to me too!

Thanks,

Arthur
Title: Re: Bo Hansén DI layout
Post by: minor_glitch on September 15, 2010, 05:16:15 AM
Hey, I'm ordering parts based on benlindell's BOM, and it seems the .1uf capacitor (505-MKS2.1/63/10) is on backorder at Mouser.  
I'm fairly new to the whole DI game so forgive the stupid question, but is there an alternative capacitor I could order from Mouser?
Title: Re: Bo Hansén DI layout
Post by: Tweekhead on September 15, 2010, 09:11:49 AM
Correct me if I'm wrong, but I was told can just go with a higher voltage as long as it's the same value. Mouser part number 505-MKS2.1/250/5 should work.
I actually built mine with mouser part number 505-MKS2.1/63/10 and although they were smaller than the recommended hole spacing I just bent the leads.

Title: Re: Bo Hansén DI layout
Post by: minor_glitch on September 15, 2010, 10:53:30 AM
Thanks! 
I have one last question.  They also have one that is .1uf 63v, but the tolerance is 5% instead of 10%. Would that make any significant difference or would it be better to go with the 250v version?
Title: Re: Bo Hansén DI layout
Post by: Tweekhead on September 15, 2010, 11:03:32 AM
I'm sure the 5% or 10% will be fine, just check out how big the foot print is. Again, correct me if I'm wrong, but the % is the amount of deviation the part could have from the spec'd value.
Title: Re: Bo Hansén DI layout
Post by: minor_glitch on September 15, 2010, 11:09:08 AM
Makes sense to me.  Thanks for your help.
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on September 15, 2010, 11:37:22 AM
You can read on my www.hansenaudio.se/techpage.htm about component choices.

This 0,1uf capacitor can be any brand or type that is a plastic film type with 5 mm space between legs and can handle about 25 volts and up.

I have recommended 63 volts because this is a standard voltage of proper physical size of this capacitor.

--Bo
Title: Re: Bo Hansén DI layout
Post by: dandeurloo on September 19, 2010, 10:19:29 PM
Bo, I am almost done with 2 of your DI's!  I just have a few questions about the grounding?

1.  Should I connect pin 1 of the xlr to the tab of the xlr body so that the actual xlr is grounded to the case?  I know I need to make sure that the ground on the pcb is connected to one of the screws that holds on the xlr!  So that will be done.

2.  what is the shorted input jack?  How is that done?


Thanks
Title: Re: Bo Hansén DI layout
Post by: dandeurloo on September 20, 2010, 06:08:00 PM
Just finished the 2 DI's and they both sound great.  Thanks for the project!

I have 2 more boards and I'm not sure what transformers I will use for them.  I have a UTC o-28 maybe that and something else?

FYI, I did connect the chassis tab on the xlr to pin 1 on the xlr and I ran the chassis wire from the PCB to the screw holding the xlr in place. No noise!

Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on September 21, 2010, 07:59:01 AM
Dandeurloo,

Yes, the XLR ground tab and pin 1 shall be connected together, but also secure on one of the XLR fasten screew, and from same point also connected to the pc-card chassis connecting point.

Shorted input jack can you read about on my web site www.hansenaudio.se/techpage.htm

--Bo
Title: Re: Bo Hansén DI layout
Post by: justanalogue on October 03, 2010, 04:22:09 PM
Finished the remaining 3 DI's and used them this week end for tracking of various stuff.
Silent, and basically no color, very very happy with them.

Another big thanks to Bo and all who participated in this project.

Kind regards,

Willem.
Title: Re: Bo Hansén DI layout
Post by: Holger on October 06, 2010, 11:03:50 AM
(Doesn't this belong to the lab, BTW?)

So, my version, powder coated front panel, case is from Modushop, special build for a buddy hence the special humor  ;)

(http://audiofor.tv/diy/dibox/front.jpg)

(http://audiofor.tv/diy/dibox/front2.jpg)

(http://audiofor.tv/diy/dibox/guts.jpg)
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on October 06, 2010, 11:26:55 AM
 :D :D :D
I don't know Herr oder Frau Küver,
but you did a nice work as always!
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on October 06, 2010, 11:53:34 AM
Willem & Holger, verry nice metall work.

Willem:
If you not use the LED for the outside, it is better to do a link in the place for the LED.
If you use the LED, use only a red colour because this have the lowest voltage drop.

Holger:
Have you use normal diodes instead for zener diodes for the input protection, or is this black (1N4004 style) diods 12 volts zener ??
Use the short link on the input jack, you can read about it on my tech page www.hansenaudio.se/techpage.htm

--Bo
Title: Re: Bo Hansén DI layout
Post by: Holger on October 06, 2010, 12:07:12 PM
Thanks for liking...
Bo, it's the black 1N400x style zener.
Thanks for the reminder regarding pin to ground.
Title: Re: Bo Hansén DI layout
Post by: justanalogue on October 07, 2010, 04:11:07 AM
Hello Bo,


thanks for the kind words, would it improve, sonically, when I remove the LED?

Kind regards,

Willem.
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on October 07, 2010, 12:01:35 PM
Willelm,

It makes no difference for the sonically quality, but since the LED are connected in series with the internal voltage supply, the headroom will reduce if the LED have too high a voltage drop.

Red LEDs have the smallest voltage drop, but other colors are much higher.

If no LED is used on the outside, it is unnecessary to sit and glow by itself on the inside.
In this case, make a link and save some headroom.

--Bo
Title: Re: Bo Hansén DI layout
Post by: justanalogue on October 07, 2010, 12:36:31 PM
Dear Bo,

all clear, thanks for the explanation.

Willem.
Title: Re: Bo Hansén DI layout
Post by: minor_glitch on October 14, 2010, 11:57:21 PM
Here's a REALLY rookie question. 
I'm probably going to get the hammond box Bo recommends on his page (1590-TBK).  How easy is it to drill holes in these boxes?  I haven't dealt with metalwork before and I only have a regular old handheld power drill.  Am I as screwed as I think I am?
Title: Re: Bo Hansén DI layout
Post by: ChrisPbass on October 15, 2010, 07:31:34 AM
Here's a REALLY rookie question.  
I'm probably going to get the hammond box Bo recommends on his page (1590-TBK).  How easy is it to drill holes in these boxes?  I haven't dealt with metalwork before and I only have a regular old handheld power drill.  Am I as screwed as I think I am?

The die-cast hammond boxes are pretty easy to drill minor-glitch. Just take your time marking out the layout (use masking tape to protect the finsh), use an automatic centre punch or if you don't have one then be very careful using a normal one as it is easy to crack these boxes by being too heavy handed with the hammer. Use a small drill first to keep the layout accurate, then work up in size till you get to the correct diameter hole. For holes bigger than 13mm, you may need a step drill or hole saw or be prepared to get busy with a file. I often write on the masking tape what size the hole is so I don't forget and end up drilling it too big!
 
The main problem is securing the box when drilling, so it would be useful if you can mount it in a vice or workbench etc (don't over-tighten or it will crack and be carefull you don't mark the finish). The last thing you want is this spinning around on the drill bit and causing chaos.
People may disagree, but when I haven't had access to a vice or similair, I've always been ok holding the box between my feet (work boots on) and being extra careful with the speed of the drill, but don't try this unless you are very confident in your abilities.

If you can get access to a pillar drill or buy a cheap drill stand then this will help with keeping things accurate, but if you are carefull and take your time, you can get very good results. The most important thing is that the DI works so construction first, asthetics second in my book.



Title: Re: Bo Hansén DI layout
Post by: minor_glitch on October 15, 2010, 07:14:01 PM
Thanks for the info! It sounds like something I can handle.  We'll see how it goes...
Title: Re: Bo Hansén DI layout
Post by: minor_glitch on October 27, 2010, 04:22:10 PM
Finished mine.  It doesn't look to fancy but that's alright.  The metal work was the hardest part due to my lack of proper tools.

I think I did ok for my second DIY project.  My first one was the VP26, so this was a great second project!  I posted a bunch of photos on my blog if anyone is interested:  http://minor-glitch.livejournal.com/7775.html (http://minor-glitch.livejournal.com/7775.html)

I have a friend dropping by with a guitar next week, so I won't know how it sounds until then.  Let me know if you spot any errors.
Title: Re: Bo Hansén DI layout
Post by: warpie on October 29, 2010, 08:28:48 AM
guys, would you be kind enough to bear with me for a sec?  :)

1) I know this has been discussed extensively but I'm a bit confused regarding the isolation and the 'switch' thing when the jack is disconnected? Will any of these 2 do the job I need?
http://www.banzaimusic.com/Jack-MO-PCB-SW.html
http://www.banzaimusic.com/Jack-MO-LUGS-ECO.html

2) Pad Mod: what type of cap is best for the 18pF?

3) Can BC109C and BC214 be used as alternatives? (I think the answer is 'yes' but I'd like to confirm that)  :)

thanks for this project  :)
w.
Title: Re: Bo Hansén DI layout
Post by: gyraf on October 29, 2010, 09:50:07 AM
(..Bo himself is currently locked out of this forum - the new software doesn't like his name, specially the e-with-a-dot-over messes up. Even this thread's title is messed :-) . He should be back when we get this fixed...)
Title: Re: Bo Hansén DI layout
Post by: bpucekov on October 29, 2010, 11:21:11 AM
1) both
3) yes
Title: Re: Bo Hansén DI layout
Post by: warpie on October 30, 2010, 10:10:39 AM
1) both
3) yes

cool, thanks  ;D
Title: Re: Bo Hansén DI layout
Post by: warpie on October 31, 2010, 05:13:53 PM
one more question regarding the LED...

I know it needs to be red but does the physical size affects the voltage drop?
For example, a 3mm LED has smaller voltage drop than a 5mm LED?
Is this the reason is preferred/suggested by Bo, or it doesn't really matter?

thanks
w.
Title: Re: Bo Hansén DI layout
Post by: minor_glitch on October 31, 2010, 11:22:16 PM
I know it needs to be red but does the physical size affects the voltage drop?
For example, a 3mm LED has smaller voltage drop than a 5mm LED?
Is this the reason is preferred/suggested by Bo, or it doesn't really matter?
Yeah, I think this is one of those rare cases when smaller is better. 
It would make sense that a larger LED would result in a greater voltage drop.  I'm sure it would work, but it would be an unnecessary sacrifice.
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on November 01, 2010, 03:48:30 PM
Sorry, I have not had the opportunity to answer your questions in a while, because there ara a problem with the forum server that not accept the characters in my user name longer.
But now I have changed my username temporarily,  So now I'm back in place again.

Warpie,
The important thing is that the LED is red, so a 5 mm. is ok.

Use a ceramic 18 pF capasitor

And as bpucekov say, both plastic jacks is ok, and BC109C as NPN and BC214B/C as PNP is also ok.

--Bo
Title: Re: Bo Hansén DI layout
Post by: warpie on November 02, 2010, 07:14:16 AM
thanks for your help guys!  :)

Bo, good to hear you managed to logged in  :)
Title: Re: Bo Hansén DI layout
Post by: warpie on November 03, 2010, 07:34:44 AM
by the way I found this enclosure that seems to fit OK the 1538 TX. However, I'm not 100% sure yet as I haven't calculate the exact dimensions.

http://cgi.ebay.co.uk/Aluminum-Project-Box-Enclosure-Case-Electronic-DIY1204-/300376690143?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item45efd88ddf#ht_2577wt_907

Anyone has experience with the specific box?

It looks nice, robust and I think is pretty cheap.
My only concern is the color. I really like it but I'm not sure if it'll survive after drilling and engraving but I suppose this applies to all painted enclosures...
Title: phoenix from the ashes
Post by: wowi on November 07, 2010, 07:00:46 AM
I just finished 2 Di Boxes in a Thomann millenium DI
Title: phoenix from the ashes
Post by: wowi on November 07, 2010, 07:19:17 AM
I just finished 2 DI Boxes in a Thomann Millenium DI-E case.

This is, what you get from Thomann for 9,90 Euro

(http://farm5.static.flickr.com/4147/5154120000_4f38e33d27.jpg)

the inside

(http://farm2.static.flickr.com/1332/5153513605_b6953c5781.jpg)

Just throw everything away (keep the connectors and the switches) and cut off the brackets of the old transformer

(http://farm5.static.flickr.com/4149/5153513725_b0cbff8ea2.jpg)

Now you can fill the space with Bo's populated DI Board (The transformer is the Haufe ST8456 from Volker)
and drill a little hole for the LED

(http://farm5.static.flickr.com/4053/5153513869_05f40a314d.jpg)

Finaly cover the ugly surface from thomann with a nice label

(http://farm5.static.flickr.com/4013/5153514017_e49db65c26.jpg)

And here is the "Soul-Box"

(http://farm5.static.flickr.com/4125/5154120722_38d8a2625b.jpg)

There are two switches, you can use for a 20db Pad and a ground lift if you want.

Thanks Bo - Nice weekend
Wolfgang
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on November 07, 2010, 07:41:29 AM
sweet ;D ;D ;D
think I need to order soon from Aldi Sued ;)
Title: Re: Bo Hansén DI layout
Post by: Holger on November 07, 2010, 08:32:49 AM
wowi, that's really a good idea  :D
Title: Re: Bo Hansén DI layout
Post by: wolan42 on November 10, 2010, 04:45:16 PM
Okay,

after reading the treat and having the necessary of two DI Boxes, I ordered two PCBs from Gustav.
And here is the first one. (The first realy finished DIY by me. Some other not finished DIY projects laying around: Pultec, GreenPre, GSSL, LA4A ...)

Build it with a Beyer TR/BV 352 007 004, which i shot on eBay.
Than ordering the frontpanel from Frank (I like his work).
The neutrik sockets laying around here for some years, and there were no necessary to buy cheap sockets. ;)
Also the enclosure.

After the first test with a Tascam  FM 1804 I love the sound. Okay the ratio is 1:7 and so I must open the gain pot. (sorry about my english. I'm not in practice for a long time).

For the second one I will try an old 75101-1 (Pre-Cinemag?).
I will need both for acoustic guitars with buildin piezo pickup.

Thanx to Bo, Soren, Gustav, Frank and for all the hints in this forum.

Andreas

(http://img248.imageshack.us/img248/756/bodi3.th.jpg) (http://img248.imageshack.us/i/bodi3.jpg/)

(http://img248.imageshack.us/img248/3577/bodi2.th.jpg) (http://img248.imageshack.us/i/bodi2.jpg/)


Title: Re: Bo Hansén DI layout
Post by: ChrisPbass on November 10, 2010, 08:14:39 PM
Finished mine.  It doesn't look to fancy but that's alright.  The metal work was the hardest part due to my lack of proper tools.

I think I did ok for my second DIY project.  My first one was the VP26, so this was a great second project!  I posted a bunch of photos on my blog if anyone is interested:  http://minor-glitch.livejournal.com/7775.html (http://minor-glitch.livejournal.com/7775.html)

I have a friend dropping by with a guitar next week, so I won't know how it sounds until then.  Let me know if you spot any errors.


Good work MG  :) Any thoughts on sound characteristics?
Title: Re: Bo Hansén DI layout
Post by: lpkyer on November 13, 2010, 01:49:22 AM
Hey just to let Mr. Hansen know that we did 22 of his DIs here in a Montreal college for a mid-term soldering project. Each student had to buy a nice OEP xformer so they came out great sounding !
 :D

Tack !
Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on November 13, 2010, 10:47:32 AM
Ipkyer,

Great to hear, 22 pieces of my DI-boxes, I am honored that you did this as a soldering project at college.
It would be fun to see a group picture of all these.

--Bo
Title: Re: Bo Hansén DI layout
Post by: minor_glitch on November 13, 2010, 11:49:24 PM
So that explains why diypartssupply.com is out of a262a3c's!
Title: Re: Bo Hansén DI layout
Post by: kante1603 on November 14, 2010, 11:32:54 AM
Hi there,

have built two of them with HAUFE-transformers and i am really happy with them:True workhorses :)
Thanks to all of you for this build,especially Bo,Soeren and lunytune,Gustav and Volker at silent arts!

Best regards from germany,

Udo.
Title: Re: Bo Hansén DI layout
Post by: kante1603 on November 14, 2010, 02:10:43 PM
...and some pics...
Hope it works-never done this before-excuse me when it fails!
(http://img242.imageshack.us/img242/1661/twins1.jpg) (http://img242.imageshack.us/i/twins1.jpg/)
(http://img821.imageshack.us/img821/5158/profil1q.jpg) (http://img821.imageshack.us/i/profil1q.jpg/)


(http://img255.imageshack.us/img255/997/inside2.jpg) (http://img255.imageshack.us/i/inside2.jpg/)
(http://img686.imageshack.us/img686/9401/pcbpopulatedjacks.jpg) (http://img686.imageshack.us/i/pcbpopulatedjacks.jpg/)



Cheers,

Udo.


Title: Re: Bo Hansén DI layout
Post by: sverige_cruz on November 17, 2010, 01:38:48 AM
(http://lh4.ggpht.com/_EHQRT0x3gro/TON1g5CZDaI/AAAAAAAAANk/KsMSW0vsA-c/s400/complete.jpg)

Just finished another - my other has an OEP xfmr, this one a UTC A-21 that has been getting dusty. I know the impedance match is not "to design", but I figured I'd build it and find out if it works (well). It does.

Compared to the OEP, this one is darker - I kinda like it better, but I'm into old thuddy bass sounds.

Reused an enclosure, filling the holes with JBWeld.

Thanks again Bo!

Here's some more pics:

http://lh6.ggpht.com/_EHQRT0x3gro/TON1gj7c0ZI/AAAAAAAAANc/wxIUjWkrQG4/box_xfmr.jpg (http://lh6.ggpht.com/_EHQRT0x3gro/TON1gj7c0ZI/AAAAAAAAANc/wxIUjWkrQG4/box_xfmr.jpg)
http://lh4.ggpht.com/_EHQRT0x3gro/TON1gd-Tr0I/AAAAAAAAANY/6FC-Z64Sl-k/box_pcb.jpg (http://lh4.ggpht.com/_EHQRT0x3gro/TON1gd-Tr0I/AAAAAAAAANY/6FC-Z64Sl-k/box_pcb.jpg)
http://lh5.ggpht.com/_EHQRT0x3gro/TON1gn6XpLI/AAAAAAAAANg/bVHey1Jmknc/done_pre_install.jpg (http://lh5.ggpht.com/_EHQRT0x3gro/TON1gn6XpLI/AAAAAAAAANg/bVHey1Jmknc/done_pre_install.jpg)
http://lh4.ggpht.com/_EHQRT0x3gro/TON1g5CZDaI/AAAAAAAAANk/KsMSW0vsA-c/complete.jpg (http://lh4.ggpht.com/_EHQRT0x3gro/TON1g5CZDaI/AAAAAAAAANk/KsMSW0vsA-c/complete.jpg)
Title: Re: Bo Hansén DI layout
Post by: zebra50 on November 17, 2010, 04:11:56 AM
Mine works very nicely too. Thanks for the project.

Anyway, good to see all of this DIY going one! Nice work with that UTC - looks 'old skool'!

Title: Re: Bo Hansén DI layout
Post by: Bo Hansen on November 17, 2010, 02:11:42 PM
Sverige_cruz,

UTC A-21 a very good transformer, but to low impedance on one side to fit this application.
500/600 ohms is a lot to low for the DI-electronics to drive.

Unfortunately there is no suitable transformer in the UTC input series, the closest is the A-39 (Scully 280 mike transformer) configured in 2000 ohms to 150 ohms, but even this have a bit to low impedance on the "Hi-Z side".

There are two UTC inter-stage transformer that might be usable.
A-34 configured 6250 to 125 ohms or 500 ohms.
A-44 configured 4000 ohms to 150 ohms.
These are large transformers that will be good for 1 watt output.
Perhaps it might be worth a try for experimental purposes.

--Bo
Title: Re: Bo Hansén DI layout
Post by: cake on November 19, 2010, 07:26:25 PM
Greetings to all.

I got to say that i was lurking (well, a lot) around here ... but it's time to post.

I don't know of a better place to ask what i want to know, and i also feel i got to share something after all i read here. Well, to start participating at least.

It's not a thread hijack - what i have is four transormers, that i got from a guy here and am speculating of using them for this DI project. I suspect the guy scavenged them out of some mixer, but he couldn't (wouldn't?) tell anything... All i get of them is (almost unreadable) print saying "ET(?) 3603" - that would be my guess, it's pretty much unrecognisable. Also they seem work fine as a passive line to mic - i guess something of a 5:1 rather than a 10:1, but i haven't put them through any kind of test to be sure. I've  just fed line signals (keyboards, aux busses) to mic inputs through them, and they seem to cope fine, with some gain loss ...

Anyone can propose a quick test for me that doesn't include precise signal generator to actually get some numbers about them?
I suppose this is THE place to find guys who know about trafos - so, gentlemen can anyone recognise the suspect?
Thanks a lot.

And thanks for this DI project. I'll be doing this with or without these transormers...
cheers


Title: Re: Bo Hansén DI layout
Post by: cake on November 19, 2010, 07:28:29 PM
Got a side view, also. Phone's there for size reference, but i don't know if  it really helps ...
Title: Re: Bo Hansén DI layout
Post by: cake on November 19, 2010, 07:32:11 PM
Of course, i don't want to be rude. If anyone thinks this question sould have it's own thread just say ... thanks
Title: Re: Bo Hansén DI layout
Post by: flaheu on November 22, 2010, 06:47:51 AM
HI, these looks like Sowter Tx made for Midas pro (old mixer).
Not sure, try too see Sowter site to check.

cheers
Title: Re: Bo Hansén DI layout
Post by: cake on November 23, 2010, 08:47:43 PM
Thanks.
Yes, that's also what i thought - big chance it's a sowter. I went through those lists of their old trafos, but no luck. I just don't have enough data ... these numbers are just not readable enough and when i assume the mark is 3603 that gets me to a sowter which was a 600 ohm 1:1. And this one definetly isnt 1:1. It definetly brings signal down (didn't wire it up in reverse). Very likely this one's a mic input - 1k or 2k primary, 200ohms secondary, but i'm going to check that more precisely  when i get a signal generator.

Could this one be an OEP? I can't find any reference for older OEP products...
Title: Re: Bo Hansén DI layout
Post by: alexc on November 24, 2010, 06:25:21 AM
You could apply a sig gen output of 1V peak-peak or so at a useful frequency, say 1KHz and
measure the output voltage on an oscilloscope (could be a PC based or a standalone one).

That will give the turns ratio.

Use a multimeter to determine which pins have coils between them by applying
the continuity checker very briefly.

Measure the dc resistance of the coils, again by applying the multimeter resistance checker
briefly (so as to reduce the risk of magnetising the transformer core and thereby increasing likelyhood of core saturation)

Multiply the dc resistance by 10 for a rough estimate of the coil impedance.

That's the simple and crude way to characterise the traffo.
Title: Re: Bo Hansén DI layout
Post by: [silent:arts] on November 24, 2010, 08:23:08 AM
finished mine today ;)

(http://www.silentarts.de/DIY/temp/IMG_6038.jpg)

(http://www.silentarts.de/DIY/temp/IMG_6041.jpg)

thank you Bo, Soren & Luny Tune.
thanks to wowi for the Aldi-Sued case tip,
and thanks to Frank for his great engraving service.
Title: Re: Bo Hansén DI layout
Post by: cake on November 25, 2010, 04:29:41 AM
Hey alexc, thanks for the tips!

i got this with my DMM, on the first trafo of the four:

- one coil measures 1325, the other 37;  times ten, is it what it looks? a primary of 10k? how sure can i be? i get it it's a rough measurement, but it gets me the region, right?
near (well...) 200 on the secondary. 

i still have to get a signal gen. and check the other three to get a green light use them in this project.

silent:arts - those are great looking boxes!

cheers to all.

 
Title: Re: Bo Hansén DI layout
Post by: Bonke on December 14, 2010, 05:43:38 AM
Here are my two recently finished workhorses! with OEP transformers
They are a bit shabby chic as my wife calls them. :D dont know if that translates
I tried to do the iron on tranfer method for the printing. It turned out to work quite well on the aluminium case. I just wasnt patient enough. But I quite liked the vintage feel of the print so I didnt bother to redo it.

Henrik

(http://web.me.com/bedahenke/Stuff/DI-box_files/IMG_0311.jpg)

(http://web.me.com/bedahenke/Stuff/DI-box_files/IMG_0312.jpg)

Title: Re: Bo Hansén DI layout
Post by: lpkyer on December 15, 2010, 12:09:07 PM
Ipkyer,

Great to hear, 22 pieces of my DI-boxes, I am honored that you did this as a soldering project at college.
It would be fun to see a group picture of all these.

--Bo

 I wish I had taken one at the time (picture), I'll post pictures of some of the finished ones soon though :)
Title: Re: Bo Hansén DI layout
Post by: stefan on December 24, 2010, 02:02:40 AM
I made two of these, My Pedalsteel never sounded this good! thanks Bo.
Title: Re: Bo Hansén DI layout
Post by: joellegros on January 03, 2011, 03:31:11 PM
Hey everyone, I finally finished two of these.  They sound great!  Thanks to Soren and Luny for the layout, and of course to Bo.  : )


http://lh4.ggpht.com/_ytgJgDa8utQ/TSIwE0e-yBI/AAAAAAAADKA/q6mEPknjlow/s576/Bo%20Hansen%20DI.JPG
http://lh4.ggpht.com/_ytgJgDa8utQ/TSIwFtVTXcI/AAAAAAAADKE/WYp2kXjONs4/s800/Guts.JPG

Title: Re: Bo Hansen DI layout
Post by: gemini on January 06, 2011, 09:16:50 AM
Found beyer dynamic transformer TR/BV35864 on eBay. Can it be used for this build?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 06, 2011, 10:59:56 AM
Gemini,

I think this type have very low ratio around 1:1,5, so in this case, it is not usable for my DI-box.

Beyer have some other types that you can try to find:
TR/BV 3.51.0.05.0300
TR/BV 3.52.0.05.0300
TR145/BV35799
TR45/BV35536

Or a other German brand MB/Mikrofonbau (MB-Electronic Gmbh) type 4481

All types have a ratio of 1:5 and fits in my DI box if they are used backwards.
The downside may be that they are quite small and have not very good headroom in the low end.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Slaten on January 14, 2011, 12:41:39 AM
This was my first ever DIY project and have recently just got into electronics.  I completed the project earlier this evening using an OEP AE262A3A tranny and pulled out the DMM to check some final readings.
 
I plugged the DI box into my Presonus M80 and got the red LED to light up on the DI box and plugged my bass into the input.  I got nothing on the channel output level even with gain pegged right!? I used a DDM and took all readings as per Bo's tech page and got 23.6 volts on the positive side of the LED, and then measured 10.96 volts at the junction of the 10uf cap, 3.9k resistor and the emitter lead of the 560C.  So all measurements good. 

What could be the problem?  I used a Cliff UK plastic PC jack that has 4 poles that I pulled off of my old 4 track's  board.  I soldered the + wire to one of the 2 back poles and the other to a front pole.  I dunno, maybe my jack is bad?  Anyone have an explanation?  I'm stumped.  I also check all traces for solder bridges and everything checked out.  Is there anyway to check for voltage going into the board from the bass when I hit a string?  Thanks

Jon

       
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on January 14, 2011, 02:26:07 AM
connect the two front pins and the two back pins of your jack together.
4 poles means normalized / switching.
you might use the switched part at the moment, which isn't connected to the plug if inserted.
Title: Re: Bo Hansen DI layout
Post by: Slaten on January 14, 2011, 04:17:13 AM
Silent:Arts,

Thanks for the reply.  What I did earlier before logging back on here, was just removing the jack and installing a new one from an old Boss effects pedal I never use anymore. Whatever the problem was earlier, was solved with the new jack. Anyway, Bo's DI sounds really good and this was a really fun project.  Bo, thanks a lot for giving us a new tool to make our music sound better.

Jon 
Title: Re: Bo Hansen DI layout
Post by: Slaten on January 30, 2011, 01:59:44 PM
Silent:Arts & Bo,

Hello, I actually decided to build another DI Box because this project was very easy to do and was a lot of fun for me, being a beginner to all of this.  Silent: Arts, I remembered your advice on the proper connection of the Cliff plastic jacks on this new project and obviously your advice was terrific and worked beautifully.  I just have two more questions for you and Bo about (DI Box's in general) and another possible mod. 

The first question is about the amp output jack: Is this a "Bypass out" whereby my bass/guitar(s) signal will still remain a high Z impedance, or will the circuitry change it to low Z?

The other question is:  Can a tube be used in this circuit, or has anyone here on the forum attempted this successfully?  I'm asking this because a friend of mine has all tube gear in his studio and most of his equipment is high-end vintage stuff that he's has since the 1970's and he's quite partial to tube-only gear. 

That's all for now guys.  Thanks for the help and support for this project!  It has been a lot of fun! 

Regards.

Jon Slaten 
Title: Re: Bo Hansen DI layout
Post by: Moses on January 30, 2011, 02:53:12 PM
Im not an expert by any means, but I believe with a small amount of math to find new values, an external power supply, and a significantly higher Vcc (B+) you could rework the circuit as a valve box... But why bother, really? It'll probably be more work than starting from scratch, and it's a very nice sounding DI as is (I have 2 with the Haufe transformers)!

You could build one of the Alembic F2B valve preamps with the same backwards 1:5 mic trafo on the o/p  for a valve solution... There was even a version posted here at one point with negative feedback to reduce distortion and gain... Probably be work out better! I have plans to do this soon, with variable feedback...

Mo
Title: Re: Bo Hansen DI layout
Post by: Gus on January 30, 2011, 04:24:46 PM
I have been searching for the Thomas Holly thread with the phantom powered tube DI using a DC to DC converter for the heater. 
Anyone remember the thread name?   I have not seen a Thomas Holly post for some time.
Title: Re: Bo Hansen DI layout
Post by: pyjaman on January 30, 2011, 07:11:40 PM
Jon,
A tube DI would be a totally different build, you can look for "tube DI" or "tube direct box" , there are quite a few ideas arround there.

regarding your other question, the output jack is not what you call "bypass out" as implemented in some other DIs. it's taken from output of the second transistor, with its fixed output impedance, wich is higher than the balanced output Z, but can't behave exactly the same as a passive guitare pickup coupled straight with the first tube stage of your fav guitar amp.
by the way, you probably can implement such a "bypass out" simply by adding another femal jack in parallel with the input jack. perhapps some resistor values migt be tweeked, I think I remember I have seen this discussed somewhere in this topic...
Laurent.
Title: Re: Bo Hansen DI layout
Post by: Slaten on January 31, 2011, 03:59:08 AM
Yeah I know, I figured that.  I had to just put that out there and see what you guys thought.  I'm a complete novice, so I couldn't do something like that unless it was made available on a vero board.  With the two DI's I completed recently, instead of trying to iron the copied traces to a copper board, I just installed the components on a perfboard and copied the traces exactly by looking at the silkscreen and just slowly ran the .020" tinned wire out exactly like the PCB and soldered it all up. It works perfectly and all DMM checks measured within +- .5 volts.  So I did something right there.  Oh well, hopefully there is a somewhat "simple" tube DI out there somewhere.  Thanks for the advice guys.

Jon Slaten
Title: Re: Bo Hansen DI layout
Post by: Slaten on January 31, 2011, 04:09:04 AM
Pyjamen,

I read through your post several times on what you mentioned about the output jack.  I apologize here because I am trying my best to learn all of the language of electronics, but would you mind saying that again differently.  As you would say to a 6 year old child.  You mentioned this:

"It's taken from output of the second transistor, with its fixed output impedance, wich is higher than the balanced output Z, but can't behave exactly the same as a passive guitare pickup coupled straight with the first tube stage of your fav guitar amp."

Ok Pyjamen, so the signal comes from the 2nd transistor, and this transistor has a "fixed" impedance.  And you mentioned that this impedance is "higher/more than the balanced output Z (the XLR cable).  So are you also saying that it DOES behave the same as a passive guitar pickup?  That means it's HI Z correct, but with more gain?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 31, 2011, 11:47:16 AM
Slaten,

The "amp output jack" as Pyaman say, is a un-balansed output after the amplifier but before the output transformer.
The impedance is a lot lower compare with a passive guitar, so it can drive a long guitar cable with out any problem, and it will not disturb the instrument because it is not connected in paralell with the input jack.

As also mentioned previously,

Replacing the transistors with tubes, is not so practical, reason is that the tubes are working at higher voltages, and also need heating that draws high current.
This is complex to get out of the phantom power from the microphone input.

There are ways to overcome this problem, as Gus was talking about, you can used a "voltage converter" and miniature tubes that use less heater current, or using high frequencey to generate heat for the tube.

But the circuit is totally different, so it is pointless to use my design or circuit board for the same.

It is better to build a circuit with a normal tube cathode follower and run this with a power supply that is connected to the mains outlet.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Slaten on February 01, 2011, 12:00:38 AM
Bo

Thank you for the reply and thoughtful information about your work.  I read about DI boxes on the internet about 3 months ago and realized how important having one in my studio would really benefit me.  I was curious about the "DI Box" and by coincidence, read a post on a forum somewhere and a guy was writing about your box and how great it sounded!  From that moment on, I was on the internet searching for your DI box and how to build one for myself.  I still can't understand how you designed this project and using your knowledge and experience you just created this from an idea you had one day.  I am saying this because I don't know much about electronics and have just recently started to learn about it.   So I will tell my friend that I could build a tube di box in the distant future.  I made 2 of your DI's and that is all I need for recording my Mexican Fender PBass and maybe the Les Paul as a DI and mic'ing it through my cabinet.  I will pass on your information to my friend. Thank you answering my question about the amp output.

Jon Slaten
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 01, 2011, 08:51:47 AM
Jon,

"I still can't understand how you designed this project and using your knowledge and experience you just created this from an idea you had one day"

This design is not "rocket science" it is a very simple basic design, yet perfect for this purpose. (you can read more about it here: www.hansenaudio.se/techpage.htm )


I had work as amplifier designer for 10 years when I did this design, so it was no problem for me.

The idea for it came when I, as a recording engineer had trouble getting a good bass sound.
At this time in Swedish studios, there were mostly self-built passive DI-boxes with very small high ratio mic transformers, and this had poor headroom in the bass and sounded pretty muddy.

--Bo
Title: Re: Bo Hansen DI layout
Post by: helterbelter on February 06, 2011, 04:44:09 PM
The last couple of weeks I had been busy with a bit of home improvement : redo the plasterceilings, added a lot of insulation, new paintjobs, etc.

At last, today I had the opportunity to do :..... Nothing !

So, I built a few boxes for my guitar !
Rossi Re-amper, and a Hansen DI.

I got the boxes from work, they were thrown away, so I grabbed them from the dustbin.  ( I'm all about recycling baby, yeah !  ;D ) I need to have another front for the DI though, that's why the jack entries are so close to eachother. I also have to get a few nice knobs for the pots, what I used is just what I had laying around. Yes, the caps are missing...

Anyway, it just took me 3 hours to build these 2 boxes, including drilling, soldering, wiring. great !
I haven't tested them yet, because my mixing console is down for a week or 2, but there's not much that can be done wrong, right ?

That's a good way to spend your time, right ?
(http://i71.photobucket.com/albums/i126/helterbelter/Rossi%20Hansen%20boxes/HansenRossifront.jpg)

And the insides and backviews can be seen here :
http://s71.photobucket.com/albums/i126/helterbelter/Rossi%20Hansen%20boxes/?albumview=slideshow
Title: Re: Bo Hansen DI layout
Post by: warpie on February 06, 2011, 06:34:33 PM
wow Paul! These are nice boxes. I should had lied to you... haha.
Title: Re: Bo Hansen DI layout
Post by: warpie on February 15, 2011, 06:49:25 PM
Ok I have two questions  :)

I accidentally short pin 1 to pin 3 (for les than a second fwiw) while phantom was on. Is there any chance I destroyed something in my circuit? It seems like it operates normaly but is there anything I should double check (like a cap for example)?

Also, I read that Bo suggests to connect the XLR tab to pin1 and then to the same screw I use for the 'chassis' connection, which is one of the XLR screw in my case. Is this not already done in the PCB? I can see a trace from 'chassis' to pin1 on the PCB.
Also, in Bo's photo the tag is unsoldered from what I can see http://www.hansenaudio.se/big%20box%20inside.JPG

The DI looks to work OK but I'm not sure about grounding/noise issues. I even feel some electricity in my fingers sometimes when I touch the strings. Not sure whether is the DI or the crap lines in my house (I feel the same when I'm touching my macbook pro).
I'll take another DI from the studio to check how it behaves at home. Hopefully I'll figure out if it' the DI or not...

thanks
Michael
Title: Re: Bo Hansen DI layout
Post by: kante1603 on February 18, 2011, 11:40:38 AM



I haven't tested them yet, because my mixing console is down for a week or 2, but there's not much that can be done wrong, right ?

That's a good way to spend your time, right ?



Yes sir!I have built two of the DIs also-with those Haufe-transformers!Believe me:They are awesome!!!
Have checked them in the studio and compared to some others I had arround here,and that means against some expensive types too.What can I say-I think i will never touch the old ones again ;)
Have done a ReAmper (Rossi) within 90 minutes or so-a great sound-tool too!

Have fun,

Udo.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 20, 2011, 06:18:15 PM
Michael,

As I said in my building description:

The metal case/housing for the DI-box electronics, shall only be grounded on the XLR output connector pin 1, and also connected to a solder tag fixed in one of the XLR fasten screws.
(this is the only ground connection to the metal case)


It is the solder tag/lug sitting on one of the two mounting screws for the XLR connector that shall be the only box grounding point  for both the XLR pin 1 and the cable that goes to pc-card "chassis conecting point"

I dont talk about the extra ground lug on the XLR connector, but you can also use this together with the other external solder tag/lug if you want.

About that you accidentally short pin 1 to pin 3.
There is no chance that you have damaged or destroyed electronics in the DI-box, so you need not worry.

--Bo

Title: Re: Bo Hansen DI layout
Post by: Rellister on March 24, 2011, 12:41:59 PM
Hi Bo & Everybody,

Excellent project, I need some DIs so I will give it a try!
Wowi, nice tip, saves some metalwork too ;)
Ordered from Thomann, even cheap including freight to Norway!

Silent:Arts, how did you make that finish? Looks really good, sort of marble-ish (if thats a word..?)

Cheers everyone
Rune

Title: Re: Bo Hansen DI layout
Post by: Slaten on May 04, 2011, 02:14:11 PM
 Hey guys. I just have a quick question about the OEM Tranny. I have an extra one still in the box. I want to build a passive DI so I can use it backwards to try some reamping with it. The input impedance is 6k and output is 150 ohms. Thats only 40:1, but recommended numbers 500:1 with an input impedance of 50k and 100 ohm output. What do you guys think? Would the OEM tranny be fine?

Jon S
Title: Re: Bo Hansen DI layout
Post by: Slaten on May 04, 2011, 03:39:49 PM
 Hey guys. I just have a quick question about the OEM Tranny. I have an extra one still in the box. I want to build a passive DI so I can use it backwards to try some reamping with it. The input impedance is 6k and output is 150 ohms. Thats only 40:1, but recommended numbers 500:1 with an input impedance of 50k and 100 ohm output. What do you guys think? Would the OEM tranny be fine?

Jon S
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on May 11, 2011, 12:57:45 PM
Hi Slaten,

You have probably miscalculated the turns ratio.

You say OEM transforms but you might mean the OEPA262A3E, which is available as an alternative to my DI box.
This OEP has a ratio of 1:6,45 / 150 ohms to 6.25 Kohm, with parallel primary and secondary used in my DI box.

Possibly can it fit as passive DI box if you have the secondary connected in series, then you get the input impedance around 25 Kohm, but this load down a passive guitar a lot, but can work well on a synthziser or similar.

A transformer suitable for passive DI box usually have a ratio around 1:10 and 1:20, (used backwards) this was a common ratio for the microphone transformers used to for old tube gears.

--Bo
Title: Re: Bo Hansen DI layout
Post by: useme2305 on May 14, 2011, 07:46:33 AM
here's mine.
thanks to silent:arts for the quick supply of the pcb, haufe tranny.
i originally wanted to use a cheap thomann DI as a housing as suggested by volker but i ended up with the B-sized casing...i just love these boxes for their size and feel.

EDIT: i just read the entire thread and i'll definitely change the jacks to isolated ones for use with an amp and effects.
Bo is awesome. thanks so much for this extremely good sounding D.I..i'll built two more of these workhorses.

(https://lh4.googleusercontent.com/_qskvcddjepA/Tc5p8FWlfXI/AAAAAAAABMY/qo3UllWJ1OY/s800/IMG_0327.JPG)
(https://lh5.googleusercontent.com/_qskvcddjepA/Tc5p8pWcN5I/AAAAAAAABMc/eP-V3lvGSyM/s640/IMG_0328.jpg)
(https://lh3.googleusercontent.com/_qskvcddjepA/Tc5p9mvK4hI/AAAAAAAABMg/mX3EIGoaMzE/s640/IMG_0330.jpg)
(https://lh3.googleusercontent.com/_qskvcddjepA/Tc5p-AIsrUI/AAAAAAAABMk/ai8fXOXD5CQ/s800/IMG_0331.JPG)
Title: Re: Bo Hansen DI layout
Post by: MatthisD on May 16, 2011, 11:29:04 PM
I built a cheapskate version using the same enclosure, I used it for a reamp too a while ago. I didn't use OEPA262A3E transformer, I took a chance on this one Z21808E (1:6), because I was curious about it. Not much information but there is a datasheet:
http://docs-europe.electrocomponents.com/webdocs/0d72/0900766b80d72828.pdf which seems to suggest better(different at least), frequency response than the A262A3E. From what I can tell its; 150 primary/5k secondary but I'm not sure exactly.
I had to use 2x 47ohm 5% resistors for the 100R hopefully thats not going to make too much difference!?
I was surprised that it worked with no major hiccups. It needs roughly 30db of mic pre gain to get a good level, does that sound right?
Much thanks to Bo, the information here in the thread and at hansenaudio has been a great help.
Matt
Title: Re: Bo Hansen DI layout
Post by: Rellister on May 26, 2011, 04:58:59 PM
Hi Bo & Everybody,
Finished 2xDIs with Lundahls today, they work and sound excellent.
Tested with my old Precision, sounds very good.
Clean with lots of low end. Again, thanks for a cool project!

Rune
Title: Re: Bo Hansen DI layout
Post by: zebra50 on May 28, 2011, 01:59:38 PM
I thought I'd share these pics. Some friends of mine have a lot of acoustic instruments, and they wanted some DI boxes with a mute switch built in, so they could switch instruments or tune up on stage.

I built a pair of these little stomp-DI's for them, based on Bo's design. The DI and amp outs are muted by the footswitch, and there is an additional 'through' output for the tuner that is always on.

To minimise switch popping at the output, I needed to add a 1 meg pull down resistor at the switch. Also, if you use the LED on the board as the indicator lamp and switch it, then that will cause popping too, so you have to watch that!  ;)

(http://1.bp.blogspot.com/-1M-v_Ngxhdk/TeE0608fTUI/AAAAAAAAATg/uGxZcK7toSQ/s1600/BoDI1.jpg)

(http://1.bp.blogspot.com/-j7LZKQQ3cG4/TeE07UJbTmI/AAAAAAAAATk/IYY-jn8EM8k/s1600/BoDI3.jpg)

(http://3.bp.blogspot.com/-LGJ1gKtsge4/TeE08KSUg_I/AAAAAAAAATo/EV9DbvnmlZE/s1600/BoDI2.jpg)

Anyway, they sound good, are very useful. I like them so much that I'm going to make a couple for myself. Thanks again to everyone who contributed to this.

Stewart
Title: Re: Bo Hansen DI layout
Post by: flaheu on May 30, 2011, 06:22:50 AM
Zebra,

I'm interested in your version, where did you put the "tuner out", have you "doubled" the amp out and put the mute after the other one to stop feeding the eventual amp ?

Thanks
Title: Re: Bo Hansen DI layout
Post by: zebra50 on May 30, 2011, 06:50:20 AM
Hi!

For the tuner output I just paralleled the input - very simple.

Stewart

Title: Re: Bo Hansen DI layout
Post by: ChrisPbass on May 30, 2011, 12:00:56 PM
Nice work Stewart. Are those cases readily available, can't say I've seen any like that for sale anywhere?
Chris
Title: Re: Bo Hansen DI layout
Post by: zebra50 on May 30, 2011, 01:31:03 PM
Hi Chris,

The cases are really cool and are reasonably priced, even with postage from the US. They are nice quality cast aluminium and were really easy to machine, even on my feeble drill press!
I found them on Ebay - I searched for stompbox enclosure or something similar. Here you go...

http://shop.ebay.co.uk/pedalenclosures/m.html?_trksid=p4340.l2562

They had unfinished ones when I looked for a couple of bucks less, but those painted ones look really nice too.

Title: Re: Bo Hansen DI layout
Post by: ChrisPbass on May 30, 2011, 01:48:58 PM
Hi Chris,

The cases are really cool and are reasonably priced, even with postage from the US. They are nice quality cast aluminium and were really easy to machine, even on my feeble drill press!
I found them on Ebay - I searched for stompbox enclosure or something similar. Here you go...

http://shop.ebay.co.uk/pedalenclosures/m.html?_trksid=p4340.l2562

They had unfinished ones when I looked for a couple of bucks less, but those painted ones look really nice too.



Cheers Stewart, just the job with a nice retro vibe about them. May have to invest :)
C
Title: Re: Bo Hansen DI layout
Post by: flaheu on May 31, 2011, 09:47:31 AM
Thanks Zebra50,

It's obvious whan you look at the wiring !
I'm getting old, I should wear glasses  ::)

Thanks
Title: Re: Bo Hansen DI layout
Post by: Holger on June 20, 2011, 10:14:03 AM
Just to share, and already posted in Frank's German forum: I managed somehow to put two channels in the little modushop case.

(http://audiofor.tv/diy/dualdi/front.jpg)

(http://audiofor.tv/diy/dualdi/oben.jpg)

(http://audiofor.tv/diy/dualdi/schicht.jpg)
Title: Re: Bo Hansen DI layout
Post by: lorcan on July 05, 2011, 02:02:30 PM
Hi all,

here is my build with an audiomaintenance 9045 transfo (http://www.audiomaintenance.com/acatalog/CA-18-VTB9045_extended_info.html)
(http://)

I did my own layout using Eagle cad to fit this in a Hammond 1590B die-cast box, which is often used for guitar FX pedals.
It looks very sturdy, and it's quite a tight fit, but it works and sounds great
Thanks for this great project, Bo  8)
Title: Re: Bo Hansen DI layout
Post by: lorcan on July 05, 2011, 02:03:41 PM
Gutshots ...
Title: Re: Bo Hansen DI layout
Post by: lorcan on July 05, 2011, 02:16:03 PM
And finally the pcb (pdf), layout & components (http://www.lorcan.me/wordpress/wp-content/uploads/2011/07/Bo-Hansen-DI-LMD-for-9045.zip)
Title: Re: Bo Hansen DI layout
Post by: culteousness1 on July 11, 2011, 07:12:01 AM
Hi all,

just finished my Oxford Edition:

(http://culteousness.square7.ch/DIY/PICS/hansen_di1.jpg)
(http://culteousness.square7.ch/DIY/PICS/hansen_di2.jpg)

Working from first fire-up and really nice sounding.

Thanks to Bo, Soeren, Luny Tune, Gustav and Frank!

Cheers,
Carsten
Title: Re: Bo Hansen DI layout
Post by: kante1603 on July 11, 2011, 04:05:37 PM
O.k, here are mine (the upper ones are duals-holger "triggered" me doing that ;D)
Cases are modushop from italy,panels from NRG (thx Frank!),all with Haufe transformers.
(http://img823.imageshack.us/img823/9334/ditower4.jpg)
They have nice black screws on the front in the final version.

Best,

Udo. ;)
Title: Re: Bo Hansen DI layout
Post by: Edward on August 17, 2011, 07:15:06 AM
Hi!


I just ordered my first Carnhill transformers, modell VTB9045, and im going to try and build a Bo Hansen Di box using these. I have recently finished a 2ch version with Lundahl LL1538XL transformers and that turned out great! Im really happy with the result. Thank you Bo, and Gustav for the PCB. Thanks also to all who posted here for great tips and tricks and inspiration.

My question is how to connect the pins on the Carnhill VTB9045 transformer to the tranformer "holes" on the PCB? Im a little unsure and a little too incompetent myself to make up my mind.

I have read that others have succseeded with the same project and if anyone would like to share their experience i would be very thankfull.


Kind regards,


Edward.


Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 17, 2011, 11:57:12 AM
Edward,

To match my DI-box you shall do this pin configuration on the Carnhhill VTB-9045

link pin 8+9 (not connected to pc-card)
pin 7 connect to pc-card point 6
link pin 6+10 and connect to pc-card point 8

link pin 2+3 and connect to pc-card point 1
link pin 4+5 and connect to pc-card point 2

NOTE about transformer case grounding
Use a solder-lug with a screw to one of the transformer fixing holes, and link also this to pin 6+10
Do not screw the transformer case direct to the DI-box metal box/case, it must be isoleted from the metal box.

--Bo
Title: Re: Bo Hansen DI layout
Post by: blue_lu on September 06, 2011, 06:12:16 PM
finally finished my di box. will put it through its paces soon with rhodes and synths...
build is not very clean, but I am beginner with almost no tools - so I had to drill the box by hand and so on. came out alright I think!
(http://img713.imageshack.us/img713/9803/20110906200902.th.jpg) (http://img713.imageshack.us/i/20110906200902.jpg/)
twp channels
(http://img855.imageshack.us/img855/6016/20110906202024.th.jpg) (http://img855.imageshack.us/i/20110906202024.jpg/)
close up
(http://img690.imageshack.us/img690/3638/20110906202437.th.jpg) (http://img690.imageshack.us/i/20110906202437.jpg/)
working!
(http://img690.imageshack.us/img690/5271/20110906204029.th.jpg) (http://img690.imageshack.us/i/20110906204029.jpg/)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 15, 2011, 12:41:55 PM
Matt,

The transformer you use have a bit more loss compare with Lundahl LL1538, so it is ok that you must use a bit more gain.

Two 47 ohms resistors connected in series, is near same as a 100 ohm resistor, so this is also ok.

--Bo
Title: Re: Bo Hansen DI layout
Post by: funkymonksf on September 15, 2011, 02:24:09 PM
If possible could someone guide me in how I could add a volume control and a simple tone control to this circuit. I need to be able to adjust these factors on stage. It's for an acoustic guitar that has no on-board controls. Any advice or ideas are much appreciated.

-Brice
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 15, 2011, 03:03:43 PM
Brice,

It is difficult to direct implant your wishes with volume and tone control on this circuit since it only consists of a two stage emitter folower with no gain.

Your wishes need a completely different circuit design to work well.

If you want to use a balanced phantom powered microphone input as receiver for your intended acoustic guitar pre amp, you can use the original DI-box design as a output amp, and then add a front end amplifier with gain control, bass and treble control .

This add-on amplifier may consist of two transistors which is also fed by the phantom power systems that are already on the original DI-box PC-Card.

Tell me a little bit more what kind of guitar pickups you intend to use, and what kind of an equalizer you want, and what you plan to connect the pre amp to.

Maybe if I get time, I can design something simple and clever to you and others who may be interested in something similar.

--Bo
Title: Re: Bo Hansen DI layout
Post by: funkymonksf on September 15, 2011, 04:38:05 PM
That'd be wonderful. As far as the pickups being used its the K&K Pure Mini (link)  http://www.kksound.com/puremini.html . Its a passive transducer pickup. Sounds wonderful might I add, but I need to be able to control the volume and would like to have simple control over the hi and lo frequencies as I find it more than beneficial in a live setting.

 So Ideally I am thinking that a direct input box that took your active circuit, which i am adamant to use based on such wonderful feedback, and having a front end that had volume control and both hi and lo controls. I dont think mid will be necessary, nice, but not needed.

Is there any reading or schematics that I could refer to for inspiration?

I am hoping to build this within a months time as it is needed for a small tour coming up.

Thanks for such a quick response. I hope something can be built out of this dialogue.

-Brice
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 17, 2011, 10:14:52 AM
Brice,

I have received numerous inquiries on various modifications on my DI box in the most varied designs.

I have an idea that in the future to do a DIY thread to be called "have fun with the 1975 DI-box PC-card" and where I will try to make a lot of clever designs with this PC card and a small ad-on PC-card.
But of course, it's all about time, and I'm mostly busy with running my business, so it be when I get some free time.

When it comes to your desires, do you need more gain compare when you plug the acoustic guitar right into the original DI-box ?
What type of equalizer, a one knob treble or bass cut, or a one-knob tone balance/tilt, or two knobs normal treble & bass?

--Bo
Title: Re: Bo Hansen DI layout
Post by: funkymonksf on September 17, 2011, 02:00:08 PM
Bo,

Thanks for your time! Truly. I think a one knob gain control with the ability to boost and cut would be best. And for eq I think a two knob setup would be best with simple treble and bass control.

I'm excited to learn through this project, have you any suggestions for reading and schematics to learn from.?

Thanks again,
Brice
Title: Re: Bo Hansen DI layout
Post by: funkymonksf on September 21, 2011, 08:07:38 PM
I've been searching rather hard to come to a simple understanding of what circuit one would need to control and boost an acoustic guitar. I see plenty commercial products, but obviously their schematics are private and of no help. Does anyone know where I could start searching or simply a discrete circuit that'd rock this acoustic guitar ambition?

I appreciate any comments, especially productive ones

Brice
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 22, 2011, 02:00:17 PM
Brice,

Googling on  guitar pre amp + schematic   and you'll find lots of construction examples.

--Bo
Title: Re: Bo Hansen DI layout
Post by: gzpz on September 23, 2011, 06:53:25 PM
I just finished four DI's...  I got half way through before I came up with the idea of putting some Swedish colors on them!  They work great  but I didn't realize that I should only use red LED's...  How big a difference does this make?  I was thinking of putting a bypass switch on the LED's just to get a comparison between "with" and "without" the LED indicator. 

I find a subtle difference between them sonically, with the red and blue one sounding best to my ear.  Must be small differences in component values(?).  I just coupled these with an AML EZ1073 500 series kit preamp and got a GREAT sound tweaking the EQ on the mic pre...

Thanks!  Great, easy, and fun to build!


Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 23, 2011, 09:21:59 PM
Hi "gzpz"

Nice color on your boxes, as a Swede I feel honored.

Because the LED's are connected in series with internal 24 volt feed to the DI-box electronics, it is good that the LED have so small voltage drop as possible.

Red LEDs have the smallest voltage drop compared to other LED colors.

Of course a few volts loss gives little difference for the DI-box headroom, but if we designers get to choose, we would rather choose some dB more headroom than a blue LED.

--Bo
Title: Re: Bo Hansen DI layout
Post by: gzpz on September 23, 2011, 10:39:12 PM
I might try a different LED to tell if I hear a difference...

Yes, I'm from the USA, but my mother was Swedish and my godfather still lives in Gothenburg, now in his 80's, he was an electrical engineer, and is a wonderful guy.  I didn't have a good way to label the boxes but wanted to give you some honor for such a nice clean design!
Thanks again-
Dan
Title: Re: Bo Hansen DI layout
Post by: useme2305 on October 04, 2011, 04:10:49 AM
built two more of these awesome sounding boxes.
Title: Re: Bo Hansen DI layout
Post by: useme2305 on October 04, 2011, 04:13:41 AM
as you can see i had to do some routing to the board to make it work like that.

i just like my xlrs on the top to be able to plug and unplug my cabling with one hand by stomping on the box.
Title: Re: Bo Hansen DI layout
Post by: CJ on October 04, 2011, 04:29:11 AM
full props to bo hansen

who else is gonna show up?

frickin jeezus?

wth, over

king of direct, so give some respect  :D

should i see pat travers oct 7 at the el ray ,


or not?

can that old canadian still get it?

Title: Re: Bo Hansen DI layout
Post by: chrispsound on October 04, 2011, 02:33:18 PM
full props to bo hansen

who else is gonna show up?

frickin jeezus?

wth, over

king of direct, so give some respect  :D

should i see pat travers oct 7 at the el ray ,


or not?

can that old canadian still get it?


CJ, You mean the Fox Theatre in Redwood City,  If you show up on the 7th at the El Ray I think you will be dissapointed. ;)
Title: Re: Bo Hansen DI layout
Post by: PeteC on October 09, 2011, 11:52:31 AM
Just finished my Bo H DI today -  and been playing Waves GTR 3 with it as a front end to my interface - great box !!

sounds really nice on Bass guitar too.

Thanks Bo - I know this is an old project now, but you have another very satisfied DIY'er here

great addition to my little project studio.

Cheers
PeteC
Title: Re: Bo Hansen DI layout
Post by: Edward on November 14, 2011, 03:18:03 PM
Hi!


I built four of these DI boxes with various transformers and i am really happy with all of them.


I am thinking about adding a variable hipass filter to my boxes, maby 20 - 400Hz. After a few nights of studying i am still unsure how to add this to the DI box...


Does anyone have experience with this or ideas on how to go about?



Kind regards,


E.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on November 14, 2011, 03:55:35 PM
Edward,

There are two places in the circuit where you easy can make 6 dB per octave bass roll-off filter.

It is to reduce the 0.1 uF capacitor at the input, or reducing the 10 uF electrolytic on the output before the transformer.

With a switch may be choosing between a number of different values ​​of the capacitor.

As an example, the output capacitor can end up on the values 10 uF, 4.7 uF, 1 uF, 0.47 uF, but the best is to test out the value according to your own taste.
The bass roll-off may change slightly depending on the load Di-box is connected to, this is due to mirror impedance of the transformer.

If you do it with the input capacitor, will probably bass roll-off to become more constant, but the capacitor's value will be very small, due to the high input impedance of 1 Mohm.

There is another trick to get 12 dB per octave roll-off, adding another capacitor in series with the input capacitor, and between these connect a resistor that goes to the output on the last transistor.
Both of these capacitors must be changed in value for different roll-off frequencies

However, this circuit can probably affect the input impedance of the DI-box compared to the original design.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Edward on November 15, 2011, 02:09:03 PM
I will start testing this by reducing the electrolytic capacitor on the output and see how it works out!

Thank you again Bo for helping out!



Kind regards,


Edward.
Title: Re: Bo Hansen DI layout
Post by: Edward on November 22, 2011, 04:25:23 PM
Hi again

I soldered a rotary switch with 5 positions choosing between 10uF, 4,6uF, 1uF, 0,33uF and 0,1uF as a first test. Then i fed pink noise into the DI box and had a spectrum analyzer to see what happens on the output. With the rotary switch at 10uF i had a completly flat response. Turning the rotary switch all the way to 0,1uF gave me a HPF somewhere around 60-70Hz acording to my analyzer.
I tried this with an electric guitar as well, and i thought the HPF was only and barely audible at its max position at 0,1uF. There was also a small pop when changing between the different settings on the rotary switch.

Now i am wondering what kind of capasitor i could use if i want to go smaller than 0,1uF to get my HPF to say 300-400Hz, and of course not affect the sound of the DI box?

Ideas?


/Edward
Title: Re: Bo Hansen DI layout
Post by: Apache5 on November 27, 2011, 07:59:39 AM
Hi everybody! let me show you my 1U rack 8 Bo's DI version  :)  they have an intrnal psu. Its for a band of a friend and they want a ground lift and a pad... I know that the groun lift is not required in that design but is easier and they are more relaxed with it  than try to explain to tem why its not necessary..  :P   I  put in them the haufe transformer.
Thanks Bo Hansen for that very nice ciruit and all who have made this design possible!!

Sorry for the big pics...

(http://img.photobucket.com/albums/v322/Apache5/Gear/Che%20Sudaka%20DI/BOHansen8DIinside.jpg)

(http://img.photobucket.com/albums/v322/Apache5/Gear/Che%20Sudaka%20DI/BoHansen8DIfront.jpg)

(http://img.photobucket.com/albums/v322/Apache5/Gear/Che%20Sudaka%20DI/BoHansen8DIback.jpg)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on November 27, 2011, 05:51:47 PM
Edward,

Simply change the capacitor that drive the output transformer primary, may be a rather uncontrolled and smooth slope.

With just a capacitor in series (passively coupled) becomes only a slope of 6 dB / octave, and if you have varying load from time to time on the DI-box XLR output, this will make the bass cut filter does not become constant.

Let me come back with a smarter solution to this problem, so I can save a lot of experimentation for you.

Maybe I have a some spare time between Christmas and New Year to take a look at this.

--Bo
Title: Re: Bo Hansen DI layout
Post by: lordnielson on January 04, 2012, 08:01:54 AM
Just built a couple of these and they are awesome. Thanks to those who made it possible.

A quick question: Does the "amp out" pass through the transformer. Logically I don't see why it would but I'm pretty certain that I hear a "thickening" of the tone. Placebo ?

Thanks
Peter
Title: Re: Bo Hansen DI layout
Post by: pedrocruz on January 25, 2012, 01:56:21 PM
Hello Guys,
I need some advice from you guys, i want to make 8x DIs for electronic music, so, as im not aware of the Xformer diferences, what do you guys would recommend for electronic music. I would like to have the most possible beat definition and punch, and great transient response would be important.
I dont even know if i'll ear a diference between jensen vs lundahl vs sowter vs whatever, but maybe you guys can share your experience with xformers.

Also, i want to make a passive summing of the lines that are feeding the 8x DIs, so i would have 4 stereo feeds to the FOH PA system, and a stereo summ of the 8 channels into monitor mixer, to make things easier in Festivals etc.
Can i make a parallel on the DI inputs and then make a passive summ onto Left XLR and Right XLR? here i wont need to drive the summ into mic pres because i would run the signal into the monitor mixer where it will be amplified.
Any advice for this?

Thank you guys in advance!
 
Pedro Cruz
Title: Re: Bo Hansen DI layout
Post by: loicm on January 26, 2012, 02:10:18 PM
Hello,

I'm building some Bo Hansen DI. I measured  a few transistor and found HFE to be around 250 to 520 for the BC550 and 341 to 363 for the BC560.

What HFE do you recommend ? What could append if I use one with 520 and the other with 363 ?  Is it class A design ? It looks like a darlington stage with two transistor. I am right ?  If it is not AB class, is there a risk to use different HFE ?

Best regards,
Loïc
Title: Re: Bo Hansen DI layout
Post by: Nele on January 26, 2012, 02:33:01 PM
I'm building two of these for a studio which doesn't have phantom power (disabled it on the desk, they use tube mics with their own psu.. ;) ).
Is it possible to run these on external 24V power? And if so, should I connect it to where it says +24V on the schematic?

Thanks!
Corneel
Title: Re: Bo Hansen DI layout
Post by: dmp on January 26, 2012, 02:41:36 PM
I would think so  - probably would want to omit the two 6.8k going to the XLR out to prevent voltage going to the input of your preamp.
Title: Re: Bo Hansen DI layout
Post by: Classicaudio77 on January 26, 2012, 04:56:21 PM
I have reviewed the posts and have seen the questions and answers regarding connector wiring, but am still a bit confused. Maybe I just need more coffee.

I will start with the XLR's. I purchased Neutrik DLX series connectors which feature a "duplex ground contact". I can not find documentation on what that actually means, but it says "New duplex ground contact for excellent contact integrity between chassis and cable connector".

I understand XLR 1, 2, 3, on the PCB obviously go to pins 1,2,3 on the connector. If I understand correctly, the ground tab on the connector (next to pin 1) gets soldered to pin 1.

Where I am confused is the Chasis pad on the PCB. In some of the project pictures, it looks like it is not being used at all (unless wire is soldered on the bottom). In the ones that are using it, I can't tell where it is connected on the other end.
Does it also get soldered to pin 1 on the connector, or does it go to one of the actual mounting screws that hold the connector to the chassis?
Title: Re: Bo Hansen DI layout
Post by: Nele on January 26, 2012, 05:02:04 PM
Where I am confused is the Chasis pad on the PCB. In some of the project pictures, it looks like it is not being used at all (unless wire is soldered on the bottom). In the ones that are using it, I can't tell where it is connected on the other end.
Does it also get soldered to pin 1 on the connector, or does it go to one of the actual mounting screws that hold the connector to the chassis?
Here's what I would do (as per Bo's instructions on his site, see page 1):

1. Connect XLR pins to board with wires
2. Solder extra wire to pin one of xlr with an eyelet at the end
3. Solder a wire to the chassis-pad with an eyelet at the end
4. Connect both eyelets to one of the fixing screws of the XLR

note: no connection from XLR pin 1 to tab on XLR

Title: Re: Bo Hansen DI layout
Post by: Classicaudio77 on January 26, 2012, 06:17:15 PM
Quote
Here's what I would do (as per Bo's instructions on his site, see page 1):

1. Connect XLR pins to board with wires
2. Solder extra wire to pin one of xlr with an eyelet at the end
3. Solder a wire to the chassis-pad with an eyelet at the end
4. Connect both eyelets to one of the fixing screws of the XLR

note: no connection from XLR pin 1 to tab on XLR

Okay, so two wires to the chassis/xlr screw, one from pin one of XLR, one from the PCB Chassis pad, ground tab on xlr does not get used! Thanks.

I have mounted my XLR's from the inside (I like the cleaner look). I know that usually the ground lugs should have good contact with the chassis. Any sugestions on this?


Title: Re: Bo Hansen DI layout
Post by: Nele on January 26, 2012, 06:23:26 PM
I have mounted my XLR's from the inside (I like the cleaner look). I know that usually the ground lugs should have good contact with the chassis. Any sugestions on this?

The XLR should be conducting and if the inside of the chassis isn't painted, the ground connection from chassis to solder-eyelets-on-screw should be fine. If in doubt you can always sand the inside of the chassis around the hole for the screws so the XLR makes a good ground-contact. You could also use two anti-shake washes between XLR and chassis for better contact.
Title: Re: Bo Hansen DI layout
Post by: rooster21 on February 29, 2012, 09:42:07 PM
Hey,

Just though I would post a pic of my finished units. Black model is with Lundahl, silver is with Haufe. Thanks for the awesome design.
Title: Re: Bo Hansen DI layout
Post by: Hank Dussen on March 01, 2012, 02:40:06 AM
cool!
With the schematic on top!
Title: Re: Bo Hansen DI layout
Post by: bpucekov on March 01, 2012, 03:34:01 AM
this is super ultra coooool
Title: Re: Bo Hansen DI layout
Post by: lars78 on March 01, 2012, 06:35:55 AM
would show my units...
(http://starfishcoffee.de/di3.jpg)
(http://starfishcoffee.de/di4.jpg)
(http://starfishcoffee.de/di5.jpg)

the black ones are with Haufe, the silver ones with Neumann BV107
Title: Re: Bo Hansen DI layout
Post by: Classicaudio77 on March 04, 2012, 06:45:06 PM
I notice you did not use the the chassis ground and/or ground from pin 1 of the XLR's. Any grounding issues with your units?
Title: Re: Bo Hansen DI layout
Post by: lars78 on March 04, 2012, 07:36:06 PM
i connect the XLR chassie connector to XLR pin 1. That is difficult in the picture to see. 
btw. this design works perfect in the studio and on stage, also sound excellent ! yesterday i used 3 pcs on Bass, acoustic git and cello PU.


 
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 06, 2012, 12:52:05 PM
Sorry guys, I have not been on the forum the last time, I've had too much to do at my company, But will now try to answer your questions.

First of all, please always read my DI-box DIY instructions available here: www.hansenaudio.se/techpage.htm
There is lots of build information,  circuit explanation, different choices of transformers, transistors and other components and much more, that can provide answers to your questions and problems.


Loicm
In this simple dual emitter follower circuit, is not Hfe so important, but to secure the high impedance and working point/bias on the first transistor base, it is good to have a transistor with at least medium Hfe.
But avoid using the "A" graded transitors due to some unknown brand that may have poor Specifications.
Use BC550/BC560 B or C, in better brands as Philips, Motorola, Fairchild, National, SGS/Ates.

Nele
You can apply regulated +24 volt on the positive side of 100 uF electrolytic capacitor.
But take away the two 6.8 k resistors.
Note that the ground/- 24 volts must be connected to pin 1 on the XLR connector, so the ground loop suppression circuit work correctly.

Classicaudio77
The extra connection/ground-lug you can find on a Neutrik or other XLR connectors is designed to properly ground the housing/frame on the connectors.
This additional ground-lug is used such as a chassis connectors shall be mounted in a box or panel made ​​of plastic or wood. where the box or panel is not automatically connect the connectors housing/frame to ground.
If you wish, you can connect this additional ground-lug to XLR pin 1, it will be a further ground to the DI-box case, the same way as in the original, so it does not matter.
Can be an extra precaution if there is painting and anodizing to insulate between the connector and box/case.

As I describe on my web page, the ground connection between the PC card, connector and DI box case, to be made ​​as follows:

XLR pin 1 shall be connected to the PC card connecting point labeled "XLR out 1" and the PC card connecting point labeled "chassis" be connected to the DI-box case on a separate screwed solder lug or a solder lug attached to one of the XLR  mounting screws.

If you are not using our specially designed PC cards, and instead build the electronics on your own way, please carefully follow the "metal box / case ground" instruction, which you can find on my web page.

Lars78
Sure, it is also possible to use the extra XLR ground-lug connected to XLR pin 1 without PC card connecting point "chassis" is connected, but then you have to trust that the painting/anodizing on the XLR housing and DI box case does not make any insulation.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Nele on March 06, 2012, 06:01:20 PM
Nele
You can apply regulated +24 volt on the positive side of 100 uF electrolytic capacitor.
But take away the two 6.8 k resistors.
Note that the ground/- 24 volts must be connected to pin 1 on the XLR connector, so the ground loop suppression circuit work correctly.

Thanks for the reply! I also had to connect the red LED differently because if I connected it as it is on the pcb it kept blowing up.

Cheers and thanks for your design!


 
Title: Re: Bo Hansen DI layout
Post by: lars78 on March 06, 2012, 08:18:13 PM
@Bo
i know the "painting problem", and i measured from Pin 1 to the chassis... no problem (-:

what do you think about the neumann BV-107 transformer in your design ? it´s from the neumann KM84.
it´s approximately 3db less gain at the output with the BV107 than with the Haufe
(http://starfishcoffee.de/bv107.jpg)
 
Lars
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 08, 2012, 02:09:36 PM
Lars78,

Neumann "09107" is a good transformer, maybe a bit small for high level in the low end.
As you say, it have a bit more loss compare with Lundahl and Haufe, but approx. same loss as OEP.

--Bo
Title: Re: Bo Hansen DI layout
Post by: lars78 on March 11, 2012, 08:05:20 PM
I mostly use it for acoustic guitar, rhodes, bass guitar or other instruments with PU.
I think that should work well...

Lars
Title: Re: Bo Hansen DI layout
Post by: Classicaudio77 on March 15, 2012, 01:23:32 PM
Thank you for your input Bo.
I have a couple of these built with the OEP and they sound great.

I have a couple of questions on component selection.

1) I have access to some high quality Mil Spec resistors (0.1% 25ppm), but they are 1/8 watt instead of 1/4 watt. Will these be okay in this circuit, or must they be 1/4 watt and above?

2) Will the quality of the electrolytics make a difference in sound quality in this circuit? I built mine with Panasonic FC series, but was wondering if using some of the speacialty "audio" caps like Nichicon Muse (KZ) or Elna Silmic will make any difference.
Also, any audible difference between Polyester and Polypropolene for the .01uF's?
I know there are often debates on whether or not capacitors can make an audible difference. These DI's sound great as they are, just wondering if anyone has experimented with the caps.

3) I understand using an LED other than red will have a higher voltage drop. What does a higher voltage drop do in terms of the circuit? Will it affect audio quality, output etc..?

4) I did a search from the place I bought my OEP transformers from (Newark Electronics) and I notice that now another transformer comes up when I search the OEP part number. Looks exactly the same as the OEP but manufacturer is VIGORTRONIX. Anyone ever hear of them?
Title: Re: Bo Hansen DI layout
Post by: tronnyjenkins on March 18, 2012, 02:32:03 PM
Re-post from The Lab-


I finished my first of two Bo Hansen 1975 DIs yesterday. The metal work was the worst part, haha.
Anyway, I had a question regarding noise. When I plug in my telecaster through pro tools and the eleven plug in, there is a lot of noise if I take my fingers off of the strings. Is this normal for a tele or did I mess something up ground wise?
I did notice that on Bo's website he mentions using plastic 1/4" jacks, whereas I used metal...
Title: Re: Bo Hansen DI layout
Post by: useme2305 on March 18, 2012, 03:08:26 PM
the plastic insulated connections are a must for this design.
Title: Re: Bo Hansen DI layout
Post by: tronnyjenkins on March 19, 2012, 05:19:49 PM
OK, so I replaced the metal TS connectors for plastic ones, and also built my second DI box. This time I tried it with my Mustang bass, and they are both still making noise. I was trying to figure out what the issue could be, and while doing so grabbed the xlr cable where it connects to the box. The noise goes away.

So- me grabbing the XLR connector or keeping my hands on the strings, no noise. Same for two DI boxes. Is it possible I have a ground issue with my preamp?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 20, 2012, 06:41:08 AM
tronnyjenkins,

If you use the pc-card and you have followed my build instructions thoroughly, and done all the steps so that the grounding, metal case and connectors will work properly.
Then it should not be any interference problems that come from the DI-box.

Probably there is something in your environment, housing, studio that produces the noise/disturbance, since you say that your guitar picking up interference, and that it is better when you grab the guitar strings.

The noise can come from your sound-card, computer or computer monitor.
Try DI-box on any other equipment, as an analog studio or PA mixing console.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Classicaudio77 on March 27, 2012, 02:51:21 PM
Would one of these Edcor Transformers be a good fit in this DI?

http://www.edcorusa.com/p/110/mxl5cs (http://www.edcorusa.com/p/110/mxl5cs)

http://www.edcorusa.com/p/102/mx5 (http://www.edcorusa.com/p/102/mx5)

http://www.edcorusa.com/p/132/pcw600-15k (http://www.edcorusa.com/p/132/pcw600-15k)

http://www.edcorusa.com/p/145/wsm600-15k (http://www.edcorusa.com/p/145/wsm600-15k)


Title: Re: Bo Hansen DI layout
Post by: lars78 on March 29, 2012, 10:03:09 PM
Hello Bo,

these are the correct versions of SA970 (http://www.reichelt.de/2SA-Transistoren/SA-970/index.html?;ACTION=3;LA=5;GROUP=A171;GROUPID=2898;ARTICLE=15744;START=0;SORT=user;OFFSET=500;SID=12T1wAHH8AAAIAAGtyRrAd60014cd2ea4ca90b2f4ba1d9d1cba8f) & 2SC2240 (http://www.reichelt.de/2SC-Transistoren/SC-2240/index.html?;ACTION=3;LA=5;GROUP=A173;GROUPID=2900;ARTICLE=16435;START=0;SORT=user;OFFSET=500;SID=12T1wAHH8AAAIAAGtyRrAd60014cd2ea4ca90b2f4ba1d9d1cba8f) ?

data sheet (http://www.reichelt.de/index.html?;ACTION=7;LA=3;OPEN=0;INDEX=0;FILENAME=A100%252F2SA970-2SC2240_CDIL.pdf;SID=12T1wAHH8AAAIAAGtyRrAd60014cd2ea4ca90b2f4ba1d9d1cba8f)

best

Lars
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 30, 2012, 07:40:19 AM
Classicaudio77,
Compare with Lundahl, Haufe and OEP versions have this MX5 poor headrom in the low end, and some other strange behavior.
We have talk about this earlier in this topic.

Lars78,
Yes, this is very nice low noise high voltage audio transistor, but a bit overkill for this application.
Watch up for different pin-out.

--Bo
Title: Re: Bo Hansen DI layout
Post by: lars78 on March 30, 2012, 11:15:47 AM
...yes, but the difference is only 0,07 € to the BC550.  :)

 
Title: Re: Bo Hansen DI layout
Post by: volker on March 30, 2012, 07:38:59 PM
The 2SA970 from Reichelt is the GR version, so hFE is only between 200-400 as per datasheet. Same probably goes for the 2SC2240, but I never bought it there.
Title: Re: Bo Hansen DI layout
Post by: tronnyjenkins on March 30, 2012, 10:04:24 PM
tronnyjenkins,

If you use the pc-card and you have followed my build instructions thoroughly, and done all the steps so that the grounding, metal case and connectors will work properly.
Then it should not be any interference problems that come from the DI-box.

Probably there is something in your environment, housing, studio that produces the noise/disturbance, since you say that your guitar picking up interference, and that it is better when you grab the guitar strings.

The noise can come from your sound-card, computer or computer monitor.
Try DI-box on any other equipment, as an analog studio or PA mixing console.

--Bo

Thanks Bo!
I suspected that would be the case, and I'm very happy with the tone of the DI.
Title: Re: Bo Hansen DI layout
Post by: turnthesoff on March 31, 2012, 10:03:12 AM
I really want to make this DI, but I can't see the schematic or parts list or anything because the site is "suspended" whenever I try to get on it!
Title: Re: Bo Hansen DI layout
Post by: lars78 on March 31, 2012, 08:26:32 PM
PCB´s
http://www.groupdiy.com/index.php?topic=10776.0

Partlist
EU: http://www.mentol.dk/diy/bohansen/BOM - Diyfanatic - bo DI.xlsx (made by diyfanatic)


iron
http://www.groupdiy.com/index.php?topic=39570.0

case
http://de.farnell.com/jsp/search/productdetail.jsp?sku=3824421
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 01, 2012, 07:36:44 AM
Sorry, my web site is temporarily shut down, because the server has been exposed to virus.
Together with my web-hotel, I am trying right now to solve this problem.

Hope it is cleaned and "on-air" sometime next week.
--Bo
Title: Re: Bo Hansen DI layout
Post by: ksor on April 01, 2012, 10:14:40 AM
Argh - I need schematics and details on Bo's DI box - can I get it somewhere else ?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 01, 2012, 02:23:04 PM
ksor,

You have a PM from me.

--Bo
Title: Re: Bo Hansen DI layout
Post by: ksor on April 01, 2012, 03:21:28 PM
ksor,

You have a PM from me.

--Bo

Thx - very much !
Title: Re: Bo Hansen DI layout
Post by: turnthesoff on April 02, 2012, 12:37:26 AM
Could I possibly have those schematics as well?
Title: Re: Bo Hansen DI layout
Post by: ksor on April 02, 2012, 02:17:42 AM
Could I possibly have those schematics as well?

I only got the description - I'll try to get the schematic from Bo ig I can find his mail address.
Title: Re: Bo Hansen DI layout
Post by: Sredna on April 02, 2012, 09:56:05 AM
 8)
Title: Re: Bo Hansen DI layout
Post by: ksor on April 02, 2012, 12:54:58 PM
8)
I remember reading something and seeing some PCB with a LED, but I see no LED in this schematic - is it THE LATEST version ?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 02, 2012, 01:33:55 PM
Now my web-site fixed and opened again, but it will probably take a few days before Google's warning text will disappear.

ksor,
It is the only schematic available right now, I have the original on my desk as a reminder that I will change this so that it conform to the PC layout, but have not had time yet to do so.

The difference is not very large, the modified components are described in my help text, and the LED is labeled on the PC board where to sit.

--Bo
Title: Re: Bo Hansen DI layout
Post by: ksor on April 04, 2012, 12:47:36 PM
I want to change the XLR to a stereo 6,5mm Jack - what shall be connected where ?

Title: Re: Bo Hansen DI layout
Post by: ksor on April 04, 2012, 12:49:04 PM
Is the layout of the PCB critical ?

 - I want it so small as posible and the trafo will be separate.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 04, 2012, 02:15:18 PM
ksor,

Tele plug tip the same as XLR pin 2,
ring same as XLR pin 3,
sleve as XLR pin 1

No, PC layout is not particularly critical, but it is important that you carefully follow my instructions regarding grounding.

--Bo
Title: Re: Bo Hansen DI layout
Post by: ksor on April 04, 2012, 03:31:31 PM
ksor,

Tele plug tip the same as the XLR pin 2,
ring the same as the XLR pin 3,
sleve same as XLR pin 1

No, PC layout is not particularly critical, but it is important that you carefully follow my instructions regarding grounding.

--Bo

Thx Bo !
Title: Re: Bo Hansen DI layout
Post by: Mondy on April 05, 2012, 05:37:27 AM
Quote
No, PC layout is not particularly critical, but it is important that you carefully follow my instructions regarding grounding.

Hi Bo

If you are updating the schematic, would it also be possible to maybe clarify the grounding scheme on the schematic also, or maybe provide a simple diagram instead of text, as this aspect seems to be a source of confusion for many people, me included, who are building your wonderful little DI?

Cheers
Ray
Title: Re: Bo Hansen DI layout
Post by: ksor on April 05, 2012, 07:34:06 AM
Someone please confirm that THIS is where the LED should be placed and that the LED is the ONLY component that should be added:
Title: Re: Bo Hansen DI layout
Post by: Mondy on April 05, 2012, 08:09:31 AM
Hi Ksor

The LED should be moved to in between R6 and R8 with its cathode facing R6.

Also some values have changed…
R3 & R4 should be 100K
R10 should be 100R
C3 should be 100n
C5 should be 10uF

Hope this helps & someone correct me if I'm wrong!

Cheers
Ray
Title: Re: Bo Hansen DI layout
Post by: ksor on April 05, 2012, 08:25:13 AM
Hi Ksor

The LED should be moved to in between R6 and R8 with its cathode facing R6.

Also some values have changed…
R3 & R4 should be 100K
R10 should be 100R
C3 should be 100n
C5 should be 10uF

Hope this helps & someone correct me if I'm wrong!

Cheers
Ray

????? > Mondy

Placing of the LED in this link is not like that, I think: http://www.mentol.dk/diy/bohansen/silkscreen.pdf (http://www.mentol.dk/diy/bohansen/silkscreen.pdf)
And I think the PCB's on the FIRST page of this thread is the same: Anode facing the two 6.8K and cathode the 100uF - like in my schematic - right ?
Maybe there is some later change/update ?

The original schmatic - some postings earlier in this thread - has the same values as in my schematic - where did you get those changes ?
Title: Re: Bo Hansen DI layout
Post by: Mondy on April 05, 2012, 08:39:04 AM
Hi Ksor

The positive supply for the whole circuit needs to be obtained from the cathode (K) of the LED and the 100uF cap should be from this positive rail to circuit ground. The anode (a) of the LED needs to be fed only from the common point of the two 6.8K phantom power resistors.

Cheers
Ray
Title: Re: Bo Hansen DI layout
Post by: ksor on April 05, 2012, 08:57:04 AM
Hi Ksor

The positive supply for the whole circuit needs to be obtained from the cathode (K) of the LED and the 100uF cap should be from this positive rail to circuit ground. The anode (a) of the LED needs to be fed only from the common point of the two 6.8K phantom power resistors.

Cheers
Ray

??? > Mondy

I still don't undersand - is the PCB in the link I gave wrong OR is you'r first posting wrong about the placing of the LED ?

Please, where did you get the changes in component values ?
Title: Re: Bo Hansen DI layout
Post by: ksor on April 05, 2012, 09:11:48 AM
OK - I can see some shopping lists has OTHER component values than the schematic - what a mess - what are the correct values - the list OR the schematic ?

Has the trafo to do with these changes - Sowter, Lundahl or Heufe ?

Title: Re: Bo Hansen DI layout
Post by: Mondy on April 05, 2012, 09:42:55 AM
Hi ksor

Here is my schematic I used to create my own board in Eagle.

(https://sites.google.com/a/noratel.co.uk/ray/Bo_Hansen_DI.jpg)

Please ignore the transistors as I used these just for the attached pad patterns for the custom PCB board I made. Here it shows the connection of the LED and the 100uF capacitor. I added a 100n capacitor in parallel with this capacitor for my version but this was not in Bo's design and can be ignored. The later component value changes are mentioned in Bo's website for the circuit and are just to keep the design updated etc. I used the specified Lundahl 1538 transformer and the DI sounds wonderful so keep up the effort on the build as the results are worth it!!

Cheers
Ray
Title: Re: Bo Hansen DI layout
Post by: ksor on April 05, 2012, 11:37:33 AM
Hi ksor

Here is my schematic I used to create my own board in Eagle.

(https://sites.google.com/a/noratel.co.uk/ray/Bo_Hansen_DI.jpg)

Please ignore the transistors as I used these just for the attached pad patterns for the custom PCB board I made. Here it shows the connection of the LED and the 100uF capacitor. I added a 100n capacitor in parallel with this capacitor for my version but this was not in Bo's design and can be ignored. The later component value changes are mentioned in Bo's website for the circuit and are just to keep the design updated etc. I used the specified Lundahl 1538 transformer and the DI sounds wonderful so keep up the effort on the build as the results are worth it!!

Cheers
Ray

OK and ofcause ... now I understand your point of the "positive supply" !

Thx  for guiding me - witch transistors did yoy in fact use ?

I go for this version when you have it working very well !
Title: Re: Bo Hansen DI layout
Post by: Mondy on April 05, 2012, 11:49:38 AM
Hi Ksor

I used the BC550C and BC560C transistors that Bo recommended (Fairchild and Motorola). The schematic shows 2 PNP devices because, as I mentioned before, the pad pattern was what I wanted in my board design so I used the schematic parts shown more for their patterns than the actual components.

Sound is great with acoustic guitar and Bo Hansen is a top man for this elegant and hopefully timeless little circuit!!

Best of luck with your build. I will try and post up some pics of mine when I get a little time!

All the best
Ray
Title: Re: Bo Hansen DI layout
Post by: ksor on April 05, 2012, 12:54:00 PM
I need 2 peaces of Lundahl 1538 !

Where can I get them these days for what prices incl. shipment to Denmark ?

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 06, 2012, 08:10:11 AM
Ksor,
Yes, Monday's have insert the LED right, but as I have tell many times before, use only a red LED, to get a minimum of voltage drop.


Monday,
Yes, I will draw a separate block schematic that will explain the electronics grounding theory.

Thanks for a nicely drawn schematic.
The added 100 nF in parallel with 100 uF is OK, but perhaps misleading because it is not on the PC layout.
And ofcourse the first transistor is marked as PNP instead of NPN, but it's easy to change.
There are also missing value (100nF) for the input capasitor and pin id (8) for the case/core ground on the Lundahl transformer.
It is also missing from the XLR-1 connecting pad, a connecting to the DI-box metal case.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Mondy on April 07, 2012, 05:19:45 AM
Hi Bo

I edited the schematic I posted for Ksor as you are right, it could cause confusion. The schematic was created solely to design the PCB board and therefore the components used were used for their PCB patterns only. I drew up an better version for the actual circuit below and I hope this may be of help. I'll take some pics of my build and post as soon as I can.

(https://sites.google.com/a/noratel.co.uk/ray/Bo_Hansen_DI_schem.jpg)

Cheers
Ray
Title: Re: Bo Hansen DI layout
Post by: ksor on April 07, 2012, 05:29:43 AM
Oh ... Mondy it's very nice !

Anyway you forgot  ;D the capacitor par to the 100uF  ;D ;D - but never mind - I know it's NOT on the original PCB,
but I have it in my Eagle and I have made a smaller PCB !

What's the difference between the XL and a normal trafo concerning sound ?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 07, 2012, 01:06:35 PM
Mondy,

Yes, now it's right, very nice schematic, can I use it on my tech page?

Just a small thing, it would be good if "chassis" connection is drawn directly on XLR pin 1.



Ksor,

LL1538XL has a larger core, and can handle more level in the low end compare with LL1538.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Mondy on April 07, 2012, 03:36:17 PM
Hi Bo

I have modified the schematic for the Pin 1 connection, I hope this is OK

Of course you may use it on your tech pages, it would be an honour!! Just let me know if you need anything further on the schematic and I will sort it out for you.

Thanks for a great DI!

Ray
Title: Re: Bo Hansen DI layout
Post by: 5cienti5t on April 21, 2012, 06:48:16 PM
Hello!

Bo, would it be correct to call your DI's transistor configuration a Darlington pair?  I understand that the first NPN's purpose is to provide high input Z, and has a low out Z.  The second, as you say on your site is to provide the necessary current to drive the transformer.  I would love as thorough of an explanation as you can muster - I'm presenting your project to my University's electronics class.  For example, one question I had was why there had to be two transistors - would the second be unnecessary if there were no output transformer?  Also, just curious as to why you have the less commonly used PNP instead of using two NPNs.

Also, I'm unsure of how the ground loop suppressor works.  You had said that you would like to post an explanation of this on your site - is there any news on that front?

Thanks so much, I can't wait to hear how mine sound!

This site is so cool and I love all of you for expanding my mind...
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 22, 2012, 02:13:29 PM
5cienti5t,

No, this is not a circuit with two transistors in the "Darlington" configuration, this is just two emitter followers dc-connected in a row.

The first transistor work at low current so that the base input allow the high-resistance bias resistors, which in turn permits the DI-box input impedance at 1 Mohm.

The second transistor works with almost 3.5 mA, which will guarantee for a good drive to the transformer, which reflects the load connected to the DI-box balanced output.

Why I used a NPN followed by a PNP is more a way I was thinking during the 1970's.
There have been some theoretical aspects concerning tempratur stability and linearity when one of each polarity is used, but in this application it would work equally well with two NPN.

The ground loop supression circuit works so that the 100 ohm resistor prevents it from going too high mains safety earth/ground current through the DI-box grounding system.
The 0.1 uF capacitor suppresses buzz and RF / HF frequencies and the two diodes are there to ensure that not the 100 ohm resistor is burning up in case of short circuit in an external device, and provide an opportunity for a fuse to blow up.

Btw, there is also a good circuit discription for this DI-box on www.hansenaudio.se/techpage.htm

--Bo
Title: Re: Bo Hansen DI layout
Post by: band_master on April 24, 2012, 06:25:59 PM
hey guys,
so i finished up one of my DI boxes last night and all is well so far. haven't tried connecting through to an amp yet though. quick question about strapping the grounds on the input...i am not sure how to do that with the jacks i got from mouser. they don't seem to have extra 'solder tabs' like the ones in Bo's pictures.

http://www.mouser.com/Search/ProductDetail.aspx?R=NJ2FD-Vvirtualkey56810000virtualkey568-NJ2FD-V

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 25, 2012, 07:18:56 AM
Band_master,

No, this jack does not have a switch function, you should instead choose Neutrik NMJ4HFS or a other good choise are Cliff CL1160A/S2BNB or Rean NYS2122.

--Bo
Title: Re: Bo Hansen DI layout
Post by: band_master on April 25, 2012, 02:19:22 PM
thanks, Bo!
Title: Re: Bo Hansen DI layout
Post by: band_master on April 30, 2012, 01:45:38 AM
hey Bo,
i have a question on the pad mod wiring. sorry i am not very good at reading chris' schematic. attached is a diagram of the wiring I have setup with a DPDT on-off-on switch. i am able to get the -10db pad setting to work, but the -20db setting is still -10db? can you tell me what i am doing wrong?

thanks,
BD
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 30, 2012, 03:29:55 PM
Band_master,

I changed your sketch, do this instead:

--Bo
Title: Re: Bo Hansen DI layout
Post by: band_master on April 30, 2012, 05:09:13 PM
awesome! thanks for doing that.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on May 27, 2012, 03:48:40 PM
This is amazing, it has now been over 50,000 views in this thread.

I'm very happy for your great interest in my Active DI-Box 1975.

Best from
Bo
Title: Re: Bo Hansen DI layout
Post by: scheppart on May 30, 2012, 09:20:39 AM
Hello everybody!

i want to build the DI box and i am about to order all the parts from one website. there is only one problem. the site has only 12V 1W zenerdiodes, no 500mw.
can i use the 1W or will this "destroy" the DI-box?

greetings!!!
scheppart
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on May 31, 2012, 02:30:01 PM
Scheppart,

You can use 1 watt Zener diodes, (or more) makes no difference in function, just make sure that they fit on the PC card.

--Bo
Title: Re: Bo Hansen DI layout
Post by: scheppart on June 01, 2012, 07:48:43 AM
thx for the answer =).

i wil not use the PCB Board. so there is no problem =)

greetz!

Title: Re: Bo Hansen DI layout
Post by: dirtyhanfri on June 01, 2012, 02:09:55 PM
Hi, I got a Behringer DI-1000 wich case will be for one of my 1975 DI's, and I found that the pcbs has 2 transformers, one blue, labeled OT-1 and the other one, smaller, black and unlabeled, the blue in the input and black in the output, could I use one of them for this design? if so, do I need to change any resistor values in the circuit?

Sorry for the generic question, but couldn't find any info on these...
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 01, 2012, 09:31:39 PM
Dirtyhanfri,

I have no knowledge of the Behringer DI-1000, also that it has two transformers seem strange, but if you can give me more information, so maybe I can give you any advice.

--Bo
Title: Re: Bo Hansen DI layout
Post by: dirtyhanfri on June 02, 2012, 03:50:57 AM
Sorry, but couldn't find any info about that, gonna look harder this afternoon, and if I got something interesting I'll post it here...

Thanks
Title: Re: Bo Hansen DI layout
Post by: Classicaudio77 on June 07, 2012, 12:04:02 PM
Has anyone tried using the Neutrik NTE4 or NTM4 transformers in this build?

These are 1:4 mic transformers that are rather easy to obtain here in the U.S.
I built 4 DI's. Two with the OEP, one with a Jensen, and one with a Neutrik NTE4.
The NTE4 is a small transformer with wire leads and only cost about $10.00
The NTM4 is labeled as "studio transformer", is PC mpunt, and is about $45 in a mu metal can
They had the NTE4 stock and I am waiting for the NTM4 to arrive (1-2 week lead time).

I was rather surprised with the sound of the NTE4. To my ears it sounded very close to the Jensen.
I like both the Jensen and Neutrik better than the OEP. The OEP sounds more rounded with less detail.
Will try the more expensive Neutrik NTM4 next week.

So far I have only tested these DI's on Bass.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 07, 2012, 03:30:33 PM
Classicaudio77,

These Neutrik transformers are very small and can be compared in quality with the old German 1:5 ratio transformers such as Beyer TR/BV-3.51.0.05.0300 or TR145/BV-35799 or MB/KeMo-4481.

Transformers of this size usually works very well in high-frequency end and goes high up with a good square wave response, but unfortunately the small-core gives poor headrom and quality in the low frequency end.

NTE4/NTM4 with ratio 1:4 may be slightly too low ratio in case the DI-box is loaded with too low impedance.

But as always, do you think it sounds good and is good enough for your purposes, then just carry on.

--Bo
Title: Re: Bo Hansen DI layout
Post by: scheppart on June 26, 2012, 01:11:16 PM
Hello,

i finished the di box today. and it does not work =(

i followed bo final test measuring.

my phantom power is 47,3v

where i should get 24V i get 45,5V.... (at the 6.8 resitors.)

has someone an idea where to start checking first? and what kind of problem this could be?

i have not used a PCB.
Title: Re: Bo Hansen DI layout
Post by: scheppart on June 26, 2012, 03:18:42 PM
update:

found a missing connection.

now i have 19.5 where it should be 24.
and 9.7 where it should be 12...

signal is coming through but with much background noise

i keep on searching....
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 26, 2012, 03:23:19 PM
Scheppart,

It sometimes happens that people who build the DI-box in other ways without using our pc-board, and instead do it with piont-to-point or on vero-board, are unable to get the electronics to work perfectly.

This is usually caused by wrong mounted transistors or reverse LED or that any connection is missed.

Since you have about +45 volts at the junction of the two 6.8 ohm resistors means that the electronics do not work and does not consume any current.

Check your building carefully, look also at our PC layout that you find here or on my tech page, where you can get a good idea of how everything is connected.

Good luck

--Bo
Title: Re: Bo Hansen DI layout
Post by: scheppart on June 26, 2012, 04:13:33 PM
thx for help bo!!!

have you seen my update.

i had one missing connection and one on the wrong side...

i have now 19.5 where it should be 24
and 9.7 where it should be 12

the signal is coming through! and sounds ok now. in fact much much much better then the hiZ input of my interface =)

Title: Re: Bo Hansen DI layout
Post by: scheppart on June 29, 2012, 06:52:38 AM
update again!

i have changed the interface and now i have: (from tascam us144 ref1 to rme babyface)

23,2 V
and
10,7 V

this is much better! but not perfect. as i  sayed the DI is working ( i guess). any suggestion where the error could be?

Greetings =)
Title: Re: Bo Hansen DI layout
Post by: useme2305 on July 09, 2012, 02:05:19 PM
is the Bo Hansen DI suitable for the LR Baggs magnetic active soundhole pickup? the pickup has an output load of 800ohms.
if not, is there a way to mod the DI to make it play nice with this pickup?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on July 16, 2012, 03:57:16 PM
Useme2305,

This pickup is already active with built-in amplifier/impedance converter, so if you only need an unbalanced output on the guitar, it works fine without any extra DI box.

But if you need a balanced output on the guitar to be connected directly to a mixing consoles phantom powered microphone input, in this case you need a good DI box, for example my DI box, which will be perfect suitable for this work.

--Bo
Title: Re: Bo Hansen DI layout
Post by: useme2305 on July 16, 2012, 04:33:37 PM
hey, i tried the pickup through one of my bo hansens and it sounds great.

i love your DI! i have three!
Title: Re: Bo Hansen DI layout
Post by: Mondy on July 17, 2012, 03:54:00 AM
Hi useme2305

I run a Takamine Triax pickup (which is a Baggs M1 but switchable to be either M1 or M1A) in passive M1 mode through a belt preamp 24dB gain stage (via a short 1.5 foot cable), then through Boss TU-3 for tuning and muting and then into my Bo-Hansen and the sound is just wonderful!! The Bo-Hansen and the M1/M1A work wonderfully together and as Bo said, the M1A or Triax in active mode will have a hot enough signal to go direct into the Bo-Hansen DI. 
Title: Re: Bo Hansen DI layout
Post by: lars78 on August 02, 2012, 08:39:00 PM
i had built a couple of Bo´s Di´s with different transformers, and now we did a little comparison.

24bit/88khz WAV
interface: Universal Audio Apollo
preamp: UAD apollo onboard
vovox instrument cable 

Git: Les Paul, neck P90 pickup
Bass: passive Yamaha 5 string Jazz Bass style 

transformers:
Haufe ST8456
Neumann BV-107 (09107)
OEP A262A3E
Beyerdynamic BV310 005 034
 
passive DI - Monacore DIB-100
passive DI - cinemag CM-DBX
UAD onboard JFET DI input

http://starfishcoffee.de/DI_Test.zip (http://starfishcoffee.de/DI_Test.zip)
http://starfishcoffee.de/DI_Test_fotos.zip (http://starfishcoffee.de/DI_Test_fotos.zip)

(http://starfishcoffee.de/Di6.JPG)
Title: Re: Bo Hansen DI layout
Post by: lars78 on August 06, 2012, 07:39:33 PM
Hello Bo !

I wanna build your Di-Box direct into a V672 preamp.
It is possible to connect the circuit without the TX to the preamp input

The input impedanz of the preamp is variable via choosing different "Re".
Wich is the correct input Z for the preamp ?

v672 Specs and wiring
http://starfishcoffee.de/v672specs.pdf

service manual and schematic
http://starfishcoffee.de/V672schematic.pdf

best Lars
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 08, 2012, 03:33:36 PM
Lars78,

Yes, you can do.

Remove transformer and the two 6,8K resistors, LED, XLR, and the componts around pin-1. (monitor jack and 10 K resistor)

Feed regulated +24 volt from the V672 pre-amp, and via a 100 ohm serial resistor connect positive 24 volt to + on the 100uF capacitor and negative/ground 24 volt to negative side of the 100uF capacitor.

Now you can feed the DI-box output signal from the negative side of the 10uF capacitor to the V672 input.

A input impedance around 10K will be fine.

--Bo
Title: Re: Bo Hansen DI layout
Post by: pablobolche on August 14, 2012, 08:44:30 AM
I just finished racking a dual ssl9k with Bo hansen Di.. pretty useful and great rack.. I was wondering how high can I go with the internal voltage for the DI as I have a psu I can omit the 10ma current limit.. From some experimentation I recall that the 3k9 resistor sets the internal voltage to 24v..
the thing is  I have some piezo pickup instruments that seem to go over the headroom for the DI and I think(could be wrong ) that if I lower the 3k9 resistor to XXX I would have a higher internal voltage and more headroom??
from the datasheet of the bc5xx it says i could go al the up to 50v no problem.. Is this reasonable or are there other issues to attend..
Gracias
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 14, 2012, 05:30:15 PM
Pablobolche,

This is a buffer amp / emitter follower with unity gain and operating on a supply voltage of 24 volts, this allows the input to receive a signal at about +19 dBu / 7.5 volts before the clipping level.

I guess a piezo pickup loaded with 1 Mohm has an output of about 1 volts when the guitar strings assaulted in the coarsest manner, and in this case you will have a headroom about 18 dB, and this is a lot of headroom for this purpose.

The 3.9 k resistor on the emitter of the last transistor is set to give a good drive for transformer types we use in this design, and this happens to be an internal voltage of 24 volts because the internal DI-box electronics consume 3.5 mA from the send and receive 6.8 k phantom resistors.

As an experiment, you can double the internal 24 volt supply to 48 volts with BC-550/560 transistors, and if you want the same current through the transistors that you have in the original design, just double the two emitter resistors 100 K and 3,9 k to 200 k and 7.8 k, or choose next regular value 220k and 8.2 k, in this case you get a huge headroom, but that is completely unnecessary for your application.
But of course this doubled voltage must be connected directly to the DI-box internal power supply rail.
Also note that 100 uF electrolytic capacitor must be greater than 50 volts.

--Bo
Title: Re: Bo Hansen DI layout
Post by: pablobolche on August 14, 2012, 05:59:23 PM
Great.. Thank you so much fro this di and for your reply.... Will do and post results...I have been havin fun and learning with this proyect...
Thanks  again...
Title: Re: Bo Hansen DI layout
Post by: mac on August 18, 2012, 01:27:02 PM
Has anyone tried Eds EA2622 in Bo's design?


Mac
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 21, 2012, 06:43:17 AM
Mac,

I'm sure EA2622 sounds good in my DI box if it is made as the original API.

The primaries (used as secondary in our case) can be connected in parallel or series, 150 or 600 ohm, so in parallel it have a ratio of 7:1 and give a loss of approx. 3 dB lower than Lundahl LL1538, and in series a ratio of 3.5:1 and have a loss of approx. 3 dB higher than Lundahl.

I would prefer conected in parallel for best output load match.

--Bo
Title: Re: Bo Hansen DI layout
Post by: useme2305 on August 21, 2012, 07:04:36 AM
i would include a Hi/Lo switch to have both options. or would that be totally dumb?
Title: Re: Bo Hansen DI layout
Post by: PdeP on September 13, 2012, 09:26:09 PM
Hi guys,

I'm planning to build at least three copies of this promising DI.
One is for my bass rig (live and recording).
I'd like to hook it up this way:
Bass -> preamp -> effects (output impedance 10 kOhm) -> DI (balanced to mixer) -> unbalanced to power amp (imput impedance 600 Ohm)

Would this DI work well in this setup? If not: What parts would I need to replace on the PCB?
Also, I'd like to insert a volume control between the board an the unbalanced amp output because the power amp doesn't have a volume control. Would a 100k lin pot with a 15 k resistor between Out and Ground work (see attached file) or which other values would you recommend?

Yours sincerely
S
Title: Re: Bo Hansen DI layout
Post by: audiophreak on September 17, 2012, 10:02:36 AM
Hello All,
             Was just wondering if replacing the 10uf electrolytic caps with Tantalum would make any difference  , just curious... any thoughts ??

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 18, 2012, 03:17:41 PM
PdeP,

This design in its simplicity is best just as it is, and is primarily intended to match a passive Hi-Z guitar or bass guitar to a Low-Z balanced microphone inputs with phantom power.

In your case that needs some more features, I recommend you something else that already have alternative inputs for line levels and outputs with level controls that can drive a power amp.


audiophreak

Today the usual aluminum electrolytics good enough and usually more reliable than tantalum caps.

I recommend that you select a good standard electrolytic like Panasonic FC or Elna RJH or something similar.

--Bo
Title: Re: Bo Hansen DI layout
Post by: audiophreak on September 18, 2012, 03:22:25 PM

audiophreak

Today the usual aluminum electrolytics good enough and usually more reliable than tantalum caps.

I recommend that you select a good standard electrolytic like Panasonic FC or Elna RJH or something similar.

--Bo

   Thanks Bo    :)
Title: Re: Bo Hansen DI layout
Post by: buildafriend on September 19, 2012, 11:02:49 PM
What is happening with all the parts in parallel with pin 1 to ground?

Any 24VDC secondary that is between 3-5mA should work, correct? What if I am powering two boards with one supply. Same?

 
Title: Re: Bo Hansen DI layout
Post by: mulletchuck on September 20, 2012, 12:06:45 PM
umm, isn't this thing powered by Phantom Power?
Title: Re: Bo Hansen DI layout
Post by: Dylan W on September 20, 2012, 11:07:51 PM
Having some trouble with my DI.

Had it sitting next to my Countryman type 85 near a clock radio, and the Bo Hansen was picking up significant radio interference where the Countryman was dead quiet.

No 60 cycle buzz, so I'm guessing it's not a grounding issue? But it shouldn't be this noisy. FWIW, I used plastic 1/4 jacks and a Hammond enclosure, and chassis earth is properly connected (to the chassis ground tab on the metal XLR).
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 21, 2012, 06:56:03 AM
buildafriend

I'm not sure that I understand your question completely right.

Are you saying that you should use DI box other than connected to a microphone input with phantom powering ?

In this case, you can run the DI box electronics with a stabilized +24 V voltage that is connected to the point where the two 6.8 k resistors are connected together.
-/ground 24 volts should of course also be connected to the ground rail on electronics.
(remove the two 6.8 k resistors if not using phantom powering)

You can run multiple DI box PC Card from the +24 volt power supply.
Be sure that the power supply of good stabilized type.
Each DI box card draws only 3.5 mA, with a PSU that can handle 100 mA load, you can run some 20 of the DI box cards.


Dylan W

I assume that the box you have built-in the DI box electronics/PC-card in it is a metal box, and the box is connected to ground according to my instructions that you find on www.hansenaudio.se/techpage.htm

When you hear the interference from the clock radio, do you have any guitar or cable plugged into the input ?

If nothing is connected to the input, are the input jack is shorted to ground with the switch/brake function in jack ? (see my instructions)

What kind of transformer did you use ?

Do not know if you have access to an oscilloscope, but it would be good if you check the electronics so it does not self-oscillate for some strange reason.
This can give rise to the radio and DI box found each other.

--Bo
Title: Re: Bo Hansen DI layout
Post by: glbaudio on September 21, 2012, 05:25:56 PM
Hey,

Just though I would post a pic of my finished units. Black model is with Lundahl, silver is with Haufe. Thanks for the awesome design.
Great boxes! where you bought them? company?
Title: Re: Bo Hansen DI layout
Post by: Dylan W on September 21, 2012, 06:08:05 PM
Thanks for the reply, Bo. I built it all to spec. The interference was with a bass plugged in. Went to test it again, but it was quiet as the grave! I've notified the studio ghost that he's under investigation. Meanwhile, I had everything set up, so... shootout time!  ;)

One is the Bo Hansen DI with OEP tx, and the other is the Countryman Type 85 (both requiring +48).

http://soundcloud.com/dwshootout/sets/bo-hansen-vs-countryman

Tech specs: The preamp is Jeff's Classic API VP28. Input gain was left the same. Performances are not the same but close enough. Clips are level matched fairly closely with Voxengo SPAN. If you want to run more tests or level match yourself, I've enabled downloads. Bass is a Fender P with flats. Guitar is an Epiphone Wilshire reissue, and is pretty badly out of tune (sorry).
Title: Re: Bo Hansen DI layout
Post by: jonwormwood on October 02, 2012, 12:10:57 PM
So I finally finished my DI. It sounds great! Super clean, no buzz.

The only thing is it's a tad thin then straight to the amp (high gain pre amp) I still need to check the voltage on the test points.

I'm using the haufe trans.
Title: Re: Bo Hansen DI layout
Post by: Matador on October 02, 2012, 04:44:44 PM
What is happening with all the parts in parallel with pin 1 to ground?

Not sure if I saw an answer to this:  this is explained pretty well in Rane's grounding article:

http://www.rane.com/note151.html (http://www.rane.com/note151.html)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on October 03, 2012, 01:33:39 PM
jonwormwood,

Are you saying that the DI-box sounds thin when you connect the "Amp Out" (unbalanced output jack) to the input of a guitar amp?

If the DI-box sounds great from the balanced XLR out connector, in this case should also the unbalanced jack sound good, because it's the same signal except the transformer.

--Bo
Title: Re: Bo Hansen DI layout
Post by: buildafriend on October 11, 2012, 11:46:11 PM
buildafriend

I'm not sure that I understand your question completely right.

Are you saying that you should use DI box other than connected to a microphone input with phantom powering ?

In this case, you can run the DI box electronics with a stabilized +24 V voltage that is connected to the point where the two 6.8 k resistors are connected together.
-/ground 24 volts should of course also be connected to the ground rail on electronics.
(remove the two 6.8 k resistors if not using phantom powering)

You can run multiple DI box PC Card from the +24 volt power supply.
Be sure that the power supply of good stabilized type.
Each DI box card draws only 3.5 mA, with a PSU that can handle 100 mA load, you can run some 20 of the DI box cards.

--Bo

To save money I decided to use the DI just like most people and run it off of the phantom power. I put the DI together today (took about 2 hours, it was very strait forward) and it powers on when fed the phantom power juice. I'll be testing soon.

Thanks!

PS, I think what was wondering about might just be a simple transient suppressor?
Title: Re: Bo Hansen DI layout
Post by: heavyriderdiy on January 23, 2013, 05:08:34 PM
Hi,
after hours of reading here, i've just finished a stereo direct box. i went for a pad option (0,-10,-20) just in case of for live situation.transformers are Lundhal 1538 XL
we tested it quickly yesterday night on a "L acoustics" PA with an electro acoustic guitar, and we had a LA Audio direct box to compare. where the LA Audio was a bit blury the sound of the bo Hansen box was full, well defined.
i can't wait to use it on other sources.
thanks Bo for this simple but efficient design.
thanks to Gustav for making things easier
(http://i54.photobucket.com/albums/g93/heavyrider/photo56_zpsf0d3093e.jpg)
(http://i54.photobucket.com/albums/g93/heavyrider/photo55_zps90c63da5.jpg)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 26, 2013, 07:15:33 PM
heavyriderdiy,

Thanks for your response, I am glad to hear that you like my old DI box design.

Of course we should not forget Luny Tune, Soeren_DK and Gustav that has made it possible to buy ready-made PC-card for this project.

It is also amazing that more than 61,000 have read this thread.

--Bo
Title: Re: Bo Hansen DI layout
Post by: osso1001 on February 02, 2013, 06:24:08 PM
Hi Bo.
I start with a big thank you for cheering your DI, and for sure also all the guys helping to make it assessable to all.

Well, to Bo, or anyone with some ideas...
 I'm building one of your DI's and just had a doubt...in the PAD mod. I saw how to do it, but was wondering if insert it in the Input, you are, I guess, also Pad'ing the output to the Amp, right?, nothing wrong with that, but if you do the same schematics doubled (for 2 and 3,from XLR -signal/inv.), do you think that would work too?

Thanks in advance,
Mario
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 02, 2013, 10:07:26 PM
Mario,

The PAD we have used is inserted on the input and is a simple unbalanced voltage divider formed with resistors.

Would you rather have a pad on the output, it will be the same as the PAD normally present on the microphone input of a mixer or preamp.

The difference is that a PAD on the DI box's output must then run a long microphone cord, and this may not always be the best solution.

This DI box does not really need any PAD for its own sake, because it can take a level close to +20 dB on the input before clipping, and it is 10 times more than what a guitar or bass can provide.

But it can overload the input of a mixer or pre amp if a a synthziser or keyboard is connected to it. (or guitar pickups with extremely high output)

But if there is a PAD on the mixer or pre amp, it will work well to get this right.

So the answer to your question is, use the recommended pad on the DI box input, or simply use the existing PAD on your mixer or pre amp.

--Bo
Title: Re: Bo Hansen DI layout
Post by: osso1001 on February 03, 2013, 08:22:36 AM
Thanks Bo,
I guess you right... I can always pad at the mixer/preamp.
I guess I'll try one with no Pad, and one at the input just for the special cases the might appear.
Well thank you again for all.
regards,
Mario
Title: Re: Bo Hansen DI layout
Post by: kante1603 on February 09, 2013, 09:41:45 AM
Hello,

thought I should share this.I have done quite a few of Bo´s D.I.-Boxes now and I like them very much.But always when I´m checking things in my 51x-Racks/listening to some music I have to look for these little beasts first and search them,hahaha... ;D

So I decided to make a 51x compatible dual piece that will reside in the "11th" slot forever.
Just 1 module wide,I used a gender changer to convert the female XLR on the back to male.A passive piece of course,powered by the mic-pres.

I had some two leftover pcbs already here.So I ordered some stuff like L-Brackets,Haufe transformers and a prototype pcb (goldfingers) from Volker (silent:arts) and "designed" a frontpanel which was done by Frank at NRG-Recording as always.
Here´s the result,it really was a fun to build.

Cheers,

Udo.
Title: Re: Bo Hansen DI layout
Post by: kante1603 on February 09, 2013, 09:42:44 AM
The guts:
Title: Re: Bo Hansen DI layout
Post by: kante1603 on February 09, 2013, 09:43:38 AM
...and racked:
Title: Re: Bo Hansen DI layout
Post by: useme2305 on February 10, 2013, 09:17:23 AM
why did you decide to make it get its 48v from the mic pre instead of the 48v rail?
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on February 10, 2013, 09:56:19 AM
why did you decide to make it get its 48v from the mic pre instead of the 48v rail?
same question - or even better: the +24V rail?
Title: Re: Bo Hansen DI layout
Post by: kante1603 on February 10, 2013, 11:45:06 AM
Just to make sure I couldn't feed phantom twice or from different sources.
I thought about this for a while and decided to go this way,same as I'm used to do with external active D.I.s. meaning to switch phantom on the pre.

Udo.
Title: Re: Bo Hansen DI layout
Post by: CheapChip on February 13, 2013, 05:11:49 AM
Hi,

First, many thanks to Bo for giving us such a great design!

But I've finished my build few days ago, and have a problems I don't manage to solve:
When my DI is powered on, LED light is on but weak.
Then there's a sort of white noise and a little hum growing up when the metal box is touched or when an instrument is plugged in.
And last but not least, the instrument's sound is distorded (not really bad sound but not really what I was looking for).

Transistors and zener diodes were changed twice, BC550 and BC560 were even sweeped with BC547 and BC547, 3 PCB were etched and resistors are verified.
Can the transformer (OEP A262A3E) be the faulty part?

Any idea Doc, I'm going to be crazy!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 13, 2013, 04:32:04 PM
CheapChip,

Must ask some questions to find out more about your problem.

I assume you connected the DI-box to a true balanced microphone input with functioning 48 volt phantom powering.

Have you built up the electronics on the Group DIY original PC board ?

Have you grounded metal box in the pc-board terminal "chassis" and not in any other ground / earth point ?

Have you connected the XLR connector pins 1, 2, 3 to the PC board terminals "XLR out" in the right order ?

Have you turned all the transistors, diodes, LEDs, electrolytic right way as marked on the original PC board ?

If you have a voltmeter / DVM, you should measure over 100 uF capacitor (set to dc volts) around 23-24 volts.
Also measure from the BC560 transistor emitter to ground about 11-12 volts.
If these two measurements are correct, should the two transistors  work right.

--Bo
Title: Re: Bo Hansen DI layout
Post by: CheapChip on February 13, 2013, 06:16:29 PM
Thanks Bo for your quick reply!

So, to answer your questions:
Yes my PCB's are etched from files posted at the beginning this thread.
Yes my DI box is connected to a microphone input with a decent 48v phantom power turned on.
XLR pinout connections seem to be ok.
And PCB is grounded with "chassis" point connected to metal box by the XLR ground pin.
And every component seems to be at its place according to documents.

For now, I can't proceed to voltmeter measurments.
I'll post results as soon as possible.

Thanks again!
Title: Re: Bo Hansen DI layout
Post by: CheapChip on February 14, 2013, 03:02:04 AM
Hi everyone!

So here is what I found:
Phantom power: 47.4v
100uf cap: 10.4v
BC560 (BC557 actually) emitter: 5.1v-5.2v

It looks like there is a problem with transistors, but it is the third pair I use.
1st pair: BC550/BC560, 2nd: BC550/BC560 (same bag as the 1st pair), 3rd: BC547/BC557 from an old stock I had.  :-\

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 14, 2013, 03:13:01 PM
CheapChip,

Ok, you have too low internal supply voltage.
This may be due to something on the PC board drawing too much current, and then there will be large voltage drop across the two 6.8 k resistors.

But while you say that the LED is dimly lit, if something were to draw a lot of current, so would the LED brighter instead.

Are you sure it is a normal red LED you have used, and that it is connected in series with the voltage rail as described on pc-card?

Are you sure the two 6.8 K is right, so it's not 68 k instead ?

Are you sure there are 1N4004 diodes and a 100 ohm resistor which is mounted on the PC board ?

Make additional measurements.
Once you have the DI-box connected to the microphone input with 48 v phantom powering, you should measure between XLR pin 1 and pin 2, and pin 1 and pin 3.

Tell me what you get for voltage at these points.

--Bo
Title: Re: Bo Hansen DI layout
Post by: CheapChip on February 14, 2013, 05:33:31 PM
Ok Bo!

I'll check it all and give you these measurements on tomorrow morning.
It's 11:30 PM here in France, and my tools are just stocked under my daughter's bedroom...  :-[
(I think it's time to have a workshop...)

Thanks again, Bo!
Title: Re: Bo Hansen DI layout
Post by: CheapChip on February 15, 2013, 03:07:00 AM
Hello!

All I can say about the red LED: a 5mm (that seems to be) standard red LED that I picked up from an old answering machine.
It is connected with 2 wires as described on silk screen.

6.8k resistors checked: 6.7k with multimeter

1N4004 are OK and 100 ohms restitor checked at 101.7 ohms are correctly in place.

Measurements of XLR pins:
From 1 to 3: 32.8V
From 1 to 2: 0.03V (39.2mV)  ???

Thanks!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 16, 2013, 11:33:15 AM
CheapChip,

The voltage around 31 volt you get between XLR pin 1 to 3 is correct, but it should be same between pin 1 and 2.

In this case it can only be a fault in your microphone cable, or the XLR connector on the preamp/mixer, or one of the 6,8 k resistor in your preamp/mixer.

Try to do a measure direct on the unplugged cable in the female end.
(ofcourse plugged in preamp/mixer end)

--Bo
Title: Re: Bo Hansen DI layout
Post by: CheapChip on February 17, 2013, 03:53:28 PM
Hi  Bo,

I said in my first post that I was going to be crazy but for now, I'm a fool...

I made new measurements between XLR pins and I saw I had about 30 volts on PIN 2/PIN 3.

I checked wires between XLR plug and PCB for the 4th or 5th time and realized that ground was in place of the negative pin and vice versa... Mistake corrected: my DI box is ... quiet and sound is ... clean.  :-[

I'm really glad it works, but ashamed you wasted your time not on a problem but a mistake.
Again I apologize for it.

Thank you again, Bo, for this wonderful project and for your help.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 17, 2013, 06:54:36 PM
CheapChip,

No promblem, happy to help.
The main thing is that you get your DI box construction to function as they should.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Sandersonic on April 16, 2013, 04:27:32 AM
Here's my newly completed take on this project. I've used the Lundahl 1538XL and implemented the pad-mod mentioned earlier in this thread. I built it, plugged it in and it worked silently and perfectly straight away. This is an excellent circuit design and the kit from Gustav at PCB Grinder makes it an absolute breeze to build. I also very much recommend the XL variant for the transformer. Particularly whereas electric bass often gets lined and the extra low-end headroom is good to have. Also, the pad is a very good idea since this unit (or at least my build of it) puts out a lot of signal! Especially with, for example, an electric bass with active pickups.

Title: Re: Bo Hansen DI layout
Post by: audiophreak on April 16, 2013, 09:10:22 AM
Hello,
       I've completed a dual unit of this wonderful DI and it sounds fantastic, have used it on several sources and it just excels , however I have checked some voltages as described on Bo's page :
   " Use a digital voltmeter in dc mode and connect the negative test cord to the input jack ground and the positive test cord to the junction av the two 6,8k resistors, or the long leg of the LED if this is used, or the link if the LED not used, and here you should measure +24 volts, +/- 1 volt, if everything works ok.

The next measurment is to check symetrical clipping and headroom.
Move the positive test cord to the junction of 3,9k resistor, 10uF capacitor positive end and emitter on BC560 transistor, and here you should measure around +12 volts, +/- 0,5 volt. "

    In checking the phantom power from the console unloaded its about 50vdc , both circuits without an LED I get 25.77vdc at the 6.8k resistors and 12.96vdc at the 3.9k and 10uf junction.
  With the LED in circuit I get 27.9vdc and the 6.8k resistors and 11.92vdc at the 3.9k/10uf junction.

EDIT :   Phantom voltage when unit is connected to console is 37.74vdc without LED and 38.8vdc with LED

  I am using a 3mm red LED with a 780oHm resistor in line for 24vdc operation.

  Do these voltages seem correct ??  I mean it works and all , just want it to rock solid  :)

  Thanks,
              Chip

 ps ...   Beautiful unit Sandersonic  ;)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 16, 2013, 12:58:51 PM
sandersonic

Thanks, I'm glad you like my DI box design, hope you will enjoy using it on many recordings.


audiophreak

Your measured voltages are ok, it does not much matter if the voltage varies quite a lot in this circuit, only they do it propotionelt up and down as the specified voltage value I have stated.

What will happen if phantom powering is lower or higher is that the DI-box electronics gets more or less "head-room", and the power consumption changes up or down.

The fact that your measurements are slightly higher is because your phantom power is a few volts higher.
The voltage I have given are measured at exactly 48 volts from the mixing console/preamp. (measured when nothing is connected)

The "phantom power" on the DI-box XLR pin 2 or 3 is about 36 volts, the voltage varies a tad if you use LED or not, and if you use LEDs of other colors.
And it will increase if you connect a series resistor to the LED.

Note that shall NOT be any resistor in series with the LED, it will just be connected as it is marked on the PC card.

Use always a red LED, because it has lowest voltage drop of all colors and steal minimum voltage from the supply rail.

--Bo
Title: Re: Bo Hansen DI layout
Post by: audiophreak on April 16, 2013, 04:55:48 PM
Bo,
    Thanks so much for getting back so quickly , I was using red LEDs, but thought a series resistor was always needed for voltage applied.
    I removed series resistor and got 26.68vdc at 6.8k resistors and 12.48vdc at the 3.9k/10uf junction.
  All is well and Thanks for this great sounding project, I will be building another pair real soon, and will post pics soon too !!     ;D

 
Title: Re: Bo Hansen DI layout
Post by: 00940 on April 22, 2013, 08:07:32 AM
Hi,

I'm about to build a pair. They are intended for live use (guitar, keyboard, connection with local pa system, etc...). I'll use the oep transformers. But the guy in charge is worried about ground isolation (he's been spoiled with bss ar133 in the past but money is harder to come by now).

An isolated dc-dc converter (such as this one http://www.reichelt.de/DC-DC-Inverters/TMA-1212D/3/index.html?ARTICLE=120453 , using the +/-12v in serie to get 24v) would offer true isolation. I'd use 6k8 phantom resistors and a 12v zener in front of it and some lc filtering at the output. Total current draw of the DI would be around 5.3ma. The other option is to use batteries but they have the sad habit to run down right when they shouldn't.

But is it really a good idea or should I just build the DI in stock form ? Is the groundloop breaker effective enough for stage use ?

Thank you in advance for any comment   :)

Ben

PS: I didn't know if it was a better idea to create a new thread or post here... sorry if I picked the wrong option   :-[
Title: Re: Bo Hansen DI layout
Post by: Harpo on April 22, 2013, 09:06:18 AM
Just some reason (there are some other) why it might not be the best idea:
When you add the -from Traco datasheet- 12mA for input current no load to your 'Total current draw of the DI would be around 5.3ma', you run out of beef with your mixer only/maybe delivering 10mA phantom current. Short circuit protection 1 sec.max. might be the next bottleneck. With your additional L/C filter you already exceeded the 100uF max.capacitive load.
Title: Re: Bo Hansen DI layout
Post by: 00940 on April 22, 2013, 11:20:32 AM
I learned a lesson. today.. don't request other letters in the confirmation form before posting. Your long message might disappear  >:(

Back on topic. You're definitely right, I overlooked that point in the datasheet.

One possibility might be the LME0515/LME1215 (found on Farnell and mouser). Output is only 15vdc/16ma for 5 or 12vdc input but the no-load current is 2.5ma (according to the C&D datasheet, the murata datasheet is silent on that). Total load (circuit+converter) would be just under 8ma, which is ok with smallish phantom resistors.  That could work, with reduced headroom. But well, I'm just writing this down for reference... 2x9V batteries don't seem so bad anymore. I'll build them stock for now and see what happens.

Thanks.  :D

Ben
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on April 22, 2013, 11:56:35 AM
You could just use an external 24V PSU  ;)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 22, 2013, 03:30:50 PM
Ben,

Start to build my DI box in original version with our PC card, and follow my instuctions carefully describing grounding and housing etc. www.hansenaudio.se/techpage.htm

I think you will be satisfied with the suppression of hum, buzz and noise.

--Bo
Title: Re: Bo Hansen DI layout
Post by: 00940 on May 19, 2013, 08:42:10 AM
Well, it took a month to get to work (the build itself just took about 3 hours for the pair) but here they are.

No-frills version, transformers are OEP (from Farnell, Canford wouldn't sell to someone without VAT registration), all connectors neutrik and the box is a Hammond 1590C. I might add a 20db pad in the future if the need arises. Construction was very easy thanks to the pcb and the detailled instructions. As usual, the worst part was making the holes for the xlr jack (with only a hand drill and a metal file, yuck). They won't win any beauty contest but they work and that's all I need.

Thanks a lot to Bo for providing both the design and such clear build instructions.
Title: Re: Bo Hansen DI layout
Post by: frans on June 06, 2013, 02:08:57 PM
I couldn't resist to show off my Pirate D.I. - iron is the the Haufe from Volker, board and parts from pcbgrinder. The top is acrylic glass cut by Frank from nrgrecording, laminated print underneath. Box from Hammond.
Title: Re: Bo Hansen DI layout
Post by: flaheu on June 07, 2013, 03:12:11 AM
cool !

Is Bo really looking like that ?
and..........where is sponge bob  ;D ;D
Title: Re: Bo Hansen DI layout
Post by: kante1603 on June 07, 2013, 04:08:24 AM
Pipi lebt!

Udo ;D
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 07, 2013, 04:28:14 PM
Sure, it's me as a young hippie with long flowing hair and beard, now I'm old and bald with stubble.

Best from
Bo
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on July 15, 2013, 05:36:35 PM
Hi guys

I have built two of these DIs, and I love them very much! Both have been working without a problem, so I decided I wanted to rack them and maybe add two more into an old 1U chassis I never used. I got the first two mounted (keep in mind that in their own individual enclosures, they wore working fine), and now there appears to be some strange ground noise. I haven't done anything different from the grounding scheme mentioned on Bo's page, I just took the two circuits and put them in the same box. When I used two separate sources, there was no problem, but when I put the left and right channels of a stereo keyboard into the two inputs on the box, i got the noise.

Are there any additional considerations I need to observe, or should my 'dual mono' style unit work as planned?
Title: Re: Bo Hansen DI layout
Post by: kante1603 on July 15, 2013, 09:04:36 PM
A pic might help,maybe non-isolated jacks?

Just a thought,

Udo.
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on July 16, 2013, 12:59:42 AM
Alas, I am not near them... Nor will I be until the weekend :-\

I DO know the jacks are isolated per the instructions, remember, the two individual DI circuits worked until I put them in the same case. I Should mention that I've used the Jensen JT-13k6-c. If I made a mistake, it would likely be related to that, because all the jacks are isolated like they were supposed to be.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on July 16, 2013, 02:30:28 PM
jasonallenh,

Normally it should not be any problems with ground loops between the equipment in the studio and control room, even if two or more DI- boxes mounted in the same metal housing.
But it is important that you use insulated tele-jacks, and followed my grounding instructions.

A other thing you must need to know is that the ground suppressor in this DI-box works the same way as a ground lift switch does in other types of DI-boxes, meaning that it breaks up the ground system between DI-boxand mixing console, but it is still a normal grounding system between the instrument input and the amplifier output jacks.

For this reason, you can get ground loop problems that result in hum or buzz if you for example connect two amplifiers, one to each DI-box amp output jack, and if these amps have earthed mains cables connected to earthed wall sockets.

Similar problems can occur if you have mains connected effects devices or synthesizers connected to the input jacks.

But if it is important for you to use multiple monitors/backline amplifiers connected to the DI-boxes in the same housing, you can add a similar ground loop suppression circuit as you can see between the XLR connector pin 1 and PC-card ground rail, and do same trick for the ground sleve terminal on the amp out jacks.
(use all four components, 2x 1N4004, 100 ohm, 0,1 uF)

--Bo
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on July 16, 2013, 10:03:58 PM
Bo!

Thanks so much! That's a lot of useful information. I'll put it to good use.
Title: Re: Bo Hansen DI layout
Post by: anjing on July 16, 2013, 11:44:21 PM
My hat to Bo!

  Just build one Di with the pcb i got from Gustav. It sounds stellar trough Ian's eztube preamp.

Great thanks for making this available.

Regards,

Pierre
Title: Re: Bo Hansen DI layout
Post by: Esoterimix on August 16, 2013, 08:04:29 PM
Anyone got some of these PCB's in the US? I don't really want to etch my own, call it laziness ::smile::
I would like to get my hands on a couple of these if possible... Or even if someone is down to etch one for me.

Before you say it, I know I could use a perf board or something of the like, but screw that... I want these to look professional. I really like the concept of the D.I. and I'm trying to build several different styles of D.I. after this one, it's on to a Tube based D.I. (like, maybe, REDDI)... Send me a pm or e-mail me at Esoterimix [at] gmail [dot] com

Thanks in advance!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 19, 2013, 08:16:06 PM
Esoterimix,

I am sure that our PC-board guy Gustav does not have any problems to quickly and easily send the original PCB directly to the U.S.

Here is the direct link:
https://pcbgrinder.com/index.php?route=product/product&path=59&product_id=58

--Bo
Title: Re: Bo Hansen DI layout
Post by: Esoterimix on August 28, 2013, 04:55:55 AM
Just got two boards from Gustav in the mail today... Very excited, getting the BOM all sorted. I'm already rolling designs for the outside of the box in my head.. Should be interesting... This will easily be the most painless project on the work bench. It really is awesome to have people like Bo and everyone who makes this community possible. p.l.u.r.
Title: Re: Bo Hansen DI layout
Post by: Esoterimix on September 15, 2013, 01:37:54 AM
I have . question... I saw the dB pad schemo someone posted and it had an RC for the -10 I believe...just curious, but would that basically act as more of a filter than a pad?
the cap shown os 18 pf  with a large resistor, does the last on that just work out to be avalue that pretty evenly pads across the necessary frequency band width because I thought there would be a slope at like 6db per octave....
also, if I.built the pad (on a eurocard I sized with a dremel) could someone check the wiring?

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 15, 2013, 08:31:10 AM
Esoterimix,

A 2.2 meg resistor connected in series with the input of my DI box that has an input impedance/resistance of 1 meg will attenuate the signal 10 dB.

But since this is a high-ohm voltage divider it also provides a treble loss.
This is corrected with an 18 pF capacitor in parallel with the 2.2 meg resistor so that the PAD will get flat response again.

If you connecting a 330 kohm resistor after the 2,2 meg/18 pF to ground, you get an additional 10 dB of attenuation, which in total will be 20 dB.

You can find a complete solution here: http://www.groupdiy.com/index.php?topic=36569.msg467685#msg467685

But consider that this DI box can withstand lot of level on the input before the electronics choke/clipping, so if the signal to the console's mic input is too high, and if you have PAD on the console, use that instead, it usually works well many times.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Esoterimix on September 16, 2013, 01:24:54 AM
wonderful. thank you for the quick response. I found the schematic already but the cap seemed pf however, you've cleared it up. I doubt I'll need a pad anytime soon, but I want the practice. gonna use a dremelry tool and eurocard to make it. Ill post pictures when i get that done....

gotta say, Bo, the box sounds fantastic for both live and in recording applications.  thanks.
Title: 3 di 's done
Post by: dribro on September 29, 2013, 06:08:30 PM
hello everyone

thanks a lot to Bo Hansen and others for making this possible. The 3 units sound good, even the pikatron revealed a great tone !
Title: Re: 3 di 's done
Post by: kante1603 on September 30, 2013, 01:32:11 AM
Nice colours,congrats to yout builds!
Yes,pikatron are good transformers indeed.
But why did you make a groundlift?

Udo.
Title: Re: Bo Hansen DI layout
Post by: dribro on September 30, 2013, 08:04:08 AM
thanks!  yeah,  I know it defeats the loop suppressor feature... but as I intended to use all the hardware of the thomann boxes, as it doesn't have plastic connectors for the TRS's, as safety measure I left and ended up using the switch. Oh well maybe I'll change it later. Pretty neat little things!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 30, 2013, 11:18:26 AM
You must keep in mind that a "thru" Ground Lift switch that disconnects the XLR pin 1 does not work well in an active DI box.
(it works just fine for passive DI boxes)
This is because the pin 1 not only serves as ground connection to cable screen, it is also the negative/ground wire for phantom power.

If the XLR pin 1 is "ground lifted" must phantom negative/ground find a different and longer route, to get the phantom power to the DI box.

An example of a possible long route is via the mains plug earth connecting on the mixing console psu, and then through the house's electrical system to a guitar amp mains plug earth connection, and then the amplifier's input is connected to the DI-box "amp monitor out".

This can cause the DI box does not work, get lower supply voltage or becomes unstable, more sensitive to radio interference, buzzing from light installations, etc.

Do not overlook my "ground loop suppressor" is smart and works very well in an active DI box compared to a conventional ground lift switch.

--Bo
Title: Re: Bo Hansen DI layout
Post by: dribro on September 30, 2013, 01:30:30 PM
thanks! got to get it right then!

best
Adriano
Title: Re: Bo Hansen DI layout
Post by: CurtZHP on October 03, 2013, 05:13:08 PM
Just got done building my own.  First, a huge thank you to Bo for making this design available.  A fun, quick and easy build.

I used the OEP transformer in mine, simply because I wanted to use it for something.  I had just taken it out of my Gyraf G7 microphone, having upgraded that to a Lundahl.  So I had the OEP, and I was thinking, "What can I do with this now?"  I did a search on the forum, and found Bo's design.  Perfect!  I could use a direct box, and for about $10 in additional parts (I already had the metal box and the connectors) I set to work.  I etched my own board.

A couple questions....
I connected a wire from the "chassis ground" point on the PCB to the spare lug on the XLR, then ran a small jumper from that to Pin 1 of the XLR.  From what I've read here, this is correct, right?

I checked the voltages per Bo's instructions on his site.  On the "hot" side of the LED, I measure about 22VDC.  At the junction of the 3.9K resistor, the BC560, and the 10uF capacitor, I read about 10.9VDC.  Are these good?

When I connected it to my console (Tascam DM-24) and plugged my bass in, I noticed that I had to turn the preamp gain up very high to get a decent signal, and it clipped quite readily.  I didn't worry too much about it, because my experience with inexpensive console and interface preamps has been very similar, especially when using dynamic mics.  Connecting the DI to my Paul Stamler designed mic preamp yielded a much better result.  That said, short of getting rid of the red LED, is there anything else I could do to give this box a little more "oomph" when using it with less than ideal preamps?

Thanks again, Bo!

 :)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on October 05, 2013, 03:13:55 PM
CurtZHP,

Thank you for enjoying my DI box design.

Your description of the ground connection seems to be quite accurate.

The voltage value you measured is quite ok, and remain within normal limits.
If the voltage over 100 uF capacitor is 22 or 26 volts, does not matter much, the main thing is that you have approx. the half of that voltage on the final transistor emitter. (at the junction of the 3.9K resistor, the BC560, and the 10uF capacitor)
In this case the electronics are functional as it should, clipping nicely and gives the most output swing.

I always go on about that you should use a red LED, as this gives a minimum voltage loss of all LED colors.
It makes no noticeable difference with or without this red LED, but if it starts to get a number of voltage drop in some weird colored LED, this may affect the DI-box output swing/head room, although it gets very little.

About low output.

About 14 dB loss from the high-Z input to balancsed output is suitable for a DI box that will feed into normal microphone input.
If the DI box has no loss, a guitar with high output microphones almost give 1 volt to the microphone input, in extreme cases, and this is too much.

Lundahl LL1538 and Haufe ST8456 provides approx. 14 dB loss in this application, but OEP A262A3E provides further 2 dB loss, and may appear to be somewhat weaker.
The OEP transformer has a very good quality for its price, even compared to the other two.

--Bo
Title: Re: Bo Hansen DI layout
Post by: CurtZHP on October 05, 2013, 04:10:58 PM
Great to know.  Thanks!

Like I said, I wasn't too surprised, considering the quality of preamps in my console.  They are OK, but not great.  And even with a condenser mic, I usually have to turn them way up.

Title: Re: Bo Hansen DI layout
Post by: sisepuede on October 12, 2013, 03:19:36 PM
Hi Bo,

Thanks a lot for this DI Project.

Is it possible to do this DI box using Jensen JT-DB-E wich is a Direct Box transformer and also coz I have several of them...  ;D ?.

I would like to use the Bo Hansen DI on Bass Guitar wich is at least 1 megohm Z.

Cheers!

Guillermo
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on October 13, 2013, 02:15:15 PM
Guillermo,

Sure you can use Jensen JT-DB-E transformer, but since it has a ratio of 12:1, it has unfortunately too much gain-loss for an active DI box, approximately 22 dB.

This transformer is made with high ratio to load a guitar/bass as little as possible when it is used in a passive DI box. (according to Jensen 140 Kohms when it is loaded with a 1 Kohms mic input)

What impedance guitar or bass to be loaded with is a matter of taste, passive and active DI boxes with impedances between 100 Kohms tuill 10 Mohm, color the sound at various brands and models of instruments.

I personally think that 1 Mohm is a good compromise to load conventional passive guitars and basses with, especially if you only have access to a DI box in your studio.

Of course, you should have several types of DI boxes, as this is a great way to bring out a special character of an instrument.
(the same way that you choose a microphone for a specific sound source)

--Bo
Title: Re: Bo Hansen DI layout
Post by: sisepuede on October 14, 2013, 10:53:42 AM
Hi Bo!

Thanks a lot for your nice and fast answer, seems like I should get a LL1538 and leave the jensens on the D.I as they are :).

Cheers!

Guillermo
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on October 20, 2013, 11:34:48 PM
Hi Bo,

Speaking of Jensens... I'm trying to wire one up with a JT-13K6. I have to use it 'in reverse,' so I was hoping you could clarify how to connect it.

http://www.jensen-transformers.com/datashts/13k6c.pdf

What i'm looking at, I think I would just 'mirror' the setup, and have it so

Jensen "orange" is connected to the 10uF cap
Jensen "red" goes to XLR pin 3 and phantom resistor
Jensen "brown" goes to XLR pin 2 and phantom resistor

Then Jensen "white," "yellow," and "black" go together to the electronic ground? I'm mostly unsure about these and whether they all go to ground at the same point.
Title: Re: Bo Hansen DI layout
Post by: spacecho on October 21, 2013, 02:11:05 AM
Hello All,

I'm planning on building a few of these using the Haufe Transformers, and I have a Lundahl 1530 Transformer sitting here so I would like to build one using this part. I checked the Data Sheets - it is 1:7 instead of 1:5, so apart for a greater level loss, would it be suitable? or better used in another project.

Upon looking at these data sheets, I found that the winding resistances are similar, but the 1530 is a a bit different.
www.lundahl.se/pdfs/datash/1530.pdf‎
www.lundahl.se/pdfs/datash/1538_8xl.pdf‎

I found that the pinout is slightly different - so to use it in the circuit, would I do this with the Lundahl1530:
-pins 1-4, and 2-3 (stay the same as lundahl 1538)
-pin "e" on the 1530 goes to Gnd (which is pin 8 on the 1538)
-pin 8 on the 1530 (+) goes to + (where pin 6 goes on the 1530)
-and pin 6 on the 1530 goes to where pin 5 goes on the 1538)

The datasheet mentions that I need to add a 1k terminating resistor (for 1:7 wiring) for the LL1530 transformer, where the LL1538 does not need one. Where would I put this resistor?


Thanks for your thoughts,
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on October 21, 2013, 04:27:45 PM
Spacecho,

Yes, you can use the Lundahl 1530 transformer in 7:1 configuration, but it have a bit more ratio, so you get some dB's more level loss compare with LL-1538.

Connect the 1530 as the 1:7 configuration according to the data sheet.
Note that the connections 1 to 4 is output to the XLR, and 5 to 8 shall be feed from the electronics.

If the DI-box is connectet to a regular balanced microphone input, you not need any termination resistor.

Read also my grounding instructions, that you find here: www.hansenaudio.se/techpage.htm

--Bo
Title: Re: Bo Hansen DI layout
Post by: tonycamp on October 21, 2013, 08:29:40 PM
wanted to thank you Bo, and post up some pics of my stereo DI, I used a PSU case from my IOaudio Mk47 donor mic build! also wanted to mention i lent it to a friend, he told me(quote), "i had no idea direct bass could sound this good", now i'm worried about getting it back lol
Title: Re: Bo Hansen DI layout
Post by: tonycamp on October 21, 2013, 08:30:33 PM
heres another
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on October 22, 2013, 12:32:00 AM
Hi everyone...

Still hoping for an answer to my question on this page about the reverse wiring of my transformer... Please help!  :-[
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on October 22, 2013, 02:17:39 PM
Jasonallenh,

Sorry, I missed your post.

Jensen JT-13K6-C  is a very good transformer for this purpose, perhaps somewhat impractical for our PC card, but with a little skill, it will fit.

Connect as follows:

Orange to 10 uF capacitor (amp out)
Brown to XLR pin-2
Red to XLR pin-3
Yellow, White, Black to the electronics 0V/ground (not chassis)

Note that the transformer case must be isolated from the DI-box chassis/housing.

--Bo
Title: Re: Bo Hansen DI layout
Post by: drAk on October 23, 2013, 03:18:18 PM
If I wanted to take the pad mod a little (okay, quite a lot) more to -40dB switchable, would I replace the 330K resistor with a 33.2K (105K for -30dB)? Would this drop the impedance too low?

Reason for this is to drop +4 line level down to mic level for FOH systems for live performance - multiple outs from audio interface feeding FOH via stage snake.

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on October 23, 2013, 04:47:40 PM
drAK,

When using the PAD circuit, the input have not any constant resistance/impedance, because it is added to a 2.2 Mohms resistor in series with the input.

But the lowest input resistance/impedance, even if you short the 330 kohms resistor to ground, (and it becomes infinite attenuation) will be 2.2 megohms as a minimum.

So you can change the 330 kohms resistor to a lower value for the desired loss, without having less than 2.2 megohms.

Btw,
The reason I'm not bothered to maintain the constant 1 Mohm input resistance/impedance when PAD is switched on, is because in this case is most often used a instruments with active outputs, where the impedance does not really matter anymore.

--Bo
Title: Re: Bo Hansen DI layout
Post by: drAk on October 24, 2013, 08:09:31 PM
Thanks for the clarification and education Bo. I'll proceed with my calculations to provide the 30 or 40 dB pad.

-drAk
Title: Re: Bo Hansen DI layout
Post by: monkeyxx on November 17, 2013, 01:58:23 AM
What would be the best way to wire up an extra input XLR for line input of, say, -20 dB, into the front end of the circuit?

I would want to get a balanced to unbalanced conversion with the lowest noise, is this possible?  All I know how to do is buy a second transformer for the job, or short one of the "hot" balanced signals to ground, but then you lose the balancing.  Is there a better way to do this?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on November 17, 2013, 02:18:34 PM
monkeyxx,

I'm not sure I understand exactly what you're after, but if it's just a balanced line input with 20 dB pad which will then end up in an unbalanced output.

If this is the case, then there is no benefit to using an active Phantom powered solution.

Then I would rather recommend a completely passive solution.

Use a transformer with ratio 1:5 to 1:10, and connect it backwards.
For example Lundahl LL1538, Haufe ST8456, OEP A262A3E has about 15 dB loss, and the input impedance are 5 kohms or higher, depending on what impedanse the output will drive.

To obtain an unbalanced output, connect the output winding out-of-phase end to ground.

--Bo

Title: Re: Bo Hansen DI layout
Post by: monkeyxx on November 19, 2013, 04:05:17 PM
Thanks Bo, I'm going to bang up some passive line 2 amp / preamp boxes with some affordable Edcor transformers, and use a DPDT to switch between a slightly padded XLR output, to run to mic pres, and a TS unbalanced output for pedals/amps using the same transformer and input.  I am actually pretty excited about this, and, it seems like a good product idea that's not really out there, other than on the Radial JDI Duplex, which does not really have a dedicated "reamp" output on the other hand, but does have the line to mic level capability.
Title: Re: Bo Hansen DI layout
Post by: seba on November 27, 2013, 07:36:14 AM
Hi, very good design.
I made two of them and then, I created an account on GroupDIY just to say : thank you
 ;)

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on November 27, 2013, 12:48:50 PM
Seba,

Glad to hear that you like my DI box design.

--Bo
Title: Re: Bo Hansen DI layout
Post by: GonzoConMojo on November 28, 2013, 04:46:25 PM
Hi there,

I tried to built my first DI, the Bo Hansen DI with the Lundahl LL 1538. It is finished, but upsetting me, because the level is quite low and the audio sounds distorted. I double checked everything, but couldn't find any mistake. Any guess what went wrong?

Thank you!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on December 01, 2013, 04:20:13 PM
GonzoConMojo,

During all the years that we discussed this DIY project, we have solved a lot of similar problems, there is usually a simple cause, but may take time to find.

You need to give us some more information about your DIY build.

Have you used our original PC card?

Are all components in the right place?

Have you carefully checked that you turned legs right on all transistors and diodes?

Have you measured the voltages if they match on the points I have indicated on my DIY page: www.hansenaudio.se/techpage.htm

Can you attach a good picture of the construction.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Esoterimix on December 02, 2013, 01:26:55 PM
don't think i have posted pictures yet... so, here is my rack job on Bo's DI... thanks for sharing Bo... as to having problems with distortion, mine can get a bit unruly from time to time but that is really only when the instrument itself has extremely hot outputs... if I turn the instrument down a little it turns into the juiciest bass Di sound I've ever heard besides some really expensive bass distortion/d.I. pedals Ive seen.... I can't wait to build another one.

I call it the "Hot Lunch." I've used it for live recordings,l and studio.recordings as well as a d.I. for live sound reinforcement, on bass and a couple analog syntjs and it is always very easy to get great tones from it....

Title: Re: Bo Hansen DI layout
Post by: GonzoConMojo on December 27, 2013, 01:06:25 PM
Hi there,

first of all, Bo, thank you very much for helping me. Sorry that I kept you waiting for so long, I've been quite busy recently. To everyone, I hope that all of you had a beautiful christmas this year.

Now for the project. I measured the voltages, what I indeed hadn't done before because my Multimeter was broken. The outcome is, that I noticed an amount of 43-45 Volts between Input Ground and LED positive instead of the suggested 24 Volts and again around 40 Volts between Input Ground and 10uF, while the voltage between Input Ground and Transistor Emittor was 20 Volts, instead of the suggested 12 Volts. Where do all the volts come from...?

Here are pictures of my build:

(http://www.dowtheband.de/dwl/BoDI1.JPG)
(http://www.dowtheband.de/dwl/BoDI2.JPG)

Thank you very much!

Cheers,
Bodo
Title: Re: Bo Hansen DI layout
Post by: monkeyxx on December 27, 2013, 01:30:01 PM
Where do all the volts come from...?

They come from magic beans inside the wall that shake, sweat, and get agitated when you plug them in.  This is how electricity is created.  Thomas Edison figured this out over 35 years ago.

Just kidding!

Basic troubleshooting practices:  Makes sure caps and diodes are installed right and not backwards, this matters.  They have a positive and a negative side.  Make sure the transistors are not backwards also.  Verify that every resistor is the right value in the right place.  Look very very closely at the solder side of the board, make sure there are no bridged traces, cold solder joints, or tiny fibers or contaminations creating shorts.  Go ahead and re-flow all of the solder joints to make sure none are "cold" this is called the "shotgun" method.

Cool looking build!  good luck.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on December 27, 2013, 03:51:31 PM
GonzoConMojo,

I think it looks like you have shifted the orange and red wire on the pc-card that goes to the XLR connector ?

The numbers on the PC card must match the number on the XLR connector pins.

Another thing, regarding hum and ground-loop.

I can not see from the picture if the phone jack metal thread is isolated from the chassis.
This is important to avoid ground-loops.

--Bo
Title: Re: Bo Hansen DI layout
Post by: GonzoConMojo on December 28, 2013, 01:40:22 PM
They come from magic beans inside the wall that shake, sweat, and get agitated when you plug them in.  This is how electricity is created.  Thomas Edison figured this out over 35 years ago.

monkeyxx,
thank you very much. I had a great laugh! Also thanks for all the advice and hints, that you gave me. I now succeeded in finding out what went wrong with my build: I had accidentally soldered two legs of one of the transistors together by half-eyed idiotism. Now I fixed the soldering-job and everything works and sounds fantastic! :)

Bo,
thank you, too, for your support. I didn't encounter humming resp. ground-loops yet, but if so I am going to keep your words in mind. You have created a really beatiful and so to speak 'musical' DI-Box back in 1975. Thank you very much for this piece of personal pleasure :)

Everyone, have a great New Year and speak to you soon.

Cheers,
Bodo
Title: Re: Bo Hansen DI layout
Post by: monkeyxx on December 28, 2013, 02:08:25 PM
Wooo!!  Glad to hear it.

Can't wait to build one myself!
Title: Re: Bo Hansen DI layout
Post by: baol on January 06, 2014, 04:52:26 AM
Hi, if I use the ll1538xl, must I change something in the schematic?
Thank you.
Andrea
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 06, 2014, 04:54:22 PM
Andrea,

No, the LL-1538-XL (extra lardge) is same transformer as LL-1538.
The only different is that the core is 45% bigger, so it can handle more clean level in the low frequency end.

--Bo
Title: Re: Bo Hansen DI layout
Post by: davide.bonetti on January 07, 2014, 09:23:32 AM
hello, I just registered on this forum as soon as I saw this project, I have been wanting to build some DI's in a while, because I have four transformers laying around from broken equipment. question: can I use OEP A262A2C instead of A262A3E... I don't think so, but maybe... is it possible to modify the circuit to make it work?
Title: Re: Bo Hansen DI layout
Post by: Kir_For_Pleasure on January 07, 2014, 12:25:57 PM
Tack Bo !

Grymt händig sak !
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 07, 2014, 02:51:27 PM
davide.bonetti,

No, sorry,  it is not usable for this application.

This is a 150 ohm to 600 ohm/1,2k (1:2+2) transformer, so it have to low ratio.


Kir_For_Pleasure,

Tack, hoppas du får mycket glädje av din DI-box.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Gearsix on January 11, 2014, 12:56:50 PM
Hello, does anyone know if it possible to use an old A262A1E instead of A262A3E?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 11, 2014, 04:27:27 PM
Gearsix,

No, sorry,  it is not usable for this application.

It's actually just A262A3E from OEP range that fit this DI box.

--Bo
Title: Re: Bo Hansen DI layout
Post by: bds2020 on January 11, 2014, 05:06:38 PM
Hi all - I'm new to building electronics and this looks like an excellent first build.  I thought it would be helpful to re-create the schematic on CircuitLab so I can try to understand what's going on as well as having a simulation of the circuit for test purposes.  I'm struggling with placing the inputs/outputs/power and am hoping someone here may have some suggestions. The link is here:
https://www.circuitlab.com/circuit/rhpsha/hansens-active-di-box/ (https://www.circuitlab.com/circuit/rhpsha/hansens-active-di-box/)

Thanks, Brian
Title: Re: Bo Hansen DI layout
Post by: Gearsix on January 12, 2014, 01:50:52 AM
Thank you Bo
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 12, 2014, 06:42:49 PM
Brain,

I never used any simulation software, so I do not know how much it understands of analog design that does not always follow the theoretical rules.

But if you must try to simulate the DI-box, you should remove the two phantom resistors, and instead connect +24 volts directly over 100 uF electrolyte.

You must also connect a 1 kohm termination resistor across the XLR pins 2 and 3 to be equal to the load that the DI-box will see from all phantom resistors and input impedance of pre-amp/mixing console.

You should also measure the output signal over this 1 Kohm resistor.

I do not know if the sowtware can simulate a microphone transformer connected backwards with a ratio of 5:1, which shall then have a primary impedance of 5 Kohms when the secondary side is loaded with approx. 1 Kohms.
And also take into account how the transformer is made, the size of the core etc.

This is a very interesting experiment, and I think there are others here on the forum who understand simulation sowtware much better than me, and have comments on my claims.

Best from
Bo
Title: Re: Bo Hansen DI layout
Post by: bds2020 on January 13, 2014, 03:57:21 PM
Bo,

Thanks for your comments.  I'm curious why you suggest removing the two phantom resistors (I think you're referring to the 6.8k resistors) and connecting the +24 volts directly over the 100 uF electrolyte.  I was thinking of inserting the 48v source b/t pin 2 and the first resistor.

Brian
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 13, 2014, 05:55:34 PM
Brian,

Sure, you can do this, because all four 6.8 kohm resistors (two in DI box and two in mike preamp) is theoretically connected in series/parallel, and then the end result is 6.8 kilohms.

But I do not know what the sowtware think about dc voltage connected unbalanced on the transformer secondary side.

Please note, the important thing about powering is that Di-box electronics internal "top voltage rail" is applied to a + 24 volt dc regulated voltage, and this voltage rail not draw more current than 3.5 mA.

And that you use a simulated transformer with right parameters, and terminate the secondary with 1 kohm.

For a simulation sowtware it is obviously very important to enter all the external circumstances that the simulated circuit will work with in the reality.

Especially as a DI box is connected between two other devices that actually affects the DI-box electronic enormously.
I.e. the guitar with the cable and the mixing console/preamplifier.

A circuit simulation that can not understand all the weird analog parameters, will probably have a very strange result, which tells you something completely different from what it is in reality.

Sorry, I'm very analog of me and very suspicious regarding simulation sowtware in analogous contexts.
But maybe I'm wrong, is there anyone else here on the forum who have experience related to this.

--Bo
Title: Re: Bo Hansen DI layout
Post by: byoung on January 14, 2014, 01:02:05 PM
I'm going to build a couple of these and was curious who has used hammond enclosures and which models work best with Lundahl or Haufe trnasformers?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 14, 2014, 02:01:36 PM
byoung,

A size that is practical and has plenty of room is Hammond 1590-TBK. (see my DIY page www.hansenaudio.se/techpage.htm)

The same size is also available from other manufacturers.

--Bo
Title: Re: Bo Hansen DI layout
Post by: bds2020 on January 15, 2014, 12:46:28 AM
Bo, thanks again for your comments on the CircuitLab experiment.  I asked for help on their forums, and one of the members replied with a cleaned up circuit and some good thoughts.  For those who are interested, here's the link to his re-designed circuit: https://www.circuitlab.com/circuit/5w3644/hansens-active-di-box-02/.   And here's the link to the forum thread: https://www.circuitlab.com/forums/audio-electronics/topic/s7b4up5a/bo-hansen-active-di/#comment_6233. 

I need to spend some time now trying to understand it.  It may be a fool's errand to try to simulate this device, but even if not successful, I"ll be less of a fool when done :)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 15, 2014, 02:40:53 PM
Brian,

This is very interesting , and especially when people on CircuitLab forum are involved in your project .

I am a little confused regarding the simulated receiving transformer.
It's ok to apply +48 volts on the primary center tap, but I prefer to apply the voltage via two 6.8 k , because this is the most common way to do it .

We know neither what is the impedance and the ratio of the receiving transformer , it looks very suspicious when there is a 100 ohm resistor termination on the secondary side.

The best way is to use a similar transformer at the sending end. (same as sitting in the DI-box)

The receiving transformer has its low impedance side facing the DI box's output, which is also low impedance .

The receiving transformer secondary becomes the high impedanse side in this case , and should be terminated according to the manufacturer recommendations, which is usually 10 times the secondary impedance .

In LL1538 case , usually 33 K give the best results , and also provides a relevant mirror impedance over to primary side.

It will be verry interesting to follow your simulation project.

You should compare your results with the technical data available on my DIY page www.hansenaudio.se/techpage.htm
These measurements are made "for real" with a normal connection and peripherals.

Best of luck.
--Bo
Title: Re: Bo Hansen DI layout
Post by: noiseattitude on January 16, 2014, 12:04:40 PM
Hi Guys,
this is my first post. I write from Italy, excuse me for my english.

I have a question about this project (the first for me):
Some days ago i ordered some OEP A262A3E, but Farnell, for a mistake, sended me OEP A262A2E  :( .
I think is not good for this DI-BOX project. Could you confirm it please?

Thanks for all !
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 16, 2014, 01:03:29 PM
noiseattitude,

No, sorry,  it is not usable for this application.

It's actually just A262A3E from OEP range that fit this DI box.

--Bo
Title: Re: Bo Hansen DI layout
Post by: noiseattitude on January 16, 2014, 01:29:52 PM
Thanks a lot Bo for your kind reply !
Title: Re: Bo Hansen DI layout
Post by: somorastik on January 27, 2014, 10:04:15 AM
Quote
Thanks for the reply Bo. Is this diagram correct?

Basically use DPDT SWITCH (ON-OFF-ON) wired so:

 toggle up     (SW1 CLOSED, SW2 OPEN) =    0dB
 toggle mid    (SW1 OPEN, SW2 OPEN)    = -10dB
 toggle down  (SW1 OPEN SW2 CLOSED) = -20dB

Have I got this correct?

Thanks for all your input, best wishes

Chris
« Last Edit: February 25, 2010, 12:22:54 PM by chrispbass »

Can someone help me make a schematic out of this? This is the only thing I could come up with:
(http://imagizer.imageshack.us/v2/800x600q90/838/0nss.jpg)

Toggle Up PAD1 PAD2 connected - 0dB
Toggle Mid PAD2 only- -10dB
Toggle Down PAD2 PAD3 connected - -20dB

I probably havent got it right....
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 27, 2014, 03:31:19 PM
somorastik,

No, your drawing is not correct.

I will describe it in the text instead of doing a sketch.

Use a simple toggle switch, 1 pole 3-position, on-off-on.

You have 3 pieces connecting pins on a line.

The one outer pin is connected to tip on the input jack, and on the same outer pins connect a resistor of 2.2 mohm in paralell with a capasitor at 18 pF over to the middle pin, also from the middle pin a connection to "+ input" ie 10k resistor on the PC card.

Finally, a resistor of 330 k connected from the other outer pin to ground (same ground as the input jack)

Now you have a PAD switch to 0 dB in one outer mode and -10 dB in the middle position and -20 dB in the other outer position.

--Bo
Title: Re: Bo Hansen DI layout
Post by: somorastik on January 28, 2014, 08:35:38 AM
Thank you so much Bo.

Now I think i got it!
(http://imagizer.imageshack.us/v2/800x600q90/703/jkxy.jpg)
Title: Re: Bo Hansen DI layout
Post by: Kir_For_Pleasure on February 18, 2014, 04:35:53 PM

Kir_For_Pleasure,

Tack, hoppas du får mycket glädje av din DI-box.

--Bo

bygger just nu på 3 till ;-)
Title: Re: Bo Hansen DI layout
Post by: Kir_For_Pleasure on February 20, 2014, 01:54:24 PM
Built the Di with oep transformer, after some reading i got interested to try LL1538XL
Got the LL today and mounted it very excited over how the result would be
Got very disappointed when i liked the oep better, more open and natural
1-0 to oep in my search for the perfect bass sound.
still got the recording if someone are interested to hear the diffrence ?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 20, 2014, 02:59:14 PM
Thomas,

If an audio transformer sounds good or bad in this case where the bass or guitars are involved, is of course a personal taste and preference.

The OEP A262A3E transformer have more "iron-character" compared with Lundahl LL1538 which is very neutral.

LL1538 without XL, has slightly higher bandwidth, but XL tolerate somewhat more level in the low end.

Lundahl's transformers are extremely neutral and clean, with no ringing or overshoot. (may sometimes be too good to be a transformer)

--Bo
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on March 11, 2014, 09:51:58 PM
Hopefully I can get some wonderful expert help on this  ;)

My DI has what appears to be ground hum- When I use the DI with my guitar, I hear a hum that goes away when I stop touching the strings. The same hum goes away If I touch the XLR pin 1. I measured my voltages per Bo's instructions and I got this-


BC560 Emitter voltage - 11.24V (Good!)

+ of 100uF capacitor - 24.24V (Good!)

Pin 2 to pin 1, and pin 3 to pin 1.... 36V (Higher than good??)

I am using the Jensen JT-13K6-C Transformer in reverse, and Bo confirmed with me in a previous post on this thread that I have connected it correctly. I am fairly certain I did something wrong in regard to the chassis ground scheme, but I want to make sure that my noise couldn't some way be related to my higher than expected voltage on my output XLR.

OTHER THINGS

Is the switched 1/4" connector for the INPUT or the amp OUTPUT?

Is it ok that I used a PLASTIC Neutrik XLR?

Thanks

=jh=

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 12, 2014, 05:19:27 PM
Jasonallenh,

The voltage between XLR pin 1 to pin 2, and pin 1 to pin 3 should be around 36 volts, so this is quite ok.

You say "ground hum" and that it disappears when you touch in the strings or when touching the XLR pin 1.

I think you mean "buzz", which is also common for a guitar / bass to pick up from various electrical disturbances on the stage or the room you are in.

How do you use the DI-box?
Guitar to DI box input and XLR out to a pre-amp, or do you have anything else connected to the DI-box, as an amplifier or mains connected effect pedal.


Have you installed a DI-box electronics in a metal box?

Please show a picture of how your DI box is built.

--Bo
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on March 12, 2014, 06:50:10 PM
BO! Thanks for responding.

I am using the DI with the XLR output connected to a recording interface with a guitar plugged into the Input. The guitar is an Epiphone Wildkat. The 1/4" output is not connected to anything.

I connected my Jensen transformer properly (double and triple checked per your instructions) and I have both XLR pin 1 and the chassis connected to the correct point (the 100 Ohm Resistor)

As my transformer does not fit the bboard, I have isolated it from the chassis by using PLASTIC cable mounts and Zip-ties. I don't currently have a picture, but I know for sure that there is about 1/8 inch of plastic separating the transformer from the chassis. The only point at which I have strayed from the grounding scheme is that I have used a plastic XLR connector. I'm using the plastic 1/4" connectors (the Rean models you've specified).

I don't currently have a picture to upload, but I am going to try and bring in a friend with a decent keyboard that I can test it with, because like you said, I may just be hearing normal guitar noise.
Title: Re: Bo Hansen DI layout
Post by: somorastik on March 13, 2014, 09:36:56 AM
Hi Bo!

I am using an old transformer from TESLA (socialist electronic company) it is 1:4 but the problem is probably that the primary is about 40 Ohm (measured with digital multi meter) and secondary is 10 Ohm. As oposed to Lundhall which is 880 Ohm to 44 Ohm.

For now it works good, but on 24V it eats more than 10 mA, at 9 V it is about 3,78 mA.

What should I modify to adjust the current? What would you recommend?

The transformers I used are high quality, so I want to keep them in the layout.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 13, 2014, 11:16:44 AM
Somorastik,

If the DI-box electronics is working ok, it shall only draw 3,5 ma from 24 volt supply.
So I think you have some problem with your construction.

If you not feed the voltage supply from phantom power, you shall connect a regulated 24 v dc voltage in this point there the two 6,8 k resistors is connected together.
(dissconnect the two resistors if you not use phantom power)

--Bo
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on March 14, 2014, 01:25:18 AM
So,

I tested my DIs (two in the same box) and I am getting SOME noise, not noticeable unless I really crank the gain. It is quite obviously more noisy when I used electric guitars.

Acoustic guitar plugged directly into the box, and then the box is connected directly to my recording interface (Scarlett 18i20). I did this with a guitar amp connected to the amp output... Not noisy, but a faint little bit. You start to hear it clearly once the gain is pegged, but that's the case with everything.

Electric guitar connected the same way was definitely noisier.

I'll be getting my hands on a keyboard sometime in the next week to get the guitar pickups out of the signal chain =}
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 15, 2014, 08:47:14 AM
Jasonallenh,

Can I see a picture from the DI-box inside.

Do you have clean phantom powering from your sound card ?
(have you try with a other pre amp)

Maybee you use a noisy brand/type of transistors.

If you not have anything plugged on the DI-box input, and the jack is shorted to ground, do you still have noise/buzz ?

--Bo
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on March 15, 2014, 07:24:08 PM
If you not have anything plugged on the DI-box input, and the jack is shorted to ground, do you still have noise/buzz ?

--Bo

It is absolutely silent when nothing is connected to the input jack. I think I may have corrected my problem. I plan to test it with the test tone on my cable tester. I feel like that will tell me if it is a grounding issue once and for all. (Don't know why I didn't think of this before  ;D).

PICTURES PICTURES PICTURES! I keep forgetting to do that, so sorry.
Title: Re: Bo Hansen DI layout
Post by: somorastik on March 18, 2014, 08:02:26 AM
Bo, thank you so much for the reply. You are the best. I managed to get the DI working great. As you noted REMOVE the 6k8 resistors when testing with an external supply!!! I guess when one does not do this the core gets saturated and the current drain raises since the transistors need to work in a different operating point?

Anyway here are the photos. My board contains the heart and soul- the Bo Hansed DI, a throughput jack and an attenuator switch for 0, -10 dB, -20 dB. I am using an old TESLA transformer 5AN650 55.

 8)

Thanks Bo!

(http://i1052.photobucket.com/albums/s448/shrek311/2014-03-18121122.jpg)
(http://i1052.photobucket.com/albums/s448/shrek311/2014-03-18121110.jpg)
Title: Re: Bo Hansen DI layout
Post by: stevekwok on June 23, 2014, 03:00:39 AM
I am so exciting to start making a DI by my own. I pick the OEP transformer but I found there is a metal enclosure which is sold separately. Is this metal cast necessary?

Thanks!

OEP A262A3E  AUDIO FREQUENCY TRANSFORMER
(http://cpc.farnell.com/productimages/farnell/promo/1689033-40.jpg)

OEP A262CAN  TRANSFORMER ENCLOSURE
(http://uk.farnell.com/productimages/farnell/standard/42416187.jpg)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 23, 2014, 05:02:54 AM
Stevekwok,

If you use a good metal box as DI-box case, you not need the mu-metal can for the transformer.

--Bo
Title: Re: Bo Hansen DI layout
Post by: stevekwok on June 25, 2014, 09:31:47 AM
Thanks Mr. Hansen,

How can I test the unit before I plug it in the mixer so I won't blow up the would system?

Again, thanks for your great work!

Regards,
Steve
Title: Re: Bo Hansen DI layout
Post by: RuudNL on June 25, 2014, 10:12:33 AM
Not very much can go wrong... (Even if the circuit would be a complete short circuit, the maximum load would be 2 x 6.8 K resistors, causing a current of 3.5 mA in each 'leg'!)
What you could do, is leave the two 6.8 K resistors out of the circuit and connect a 24 V. power supply to the 100 uF capacitor.
If you don't get smoke, you can safely connect the secundary side of the transformer to a mixer and see if you get an audio signal.
Since the DI box is now externally powered, it does not draw any current from the mixer input.
If everything passes this test, add the two 6.8 K. resistors and you are done!
Title: Re: Bo Hansen DI layout
Post by: alec1511900 on July 06, 2014, 04:29:17 PM
I have just finished the DI but don't seem to be able to get any sound at all when I tested it.  I have done the 12 and 24 volts tests and everything seems to be fine as well as the 36 volts test for the xlr socket and no problems there also.  The transistors also seem fine and connections to the input jack seem to have a good connection.  Does anyone have any ideas or know any other tests that I can try to get to the bottom of the problem?
Thanks
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on July 14, 2014, 12:16:45 PM
alec1511900,

If you have 24 v over the 100 uF electrolytic and also approx. 12 volt om the both transistors emitters, the electronic must be in function and work ok.

Maybe you have problem with the output transformer connections ?

Try to check this:
Conect the DI-box to a phantom powered mike-input as normal, and connect the unbalanced telejack output to a guitar amp input.
If you have sound in this case, it is some wrong with the transformer.

--Bo
Title: Re: Bo Hansen DI layout
Post by: alec1511900 on July 19, 2014, 05:38:27 AM
Thanks for the reply Bo, I thought it could be the transformer so thanks for the confirmation.  I'll do some more tests when I get a chance.
Title: Re: Bo Hansen DI layout
Post by: flood on August 12, 2014, 02:18:56 AM
Hey there Bo! Thanks a lot for your contribution by making the DI schematic public, it sounds great even with a Vigortronix transformer, for both guitar and bass.

As a way of apology to a friend (I dropped his guitar, scratching it up pretty bad  :-[ ), I am building him a load box (30 ohm 200W, made from 4x 30 ohm 50W resistors in series parallel) and the DI in one enclosure. I've prototyped the circuit without a chassis, it sounds excellent - with the amp driven all the way up for maximum saturation and an impulse response thrown on top of it. great for silent recording.

now that i'm looking at different ways of housing the circuit, I'm a bit confused as to how I should go about it - although it was primarily meant to be a simple load box with an output, i figured it would be better to throw a balanced output with the ground lifted, just in case of any voltage problems between amp and interface.

my problem: i'm just a little confused about how the grounds between the two circuits should work. i drew up the following circuit - does this look OK? all the jacks are isolated from the chassis using plastic washers. i'd be really grateful if somebody could verify the correctness of this circuit, or tell me if there are any foreseeable problems. thank you and best regards from bombay!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 12, 2014, 05:08:28 AM
flood,

You can of course combine the ground systems for both the dummy load circuit and the DI box electronics and place my ground loop suppressor in another place.

But I will not confuse it for you and other readers who may be interested in a similar idea, I suggest that the ground system is divided into two units.

The best way is to let the dummy load circuit belong to the guitar/bass amp ground systems, and the DI box chassis ground belong to the mixing consle ground system,
the same ground system idea that DI box has in the original, so it can isolate mains connected devices that are connected to the DI-box input or un-balanced output from the mixing console or preamp ground system.

--Bo

Title: Re: Bo Hansen DI layout
Post by: flood on August 12, 2014, 05:34:18 AM

The best way is to let the dummy load circuit belong to the guitar/bass amp ground systems, and the DI box chassis ground belong to the mixing consle ground system,
the same ground system idea that DI box has in the original, so it can isolate mains connected devices that are connected to the DI-box input or un-balanced output from the mixing console or preamp ground system.

--Bo

Thank you for your quick reply Bo! Just to make sure I understand your instructions correctly:

1. The chassis is connected using a screw lug from the chassis to Pin 1 of the XLR jack. (I'll call this one GND1)
2. The ground loop suppressor circuit is connected at one end to Pin 1 (GND1) and at the other end to the DI box circuit ground (GND2).
3. This would mean that GND2 will have to share the same ground as the load box when the two are connected, and my drawing is ok?

I'm just concerned about preventing any accidental damage to his sound card or amplifier - both are quite expensive. Of course, I will be testing it extensively on my own setup before giving it to him. I also just realized that I did not show the DI circuit as being connected to circuit ground in my drawing, apologies for that.

Thank you and best regards!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 12, 2014, 06:43:16 AM
flood,

Yes, your description is right.

Use a separate metal box to contain DI box electronics the same way as normal.
Install the dummy load components separately outside DI box electronics.
It is important to not use the DI box the chassis as dummy load ground connection.

Mixing console, preamp or soundcard is protected from short circuit or other fault, as long as the transformer balanced output is used, and the XLR pin 1 is ground and nothing else.

--Bo
Title: Re: Bo Hansen DI layout
Post by: gforsythe on September 11, 2014, 01:10:15 PM
Awesome thread here!

So I am a total noob with DIY projects and am using this awesome DI as my starting point. I feel pretty confident moving forward for putting it together, but ran into one question that is super basic but something I was curious about. I got my Hansen DI PCB from PCB grinder.com and have been following their instructions, and there isn't anything detailing the wiring step, just a photo. While researching Bo Hansen's website about grounding it says "[it] shall only be grounded on the XLR output connector pin 1, and also connected to a solder tag fixed in one of the XLR fasten screws." The photo on PCB grinders assembly instructions (though low resolution) clearly shows the ground terminal wired to the chassis, as opposed to the instructions on Bo's site. Is this PCB different in any way from the original design? Has anyone else acquired their PCB from PCB grinder, and if so what was their grounding wiring like? Any information would be hugely helpful so I can start this build. Thanks!!!!

Glenn
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on September 15, 2014, 07:33:48 PM
Hey guys, I'm working on a smallllll PCB to use when a transformer must be wired off the board, as is the case with my jensen jt-13k6-c. It saves you quite a bit of space as it's only about 1.5" x 2.5"

https://www.dropbox.com/s/r93oktrj62eb9bj/BHDI%20Rough%20Draft.jpg?dl=0

Does this look correct? I've left six pads to use in the center for transformer connections. 

Thanks for your patience!  ;D
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 22, 2014, 01:06:11 PM
Glenn,

I myself have been involved with the development of this PC-layout, and therefore know that it is correct.

The grounding is simple, just follow the text on the PC board connectors. XLR pin 1 to pin 1 and chassis to the metal case, a proper screw, such as the one screw that holds the XLR connector.

Look at the photos here on the forum, there are lots of clear photos of peoples builds that are properly made, and questions and answers about the grounding in plenty through the years.

Good luck with your DIY.

--Bo

Title: Ultra Small Bo Hansen DI
Post by: jasonallenh on September 22, 2014, 02:25:01 PM
Hi All,

I originally posted this in the main BHDI thread, but I figure it should land  here.

I designed a PCB for use with non-standard transformers that HAVE to be wired off the board (Jensen Trafo for example).  It's as small as possible (about 2.5" x1.5") and allows for you to fit the whole DI in a BB sized stomp-box.  I'd like some advice on any improvements/suggestions that anyone may have.

The basic design is here-

https://www.dropbox.com/s/r93oktrj62eb9bj/BHDI%20Rough%20Draft.jpg?dl=0

There are six pads to the immediate right of the BC550C where you would connect your transformer. Remember: the pads aren't meant to accommodate a PCB-mount transformer! This means you must find a way to isolate the transformer case from your enclosure.

What do you guys think!?
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on September 23, 2014, 07:49:20 PM
Bo-

Hey guys, I'm working on a smallllll PCB to use when a transformer must be wired off the board, as is the case with my jensen jt-13k6-c. It saves you quite a bit of space as it's only about 1.5" x 2.5"

https://www.dropbox.com/s/r93oktrj62eb9bj/BHDI%20Rough%20Draft.jpg?dl=0

Does this look correct? I've left six pads to use in the center for transformer connections. 

Thanks for your patience!  ;D
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on September 25, 2014, 03:14:44 AM
Jasonallenh,

It seems to be connected right, but the LED is connected wrong. Compare with the original PC card, so you can see how it should be connected.

--Bo
Title: Re: Bo Hansen DI layout
Post by: jasonallenh on October 01, 2014, 10:05:35 PM
Shouldn't I have LED + to the 6.8k phantom resistor and LED - to the + of the electrolytic? I'm not seeing what I missed!  :-\
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on October 03, 2014, 12:36:58 PM
jasonallenh,

The LED shall be connected in series with the voltage rail.
Cut up and insert the LED between the junction of the two 6,8 k resistors and the 100 uF electrolytic capasitor.
You can see the way to do it on the orginal PCB layout.

--Bo
Title: Re: Ultra Small Bo Hansen DI
Post by: Bo Hansen on October 03, 2014, 12:47:17 PM
jasonallenh,

Much better you post everything about my DI-box on the main  thread in the "Lab section" , because mostly of the DI-DIY people are there and discuss my DI.

--Bo
Title: Re: Bo Hansen DI layout
Post by: jensenmann on October 05, 2014, 02:47:53 PM
Since my other Bo Hansen DIs never returned back to me I had to make a few new ones.
Thanks for this great project, Bo!!!
Title: Re: Bo Hansen DI layout
Post by: monkeyxx on October 05, 2014, 03:08:44 PM
wow those look great!  8)
Title: Re: Ultra Small Bo Hansen DI
Post by: abbey road d enfer on October 06, 2014, 03:58:23 AM
jasonallenh,

Much better you post everything about my DI-box on the main  thread in the "Lab section" , because mostly of the DI-DIY people are there and discuss my DI.

--Bo
I agree with you, this thread should be merged with the main one, but which one?  ;)
There are about 5 different BHDI threads i the Lab...
Title: Re: Ultra Small Bo Hansen DI
Post by: Bo Hansen on October 06, 2014, 04:15:35 AM
abbey road,

This topic/thread with near 100.000 visits.
http://groupdiy.com/index.php?topic=36569.0

--Bo
Title: Re: Bo Hansen DI layout
Post by: Markus_Krippner on October 20, 2014, 02:08:52 AM
Hi :-)

Has anyone ever tried "CDIL" branded transistors for the Bo Hansen DI ?

https://cdn-reichelt.de/documents/datenblatt/A200/BC550C.PDF

Are these good enough ?
Or is it better to look for "wellknown" brands ?

...markus :-)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on November 02, 2014, 11:44:45 AM
Markus,

I think they can be ok, try the input BC550C transistor and compare with a good orginal brand as Motorola, National, Philips, Telefunken,  SGS/Ates, if you not can here more noise with the "CDIL" transistor, it can be ok for this project.
Test with chorted input.
--Bo--
Title: Re: Bo Hansen DI layout
Post by: 12afael on November 02, 2014, 09:47:44 PM
Hey Jens do you hear any difference between Haufe and Oep? which one do you prefer?
Title: Re: Bo Hansen DI layout
Post by: jensenmann on November 03, 2014, 06:19:10 AM
Sorry, I didn´t do any comparison. If you desperately need to know if there´s a difference then let me know. I´ll try to make files for you.
Title: Re: Bo Hansen DI layout
Post by: 12afael on November 03, 2014, 11:08:36 AM
No problem Jens it was just curiosity.
Title: Re: Bo Hansen DI layout
Post by: Markus_Krippner on November 03, 2014, 01:12:38 PM
I'd be interested in sound differences....cause i'm thinking about building a Bo Hansen DI with 4-6 switchable transformers.

1 Switch Position "Clean Expensive Highend", (Lundahl?...Haufe?...or both if theres a difference?)
1 Switch Position "Cheap 5 Dollars", (just for A/B comparison for people without golden ears ;-)
and 2-4 Positions with a "Character".

I'd be interested what to choose for the Character positions.

...markus :-)
Title: Re: Bo Hansen DI layout
Post by: monkeyxx on November 03, 2014, 01:14:26 PM
Don't forget about the Lundahl either, I've heard said that it's very good in Bo's DI... I might try one
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on November 26, 2014, 02:29:29 PM
Amazing, we have now passed  100,000 views in this thread.

Many thanks for yours enormous interest in my active DI box, hope many of you become satisfied with your DIY builds.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Studio Mollan on December 12, 2014, 08:21:49 PM
Hi,
I have built a couple of these and been using them regularly the past years. Today I tried them with a piezo contact microphone on a piano and got a huge 50hz ground loop. I used two and they both have got the same issue. I opened them up and they appear to be built according to spec. any ideas?
I'm using a white LED, case grounded only from the ground pad on the circuit board. Plastic trs jacks. The piezos are mounted on wood.
Title: Re: Bo Hansen DI layout
Post by: monkeyxx on December 12, 2014, 08:31:50 PM
Try a ground lift.  Can really help in some situations.
Title: Re: Bo Hansen DI layout
Post by: Studio Mollan on December 13, 2014, 08:16:42 AM
Try a ground lift.  Can really help in some situations.

But not in this circuit I think? The ground is also a 0v for the 48v power. I read early in this thread where Bo advised against it.
/
Emil
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on December 14, 2014, 08:26:41 PM
Studio Mollan,

You do not need a ground lift switch in this construction, because it has a "ground loop suppressor" that works well under normal ground loop problem situations.

 In addition, the phantom powering systems will be very poor with a ground lift switch, because the negative side must find their way through the power system grounding in order to reach the DI-box.

I think your problem is that your piezo microphones or its connections are not properly shielded.

 I guess the hum or buzz disappears when you pull out the input connector from the DI-boxes?

 I assume you feed the DI boxes with a stable and clean 48 volt dc voltage.

Of course, if you have hum / buzz problems even when you do not have anything connected to the inputs, then please get in touch with me.

If so, I want to see how the DI-box looks like on the inside, and know exactly what type of external equipment you have connected to the DI-box in / out connectors.

 A small comment about the LEDs.

I have repeatedly pointed out that you must use a red LED, to get the best headrom and clipping behavior.
 So, do NOT use yellow, orange, green, blue, white or flashing types.
 The reason is that the red LED has the smallest voltage drop compare with the others.

--Bo

--Bo
Title: Re: Bo Hansen DI layout
Post by: philipNL on January 16, 2015, 10:14:48 AM
Does anyone have the assembly guide?
https://pcbgrinder.com/download/BODI28/BODI28-assembly.pdf

Its offline :(
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 17, 2015, 06:51:28 PM
philipNL,

BODI128 was a version of my "Bo Hansen Active DI Box 1975" that PCB-Grinder made on their own initiative , recently published on their web page, but which I thought not coresbond with our DIY projects in this topic/thread .

Therefore, I and PCB-Grinder desided that their version would be removed and the old original card will be restarted by me or any other company that takes over the production and sale of original PCB.
We are working on this right now.

Regarding the old ORIGINAL version's description and advice, please visit my DIY page www.hansenaudio.se/techpage.htm

--Bo
Title: Re: Bo Hansen DI layout
Post by: philipNL on January 18, 2015, 09:30:21 AM
Thanks Bo!
Any idea of when this new original pcb will be for sale?

Thanks!
Title: Re: Bo Hansen DI layout
Post by: Humner on January 22, 2015, 10:22:11 PM
nevermind - asking silly questions, just had a look a closer look as to what this is.
Title: Re: Bo Hansen DI layout
Post by: warpie on January 24, 2015, 09:18:38 AM
After spending a couple of years using this DI I must say I really like it.

However, I have the following "problem/question".

When I record I use pretty much all my mic inputs for mics. I do have spare line inputs in my interface so I was wondering if there's any modification that can be done in order to use this DI with line level as opposed to mic level. Of course the DI would have to be powered by a separate/external Vdc, I understand this  :)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 25, 2015, 01:33:14 PM
philipNL,
We can not find "Garber files" to the original PC layout, so we have to redo the layout again, and Soeren_DK doing this right now.
 It will take some months before the PC cards are available for delivery again.


Humner,
Sorry, I do not understand your question, do you mean what this DI-box should be used for ?

Warpie,
If you use a 1:1, 5k or 10k to 5k or 10k transformer and run the DI-box electronics with dc-regulated 24 volt that you insert after the two 6k8  resistors and ground, you can get near 1 volt out if you use  high output pickups on the guitar/bass.

Sometimes, there are typically 10 dB gain make up on line inputs, so maybe it will work fairly well.

--Bo
Title: Re: Bo Hansen DI layout
Post by: azure skies on January 27, 2015, 02:16:03 PM
I noticed on the OEP datasheet in the notes they say Do not pass DC through the windings

Is the phantom power typically balanced well enough to not pass any appreciable current through the windings from pin 2 to 3 (or 3 to 2)?

Also, I wanted any advice anyone could give on adding a mute. Bo mentioned having a switch in parallel with the output of the 10uF and ground, with a 100k resistor fixed to ground. Are there any other pointers to making the circuit resilient to "pops" when muting? This is to help protect the PA when connecting/disconnecting acoustic guitars to the DI, typically resulting in very loud pops coming through the system.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 27, 2015, 09:14:23 PM
azure skies,

If you connect the Phantom powered microphone cable right, there are no dc current between pin 2 and 3.
The Phantom system feed same +48 volt to both pin 2 and 3 split from two resistors.
The minus/ground 48 volt is only feed to pin 1, and this is total isolated from transformer windings.

Yes you can connect a single pole switch after the 10 uF capacitor to ground, so the output signal is shorted to ground in mute mode.
In this case you not need a extra  100K resistor.

--Bo
Title: Re: Bo Hansen DI layout
Post by: azure skies on January 28, 2015, 08:21:26 AM
Thanks for the feedback, Bo.

One other question....

I want to use two of these in parallel for stereo operation. I would like to use an actual stereo plug (3.5mm) as opposed to two mono plugs for left and right. What is the best way to wire for this configuration? Here is what I would gather:

The stereo plug is isolated from the chassis. The left signal goes to one board, the right signal goes to the other board. The sleeve terminal has two wires, one going to the ground of each board. Both XLRs are connected to its respective board as usual, with a chassis connection to each pin 1. Does this sound right?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 28, 2015, 11:41:13 AM
azure skies,

Yes, absolute right, this connections style will be fine.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Whoops on January 30, 2015, 08:47:41 PM
philipNL,

BODI128 was a version of my "Bo Hansen Active DI Box 1975" that PCB-Grinder made on their own initiative , recently published on their web page, but which I thought not coresbond with our DIY projects in this topic/thread .

Therefore, I and PCB-Grinder desided that their version would be removed and the old original card will be restarted by me or any other company that takes over the production and sale of original PCB.
We are working on this right now.

Regarding the old ORIGINAL version's description and advice, please visit my DIY page www.hansenaudio.se/techpage.htm

--Bo

Hello Bo,
Im sorry I really didn't understand what was the problem with the BODI128,
you mean the BODI128 was a version based on your DI but was not as good as your original layout?

Or that the BODI128 was being sold without your approval, and now it will be sol by you or someone you approve?

Is that I didn't understand what you meant by "which I thought not coresbond with our DIY projects in this topic/thread ",
I have some BODI128 and if there's any problem with the circuit or if the original circuit is different and better, I would prefer to do this projects with your boards.

Thank you
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 31, 2015, 10:01:36 AM
philipNL,
and all of you who are wondering about the same thing.

Here is the story in short, why our original PCBs were removed from the PCB-Grinder's product line and instead replaced by a new PCB and kit, and now also been removed from their products.

From the beginning, the project started with the "original PCB layout" that two guys from Denmark, Soeren-DK and Luny Tune wanted to make a circuit board that suited my DI-box design, and I helped them with this.

Gustav, another Danish guy took on the task of producing and selling this board for a cheap price, and so far so good.

To day, Gustav run his business PCB-Grinder, and have decided to no longer manufacture and sell our original circuit board according to the original PCB layout that corresponds exactly to all this we have discussed in this thread here on the forum, which is now over 100,000 people read and taken note of.

PCB-Grinder decided instead to make its own circuit boards and a complete kit based on my DI-box design.
They also decided to use their choice of transformer and remove the option of the three of me approved transformers which perfect fit the original circuit board.
They have also made all connectors PCB mounted/placed, and this makes it harder to use various types of metal boxes, becauce the new circuit board is adapted best for their own metal box.

I and Gustav have discuss my views on his own initiative and version of my DI-box design, but we can unfortunately not agree and get along.
We decided instead that he will remove everything associated with my DI-box design from his product sortimen, and he will instead makes a completely new own DI-box electronics that does not remind of my design.

I am now developing new original circuit boards, and these will be sold by me or any other chosen person/company who will handle this.
I will return with more information as soon as possible.

Those of you who bought the PCB-Grinder BODI128 pc-cards or kit, and have problems, may contact PCB-Grinder directly for support, I can unfortunately not help you with this, because I have not been involved in their design in any way at all.
(they have done so on their own initiative without my knowledge or to ask me)

Regarding all of you who want to build "Bo Hansen Active DI-Box 1975" with the original circuit board or otherwise, are very welcome  with questions and more, here at this forum thread, and I will help you as best I can, as I have now done in 5 years when this thread existed.

I will also thank Gustav for all those years, he produced and sold our original circuit board, he did a great job and effort.
But unfortunately it was not in sufficient quantity to be profitable, probably this was the reason that he did our DI-box projects in his own way.

Best from
Bo
Title: Re: Bo Hansen DI layout
Post by: philipNL on January 31, 2015, 10:46:09 AM
Thank you for explaining!!  :) :) :)
Title: Re: Bo Hansen DI layout
Post by: warpie on February 01, 2015, 06:46:50 AM
Warpie,
If you use a 1:1, 5k or 10k to 5k or 10k transformer and run the DI-box electronics with dc-regulated 24 volt that you insert after the two 6k8  resistors and ground, you can get near 1 volt out if you use  high output pickups on the guitar/bass.

Sometimes, there are typically 10 dB gain make up on line inputs, so maybe it will work fairly well.

--Bo

Thank you Bo  :)
Title: Re: Bo Hansen DI layout
Post by: Humner on February 02, 2015, 07:13:50 PM
Thank you so much Bo.

Now I think i got it!
(http://imagizer.imageshack.us/v2/800x600q90/703/jkxy.jpg)

Can someone confirm this is correct for the PAD switch?

I think I will go the self etch route - its hard to find the original PCB's!

I have recreated the self etch layout in my own PCB software to make my own modifications(I'm only using the OEP transformer)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 02, 2015, 07:59:15 PM
Humner,

Yes, you have get it right. (if the switch is a 3 position on-off-on)

BTW, are you sure you need a PAD on the DI-box input ??

Note, you have use the older schematic, it is better if you change R3 and R4 to 100 K, and C3 to 10 uF.

If you read my instruction on my tech-page www.hansenaudio.se/techpage.htm ,you can find the right tips and build instructions, there is everything you need.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Humner on February 02, 2015, 09:00:18 PM
Hi Bo,

Thanks for your response. You are right, pad on the input isn't completely necessary, I think its more of something to have just in case.  But now I'm thinking to leave it out all together.

The schematic shown is from another member who posted previously. I used it as it was a clear reference to the PAD mod.
Title: Re: Bo Hansen DI layout
Post by: Whoops on February 02, 2015, 09:20:24 PM
Thanks for the feedback, Bo.

One other question....

I want to use two of these in parallel for stereo operation. I would like to use an actual stereo plug (3.5mm) as opposed to two mono plugs for left and right. What is the best way to wire for this configuration? Here is what I would gather:

The stereo plug is isolated from the chassis. The left signal goes to one board, the right signal goes to the other board. The sleeve terminal has two wires, one going to the ground of each board. Both XLRs are connected to its respective board as usual, with a chassis connection to each pin 1. Does this sound right?

I think it's as simple as that!
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 11, 2015, 03:40:02 PM
I've finished building the Bo Hansen DI, but It has some faults. The output is very low. I've to turn the preamp up to 75 db to hear something.
The led does work (3mm red led)
And when I unplug the jack in the input I hear a lot of noise.

Hear the sample:
http://picosong.com/Lt8Y

You hear me ticking on the chassis after i unplug the jack cable.

Im using the OEP transformer.

Does anyone know or can see on my pictures what the problem might be?
THANKS!

Im a first time DIY'er.

(http://i60.tinypic.com/x58idl.jpg)
(http://i60.tinypic.com/2cmup0g.jpg)
(http://i61.tinypic.com/2i0d8vp.jpg)

Title: Re: Bo Hansen DI layout
Post by: RuudNL on February 11, 2015, 04:55:50 PM
I prefer to use a jack that shorts the input when nothing is plugged in.
What you hear is an 'open input'. You probably did not have the box closed when you made the recording. (=Hum)
Or you did not connect the metal of the enclosure to pin 1 of the XLR connector.
The level (-75 dB) is a bit strange, although I don't hear any distortion or other problems.
You could measure the voltages on the collector and emitter of the transistors and let us know, that will give an indication about the correctness of the circuit.
The output level is determined by the output level of the pickup coils in your guitar, and the step-down ratio of the OEP transformer.
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 12, 2015, 02:46:24 AM
Hi Ruud,

Thanks for your reply and nice to see you here. You repaired my Neumann u87ai which my dad brought to you in Fryslan :)

I didn't have the box closed indeed and I didn't connect the metal to pin 1 of the XLR connector.
I did connect a wire from the pcb where it says 'chassis' to a screw in the metal enclosure. But I didn't do anything with the xlr pin 1.

So If i'm not mistaken. I need to connect two wires from the "chassic" on the pcb board. One to the XLR connector pin 1 and one to a screw in the metal enclosure. (which i already have).

Is that correct?

Thanks for your help :)
Title: Re: Bo Hansen DI layout
Post by: Gustav on February 12, 2015, 02:53:44 AM

Gustav, another Danish guy took on the task of producing and selling this board for a cheap price, and so far so good.


Just to clarify, since I am getting mails about this.

I get permission to sell the projects when I make boards for others, so I saw no reason to involve Bo when doing my own take on this, in my view,  generic design.

After being contacted by Bo, I realised I never talked to him direct and only Søren/Luny when starting the production, I therefore respected Bo's wish to discontinue the new board rather than continue a project managed by a third party.

There were clear reasons for my decision to evolve the project, and for the same reasons, I am currently working on my own board. There will be no reference to Bo's name or the 1975 dated project on this, but I will not restrict myself from using protection diodes or filters or other generic design tools, just because they were used in Bo's design.

So no, I no longer sell the BO DI board, and dont bother mailing me to ask if I still have some in the drawers. I will leave this to someone else and focus on a new design going forward.

All the best :)

Gustav
Title: Re: Bo Hansen DI layout
Post by: RuudNL on February 12, 2015, 03:18:00 AM
@philipNL: if you take a closer look at the PCB, you will find that the point 'Chassis' is connected to pin 1 of the XLR connector.
So in fact it doesn't matter, the connection is the same!
Closing the metal box will make a big difference in hum, because now (with the box open), the unshielded wires act as an  'antenna' and will pick up all electric fields in the neighbourhood of the DI. Especially because the input impedance is very high. (1 Meg.)
I suppose the hum and noise will stop at the moment you short the input.
For this reason I use jacks with a contact that closes when you pull the plug, so that the input is shorted to ground.
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 12, 2015, 04:19:08 AM
Hi Ruud,

Thanks. I will try that.

Do you have an example of a jack that has a contact that closes?

Thanks!
Title: Re: Bo Hansen DI layout
Post by: RuudNL on February 12, 2015, 04:50:27 AM
1/4" Jack with break switch, like the ones produced by Cliff  (http://www.cliffuk.co.uk/products/jacksockets/s2.htm)(CL1160A)  or Neutrik (http://www.neutrik.com/en/audio/plugs-and-jacks/m-series/nmj4hc-s)
The good news is: they are cheap (http://www.eoo-bv.nl/index.php?_a=viewProd&productId=14158)!
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 12, 2015, 09:05:57 AM
Thanks.

The DI is working but still very low output.
I recorded a sample, Bo Hansen DI vs. Apogee Duet DI.
The Bo Hansen needs +75db and the Duet only +13db.

Also quiet a sound difference. Is the Bo Hansen supposed to sound like this? (played with stratocaster).

http://picosong.com/LDdW

Thanks :) :)
Title: Re: Bo Hansen DI layout
Post by: RuudNL on February 12, 2015, 12:00:10 PM
It would help if you could measure the voltages on the collector and the emitter of the transistors.
This would give us a good impression if the circuit is working correctly.
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 13, 2015, 10:17:29 AM
I measured some stuff mentioned on the Bo Hansen page.
Quote
Connect the DI-box XLR connector to a mixer or preamp mic input with true 48 volt phantom powering.
If the LED is used and it light up, this is a first sign of health. (note: CHECK :D)

Use a digital voltmeter in dc mode and connect the negative test cord to the input jack ground and the positive test cord to the junction av the two 6,8k resistors, or the long leg of the LED if this is used, or the link if the LED not used, and here you should measure +24 volts, +/- 1 volt, if everything works ok.

The next measurment is to check symetrical clipping and headroom.
Move the positive test cord to the junction of 3,9k resistor, 10uF capacitor positive end and emitter on BC560 transistor, and here you should measure around +12 volts, +/- 0,5 volt.

I get different readings. What could be the problem? Will that explain the low output?
(http://i62.tinypic.com/21kmsfr.jpg)
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 14, 2015, 05:50:26 PM
Anyone? :)
Title: Re: Bo Hansen DI layout
Post by: audiophreak on February 14, 2015, 07:39:42 PM
   ... looks like  maybe only half phantom power getting to circuit  ??   check xlr connections / wiring ???
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 17, 2015, 07:28:42 AM

The voltage between XLR pin 1 to pin 2, and pin 1 to pin 3 should be around 36 volts, so this is quite ok.


I only got around 25 volts. Is that were my problem is?
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 18, 2015, 06:04:03 AM
Well, problem solved for anyone who might run into the same problem :)

I checked all the resistors and they seemed fine. So i swapped out a capacitor for a new one and now it all sounds wonderful.

Problem solved :)
A bit lucky, but hey.

Sounds really awesome with bass.
http://picosong.com/L7ec/

THANKS BO!!!!
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 19, 2015, 09:41:37 AM
:)
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 19, 2015, 09:43:58 AM
 8)
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 19, 2015, 09:44:26 AM
 ;D
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 19, 2015, 09:44:50 AM
 :P
Title: Re: Bo Hansen DI layout
Post by: RuudNL on February 19, 2015, 01:12:47 PM
Do you have a FPD file available for the front panel design? :P
Title: Re: Bo Hansen DI layout
Post by: philipNL on February 19, 2015, 01:30:28 PM
Hahaha :)
Title: Re: Bo Hansen DI layout
Post by: rockinrob86 on March 09, 2015, 05:44:36 PM
I am working on a veroboard version of this circuit (Thanks Bo!) and am running into a bit of an issue...

I managed to install the transistors backwards, but now I have the circuit squared away.

However, I am measuring 45 v at all of the above test points, including E on the BC560.  Does this sound like the transistors blew?  I have only ever worked on tube stuff and a few simple fuzz pedals, so I'm still learning all these transistor troubleshooting tips
Title: Re: Bo Hansen DI layout
Post by: G-Sun on March 11, 2015, 01:54:43 PM
Farnell gives me some 400 red leds.
What to shoot for?
round, 3mm, ??
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on March 11, 2015, 04:57:06 PM
the lower the current the better  :D
Title: Re: Bo Hansen DI layout
Post by: G-Sun on March 12, 2015, 04:24:59 AM
the lower the current the better  :D
Thanks!
20mcd? 120mcd? I have really no clue
(8.5mA    12V )
Title: Re: Bo Hansen DI layout
Post by: Humner on March 15, 2015, 11:50:02 PM
I know the feeling trying to find something so generic and simple like an LED from farnell and other parts suppliers.

Try this part number - HLMP4700  - I think that's as generic as you can get when it comes to a red LED.

I would even consider buying a multipack of generic LED's from a retail electronics store(one you can walk into). I did 12 years ago and I'm still going through them.
Title: Re: Bo Hansen DI layout
Post by: G-Sun on March 16, 2015, 03:55:38 AM
I know the feeling trying to find something so generic and simple like an LED from farnell and other parts suppliers.

Try this part number - HLMP4700  - I think that's as generic as you can get when it comes to a red LED.

I would even consider buying a multipack of generic LED's from a retail electronics store(one you can walk into). I did 12 years ago and I'm still going through them.
Thanks a lot!

I went with 2 leds,
- 3mm, round, 20, 12V, 8,5mA
- 3mm, round, 100mcd, 10,5mA, 14V
Hopefully one of those will be ok

DIY feels really like a nerd-hobby when looking up all those specs on data-sheets for small pennie-worth plastic objects :)
Title: Re: Bo Hansen DI layout
Post by: Harpo on March 16, 2015, 09:15:51 AM
I went with 2 leds,
You didn't.
You went with 2 LEDs with internally connected resistors instead.
You selected red LEDs for their lower breakthru voltage (about 1.8 - 2.0V) instead of green, yellow, amber, blue, white, whatnot, as already pointed out by Bo, but now chose a part for even worse 12V or 14V because of their internally connected current limiting series resistor (about (14V-1.8V)/0.0105A, giving 1160R). The needed current limiting resistor for the LED (if any) is already there (2 paralleled 6K81 on DI-pcb in series to 2 paralleled 6K81 inside the mixing desk/preamp).
Title: Re: Bo Hansen DI layout
Post by: G-Sun on March 16, 2015, 09:53:59 AM
You didn't.
You went with 2 LEDs with internally connected resistors instead.
You selected red LEDs for their lower breakthru voltage (about 1.8 - 2.0V) instead of green, yellow, amber, blue, white, whatnot, as already pointed out by Bo, but now chose a part for even worse 12V or 14V because of their internally connected current limiting series resistor (about (14V-1.8V)/0.0105A, giving 1160R). The needed current limiting resistor for the LED (if any) is already there (2 paralleled 6K81 on DI-pcb in series to 2 paralleled 6K81 inside the mixing desk/preamp).
Thanks for the reply, but I don't know if I understand :)
I plan to use one of the 2 leds above.
So, I need lower "Forward Voltage"?
Like LED, 3MM, RED, 100MCD, 643NM, 1.8V, 20mA part.nr: 2112100 ?
Title: Re: Bo Hansen DI layout
Post by: Zygimantas Laurutis on March 19, 2015, 04:08:25 AM
Hey,  please try mine. It's pretty squeezy :)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 25, 2015, 05:23:31 PM
Regarding the red LED, this should be an ordinary inexpensive LED of the simplest type of 3 to 5 mm, and nothing else.
 It shall not have any built-in resistor for current limiting, and it may also not be of the flashing type.

Note that the LEDs in this DI-box circuit is not connected in the same way as the LED is normally connected in other contexts, where it is usually connected in parallel with the voltage source and in series with a current limiting resistor.

In this DI-box circuit is the LED connected in series with the DI-box electronics supply voltage, and uses the 3.5 mA that the  DI-box electronics draws, in order to shine with a moderate brightness.

The LED should be connected with the long leg "anode" directed against the two 6.8 k resistors, with 100 uF electrolyte connected on the other side. (the short leg "cathode")
The connection can be seen on the schematic available on my webpage www.hansenaudio.se/techpage.htm

I have said it a hundred times, and will say it again.
 Use only red LED, do not use yellow, green, blue, white or any other color.
 The reason for this is that the red LED has a minimum voltage drop loss, and this results to the best headroom in DI-box.

--Bo
Title: Re: Bo Hansen DI layout
Post by: G-Sun on March 30, 2015, 04:46:39 AM
Thanks Bo!
And thanks for the project/design!

I'll get there with the led (order fro  China coming soon with low V red leds).

Seems like I'd done something wrong when trying the DI the other day (not working),
but I'll do the led and the missing ground to case, then I'll come back to it.

Happy Easter :)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 30, 2015, 10:22:21 AM
You should not keep you up at the LED, it's only a "phantom power on" indication. and is not important for the DI-box itself.

DI box works best without LED, ie that the two connection holes shall  be bridged with a wire instead.

Why order a special LED from China? As I said earlier, it is the simplest, most common, cheapest red LED that can be purchased at any hobby electronics stores around the world, no marvels at all.

If the DI-box is not working, always check two voltage checkpoints in the first place.
Over the 100 uF capacitor it should be 24 volts plus/minus some volts, and between ground and the emitter on the last BC560 transistor it should be 12 volts, plus/minus some volts.

Are these two voltages at these locations ok, the electronics should work right.
If there is sound out from the unbalanced tele-jack, and not from the balanced XLR, maybe the transformer is  wrong connected or defect.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 07, 2015, 11:11:25 AM
Bit of a newbie question...

I'm planning on building this DI box, But don't have any actual 5:1 transformers on hand.

I do however have a pair of Lundahl LL1521B's here, Which have a 1+1:2.28+2.28 turn ratio. Aside from that they are like the LL1540.

Will these be suitable if I wire the secondaries in series and use it backwards?
My maths makes that 4.56:1, Would that work ok?

Edit- I'm going to be doing this on perfboard so the number of pins on the LL1521B isn't an issue.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 07, 2015, 11:56:21 AM
Lee_M,

The LL1521B is a high impedance line- input transforme, so it will not match a microphone input impedance/load.

The best transformer types for my Di-box circuit is microphone input transformer with a ratio between 1:5 to 1:7 used backwards.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 07, 2015, 12:53:43 PM
Thanks Bo!

I've also got a Lundahl LL6804 (Same as LL7902 according to Lundahl, But with one less primary winding) that is currently doing nothing. They can be wired as 1:4 for microphone/line input, Would that be suitable for the DI?
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 15, 2015, 02:33:27 PM
I've just finished testing out my freshly wired DI and it is sounding sweet!  ;D

I've got it hooked up to a BBC LL/101SA at the moment, Using the centre tap on the primary for about 1:6 ratio and it's sounding very nice.
I also have a Lundahl LL4901 on the way so will test that out when it arrives.
The BBC xfmr is going to be tricky to electrically isolate from the chassis, Due to it's size, weight and mounting style...So the Lundahl may win out when I get to putting this in an enclosure.

I used tag board, The layout is far from perfect but I can draw it up and post here if anyone wants it.

A big thank you to Mr Hansen!
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 17, 2015, 11:37:25 AM
Ok, got it together now, Checking
Just noise from XLR.

Led is lighting up.

Over the 100 uF capacitor it should be 24 volts plus/minus some volts,
21,3V
Quote
and between ground and the emitter on the last BC560 transistor it should be 12 volts, plus/minus some volts.
10,2V
Quote
Are these two voltages at these locations ok, the electronics should work right.
If there is sound out from the unbalanced tele-jack, and not from the balanced XLR, maybe the transformer is  wrong connected or defect.
So, seems like voltages are ok?

Then transformer, Haufe ST8456:
I've mounted it with text facing edge, facing away from the transistors. Can anyone confirm direction?

Edit: Seems like the transformer is fool-proof for direction. 3+4 legs.

So, Bo, your guess is bad transformer then?
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 17, 2015, 12:19:10 PM
your guess is bad transformer then?

I'm not Bo, But you should check the DCR on each of the windings using a multimeter. If any of them are reading "open circuit" then you likely have a damaged winding...Which would suck, But it does [very rarely] happen.
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 17, 2015, 03:37:25 PM

I'm not Bo, But you should check the DCR on each of the windings using a multimeter. If any of them are reading "open circuit" then you likely have a damaged winding...Which would suck, But it does [very rarely] happen.
Thanks! I'll do that.
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 20, 2015, 03:47:22 AM
Then transformer, Haufe ST8456
Man, that's a hard thing to desolder..  :o
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 20, 2015, 04:13:26 AM
Haufe ST8456 (http://api.viglink.com/api/click?format=go&jsonp=vglnk_14295175371288&key=27f13a138b9c18bbb26d1b79059da4a7&libId=i8plu0w101000n0n000DAjhvsxsc6&loc=http%3A%2F%2Fgroupdiy.com%2Findex.php%3Ftopic%3D39570.0&v=1&out=http%3A%2F%2Fwww.silentarts.de%2FDIY%2Fsales%2FST8456_Data.pdf&ref=http%3A%2F%2Fwww.google.no%2Furl%3Fsa%3Dt%26rct%3Dj%26q%3D%26esrc%3Ds%26source%3Dweb%26cd%3D1%26ved%3D0CB4QFjAA%26url%3Dhttp%253A%252F%252Fgroupdiy.com%252Findex.php%253Ftopic%253D39570.0%26ei%3D3LQ0Va-sG4KtsgH68YG4Bg%26usg%3DAFQjCNG8QHjIVdob-_tfKnqlBohIsITjvg%26sig2%3DO7aHcXapfrGNcpmszC5cyA%26bvm%3Dbv.91071109%2Cd.bGg&title=%5Bsilent%3Aarts%5D%20MIG%2051X%20%26%20VPR%20Racks%2C%20Modules%2C%20D-LA2A%20and%20more&txt=Haufe%20ST8456)

Reading
Pin 3-4: 55,2ohm
Pin 1-2: 54,2ohm
Pin 5-6: 65,7ohm

Seems ok, doesn't it?
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 20, 2015, 08:01:45 AM
I'm not familiar with the specs for the transformer, But if you'd broken a winding you wouldn't get anything on your meter from that pair of pins.
However, I'd expect the higher ratio side of the transformer to have a significantly higher DCR than the other winding...But I'm far from an expert.

I'm not sure what to suggest next (I'm only a rookie, after all!) so hopefully someone more experienced will step in.
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 20, 2015, 12:07:56 PM
However, I'd expect the higher ratio side of the transformer to have a significantly higher DCR than the other winding...
Thanks! Yes, pin 1-3 is spec. ca. 120ohm, so 55+54ohm = 109ohm should be fine.
But, 5-6 has spec. ca. 600ohm (and I read 65,7). So, could indicate an error I guess. Have to double-check.
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 20, 2015, 01:18:02 PM
But, 5-6 has spec. ca. 600ohm (and I read 65,7). So, could indicate an error I guess.

That sounds like it could be your problem, It's definitely worth checking.
Maybe you got one with a manufacturing defect or possibly you received another model of transformer that was wrongly labelled?

By the way, Where can I find the specs for the Haufe?
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 20, 2015, 01:23:29 PM
By the way, Where can I find the specs for the Haufe?
Here: http://api.viglink.com/api/click?format=go&jsonp=vglnk_14295175371288&key=27f13a138b9c18bbb26d1b79059da4a7&libId=i8plu0w101000n0n000DAjhvsxsc6&loc=http%3A%2F%2Fgroupdiy.com%2Findex.php%3Ftopic%3D39570.0&v=1&ref=http%3A%2F%2Fgroupdiy.com%2Findex.php%3Ftopic%3D36569.new&title=Bo%20Hansen%20DI%20layout&txt=Haufe%20ST8456&out=http%3A%2F%2Fwww.silentarts.de%2FDIY%2Fsales%2FST8456_Data.pdf
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 20, 2015, 01:30:21 PM
But, 5-6 has spec. ca. 600ohm (and I read 65,7). So, could indicate an error I guess.

That sounds like it could be your problem, It's definitely worth checking.
Maybe you got one with a manufacturing defect or possibly you received another model of transformer that was wrongly labelled?
Double-checked. My fault.
New reading 641ohm.
Was too quick with my new DMM.

So, transformer seems fine.
I'll solder it back on.
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 20, 2015, 01:40:17 PM
So, transformer seems fine.

That's good news!  :)

As far as troubleshooting your DI, I'm not sure what to suggest...Are you getting any signal from the 1/4" monitor amp output?

It could be worth posting some pics of your board, I'm not familiar with the PCB layout but someone else may be able to visually ID your problem.
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 20, 2015, 02:03:25 PM
Thanks!
Yes, here are some photos:
https://drive.google.com/folderview?id=0B2EgFUTJT9ZtfmlaYWM2X3BTSVc2T2NzeFVOR0pIZnZZOEgxYmFmcXJPeU9rX29OU29jVG8&usp=sharing
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 20, 2015, 02:25:24 PM
The soldering, component placement and wiring looks good to me, but I did mine on tag board rather than PCB so my layout is quite different and hard to compare.

I would get a magnifying glass and multimeter and check for tiny solder bridges between any closely positioned pads on the PCB.
Your soldering is very tidy, But it's possible there could be a thin sliver of solder hiding somewhere it shouldn't be.

Good luck!
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 20, 2015, 02:49:37 PM
Thanks!
I'll check your suggestions.
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 21, 2015, 03:14:33 AM
Are you getting any signal from the 1/4" monitor amp output?
No, nothing.
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 21, 2015, 03:47:42 AM
I would get a magnifying glass and multimeter and check for tiny solder bridges between any closely positioned pads on the PCB.
Your soldering is very tidy, But it's possible there could be a thin sliver of solder hiding somewhere it shouldn't be.
Checking with mag.glass. Can't see anything.

So, it's down to a faulty component then I guess.
What's most likely?
A bad capacitor couldn't explain this, could it?
So, a transistor is most likely? Or does my voltage-reading above indicate that they are working correct?
(btw: I just assumed E was for emitter, checking. seems right)
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 21, 2015, 04:03:03 AM

If the DI-box is not working, always check two voltage checkpoints in the first place.
Over the 100 uF capacitor it should be 24 volts plus/minus some volts, and between ground and the emitter on the last BC560 transistor it should be 12 volts, plus/minus some volts.

Are these two voltages at these locations ok, the electronics should work right.
If there is sound out from the unbalanced tele-jack, and not from the balanced XLR, maybe the transformer is  wrong connected or defect.
Double-checking here, and getting other results..

Over the 100 uF capacitor: 0 ohm
 between ground and the emitter on the last BC560: 0ohm
(there's only one 560, isn't it? and mine is a 557C)

Edit: Man, what a foghead, voltages, not ohm..
New check..
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 21, 2015, 06:19:12 AM
In an earlier post you gave your voltage measurements, They were close enough to the specified voltages that I wouldn't suspect a transistor.

As your voltages test ok and the transformer seems fine, My next port of call would be to check the 10uf cap between your BC557C and the 10k output resistor/transformer.
Maybe test to see if there is any DC on the negative side of the cap while the unit is running?

What kind of noise do you get on the output?

Are the caps all correctly oriented, with regards to polarity?
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 21, 2015, 02:26:59 PM
I just finished getting mine into the enclosure, Had a couple of slight bumps with metalwork but I'm really happy with how it turned out.

I had to give up on the BBC LL101SA that I was originally using, It just about fit into the enclosure but would have left literally no margin for error when it came to making mounting holes.
Instead I used a Lundahl LL4901, It was designed for PCB mounting so I had to get creative for using it with tag board...Made a "sandwich" out of 3mm bakelite squares, Drilled a hole in each corner of the two pieces of bakelite, Then drilled 8 small holes in one bakelite piece for the transformer pins to poke through....Probably should have used thinner bakelite as it didn't leave much of the tx pins accessible, but it worked out ok.
Then added some 20mm nylon spacers for the corner screws (between the two pieces of bakelite) and all was well- Full isolation from the chassis, Yet still chassis mounted.

I just gave it a brief test and it sounds equally great on guitar, bass and rhodes...so I guess I should build one DI box for each instrument?  ;D

Thanks again to Mr Bo Hansen for a great project!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 28, 2015, 04:01:33 AM
G-Sun,

You have connect the tele-jacks on wrong pin side.

Go to www.hansenaudio.se/techpage.htm
look on the pictures, and compare, you will see the fault.

--Bo
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 28, 2015, 05:24:51 AM
G-Sun,

You have connect the tele-jacks on wrong pin side.

Go to www.hansenaudio.se/techpage.htm
look on the pictures, and compare, you will see the fault.

--Bo
Wow, thanks!
I didn't know there was any differences for side of the jack.
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 28, 2015, 09:13:33 AM
G-Sun,

You have connect the tele-jacks on wrong pin side.

Go to www.hansenaudio.se/techpage.htm
look on the pictures, and compare, you will see the fault.

--Bo
Looking at the datasheet for the jack socket
http://no.farnell.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=15001&langId=47&urlRequestType=Base&partNumber=148267&storeId=10169
I don't understand
http://www.farnell.com/datasheets/511561.pdf
As far as I can understand it's no difference between the sides.
??
Title: Re: Bo Hansen DI layout
Post by: Lee_M on April 28, 2015, 09:21:50 AM
The terminals on one side of the jack switch "out" when a jack is plugged in, Breaking the connection. Check with a multimeter between the terminals on each side of the jack to see for yourself.
If you have soldered your board to the switched terminals then your signal to the socket will be cut whenever you plug a jack into it.

I actually did the same thing wrong with a fuzz pedal I built using switched jacks, Didn't realise the fault and spent literally days replacing components and debugging before a mate saw some of those jack sockets laying around in my house and commented how cool the switching mechanism is... :-[
Title: Re: Bo Hansen DI layout
Post by: G-Sun on April 28, 2015, 01:24:41 PM
You have connect the tele-jacks on wrong pin side.
The terminals on one side of the jack switch "out" when a jack is plugged in, Breaking the connection. Check with a multimeter between the terminals on each side of the jack to see for yourself.
If you have soldered your board to the switched terminals then your signal to the socket will be cut whenever you plug a jack into it.

I actually did the same thing wrong with a fuzz pedal I built using switched jacks, Didn't realise the fault and spent literally days replacing components and debugging before a mate saw some of those jack sockets laying around in my house and commented how cool the switching mechanism is... :-[
Working :)

You were of course right. Thank you very much!
(I just assumed those pins were continues, but checking, yes, they're switching of when jack is inserted)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on May 24, 2015, 05:55:40 PM
Hi guys,

Just want to tell  that the new PC-cards for my DI-box is ready and will soon be sold through Silent Arts in Germany.

You can place your order at The White Market here on the forum, and Silent Arts will soon announce it there.

The new pcb version is the same as the previous, but has received some small improvements in the text and some other things.

Best from
Bo
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on May 25, 2015, 06:42:50 AM
Thanks Bo. PCBs should arrive tomorrow.

(http://www.silentarts.de/DIY/BoDI/BoDI-rev2PCB-01.gif)(http://www.silentarts.de/DIY/BoDI/BoDI-rev2PCB-03.gif)
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on May 26, 2015, 04:26:15 AM
PCBs are now available (http://groupdiy.com/index.php?topic=39570.msg488632#msg488632)
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on May 29, 2015, 03:58:26 AM
Lately I've been making several of these and testing different transformers.  I'm planning on replacing all my Radial Pro DI with these and some point to point hardwired passive guys. I thought I would share my Mouser cart with those who plan on buying these PCBs and building them in the States:

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=12eddc2712

This is based on the new schematic on Bo Hansen's website and I use it in all my builds.

I'm using audio grade electrolytics and WIMA film caps. Most of the resistors are Vishay and connectors are Neutrik. Total price is under $11. The stock will change from time to time so make sure and scroll down and see if anything is listed as back ordered. I didn't include any headers as what's pictured in the new rendering as I just wire connectors directly to the board. Also, does not include an enclosure.

Hopefully this will be useful to the peoples. I'd check from time to time to see if availability for any of the items has changed.

Paul
Title: Re: Bo Hansen DI layout
Post by: mschuerm on May 30, 2015, 09:17:45 PM
Just wanting to join in on the chorus of praise for this DI box. I had been using either no DI or a horrible Rolls Matchbox before I built this Wednesday night. Used the OEP and all suggested components and mounted in 1590TBK.  Tested Friday with a PRS with Dragon II passive humbuckers into a Classic API VP26 with the gar2520 opamp---never heard a DI guitar sound so clear! And the output of this DI! I had to attenuate the VP26 even with its gain all the way down to keep my digital level around -18 (I guess this is normal?). Tonight I plugged a freshly setup Fender Jazz Bass with passives into the same signal chain. Again, cannot believe the clarity and full-range sound! Cranked the gain on the VP26 and attenuated back down to digital-safe levels, and was blown away by the grit/balls of the tone. Thanks Bo and everyone involved in this project---don't think I'll ever need another DI---except maybe another Bo for a stereo pair!
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on May 31, 2015, 01:42:29 AM
Wanted to share some photos of the latest one that I built. This is the second I put together with a Sowter 9045. These things are huge! I had no idea as I couldn't find dimensions on their website. This configuration was chosen with bass in mind, as according to the 9045 specs it goes all the way down and all the way up. The first one made like this is currently being used by the bass player for the tour I am currently on. He had been using a Neve clone of some sort. He also took this for a session he did recently and received many compliments from the engineer. The transformer was wrapped in electrical tape to prevent the case from touching the enclosure and was zip tied to some small L brackets that I made. The LED I used was a standard clear red one that requires slightly less current and voltage that what is currently on the BOM posted previously. I drilled a small hole then used a counter sunk bit from the inside and removed just enough material so the dome barely stuck out past the enclosure then hot glued it in place. The LED in this build is no longer being made, so I listed the panel mount in the BOM for ease availability and to look more professional for those of you who know how to do the fancy metal work. If there is better suited LED for this design please let me know and I'll gladly change the Mouser cart.

I later went back and hot glued everything that I thought could come loose as I'm building them with touring in mind. I can't have them failing and then be showered with scorn from my compatriots.

I still have an OEP, Carnhill, Haufe, and a Cinemag to build to test on various instruments, primarily acoustic guitar. I'll report back when I get to finishing them up.

Paul
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on May 31, 2015, 01:44:11 AM
And here's the outside.
Title: Re: Bo Hansen DI layout
Post by: DerEber on June 05, 2015, 05:45:47 AM
Did a quick build with things I had laying around.

(http://twin-x.com/groupdiy/albums/userpics/10004/000026-Bo-kleiner.jpg)

Thats how I work sometimes :)
Title: Re: Bo Hansen DI layout
Post by: DerEber on June 05, 2015, 05:47:48 AM
stuffed pcb:

(http://twin-x.com/groupdiy/albums/userpics/10004/000027-Bokleiner.jpg)


and back:

(http://twin-x.com/groupdiy/albums/userpics/10004/000028-Bo-kleiner.jpg)


Title: Re: Bo Hansen DI layout
Post by: DerEber on June 05, 2015, 05:50:13 AM
Fits in perfectly:

(http://twin-x.com/groupdiy/albums/userpics/10004/000029-Bo-kleiner.jpg)

Outsideview:

(http://twin-x.com/groupdiy/albums/userpics/10004/000030-Bo-kleiner.jpg)

Now I am on the way of building a Stereo one with PCBs a friend from the German forum did.

best Greetings,
Stephan

Title: Re: Bo Hansen DI layout
Post by: Woot on June 14, 2015, 09:52:23 AM
Hey Bo et al....

I am looking forward to receiving my boards from Volker soon.

I'm going to do a rack of them and am considering putting a 3PDT switch on the front to toggle between rear and front xlr's....

Still deciding whether this is a bit OTT with extra cost of xlr's etc but it could be handy..

Would this mess with the grounding scheme/ground loop suppressor at all?

Cheers,

matt
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on June 14, 2015, 10:02:20 AM
Connect pin1 on the XLRs together and only switch pin2 & 3 - this is how I would do it.
Title: Re: Bo Hansen DI layout
Post by: Woot on June 14, 2015, 10:56:54 PM
^ Will do, thanks!
Title: Re: Bo Hansen DI layout
Post by: Woot on June 19, 2015, 09:42:17 PM
Hi Guys,

Could someone please confirm that either of these pair would work well?

Cheers,

Matt

http://ampslab.com/trans_2sa965.htm
http://ampslab.com/trans_2sc2705.htm
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 21, 2015, 03:50:48 AM
Matt,

These two transistor types are driver transistors for power amps, and is unnecessarily powerful for use in this DI box.

Instead, choose some of the types that I have recommended to my help page www.hansenaudio.se/techpage.htm

--Bo
Title: Re: Bo Hansen DI layout
Post by: Woot on June 21, 2015, 10:30:15 AM
Hi Bo,

Thanks for the info.

I was trying to find transistors that matched your suggestions earlier in this thread: "Vceo 30 volt as minimum, hFE from 200 and up, and fT from 100 mHz and up.", but was struggling to match any available ones up with these specs ... the Toshiba 2SC2240 match this but are not available reliably that I can find.

I am 100% sure I am making this more complicated than it needs to be...  :o

I'll  use some of the ones on your list.

Matt
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 21, 2015, 11:13:04 AM
Matt,

You can use almost any general purpose NPN / PNP "amplifier" small signal transistors on the market, it is not necessary to use extremely fine transistoret as 2SC2240 / 2SA970. You can certainly find some of the BC or 2N types at your local electronics store, I recommend on my help page.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Woot on June 21, 2015, 07:10:18 PM
Thanks Bo!
Title: Re: Bo Hansen DI layout
Post by: kosi on June 28, 2015, 06:24:21 PM
Could someone verify, that this is the correct pinout for a Sowter 9045  ?
I gif is original from Sowter, I added the numbers.
I don't know, what to do with the white lead ?

thanks,
Andreas
Title: Re: Bo Hansen DI layout
Post by: monkeyxx on June 28, 2015, 06:43:16 PM
Could someone verify, that this is the correct pinout for a Sowter 9045  ?
I gif is original from Sowter, I added the numbers.
I don't know, what to do with the white lead ?

thanks,
Andreas

Looks like  a center tap.  I think the best idea is to not use it at all, just get it out of the way and ignore it.

Center tap wiring is beyond my comprehension, someone with more knowledge would have to tell me why you would ever want to use one.  Most transformers don't have them.
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on June 29, 2015, 02:40:13 AM
You can ignore the white lead with the 9045 in the Bo Hansen circuit. Also, if you don't already have one, you should know that these transformers are very big and will need a decently size enclosure to fit everything in there. (See my earlier post with a pic to get an idea of it's dimensions).

I've built two DIs with the 9045's and use them exclusively on bass. They sound exceptional with in ear monitors and in a PA. Very big, very clear, even with the low notes. It seems to perform as the spec sheet states with minimal loss even down to 10 Hz.

Thanks!

Paul
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on June 29, 2015, 02:48:31 AM
Could someone verify, that this is the correct pinout for a Sowter 9045  ?
I gif is original from Sowter, I added the numbers.
I don't know, what to do with the white lead ?

thanks,
Andreas

Looks like  a center tap.  I think the best idea is to not use it at all, just get it out of the way and ignore it.

Center tap wiring is beyond my comprehension, someone with more knowledge would have to tell me why you would ever want to use one.  Most transformers don't have them.

For this particular transformer, the center tap is to allow phantom power to pass through when used in a microphone design. It's in the spec sheet on Sowter's website.


Paul
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 29, 2015, 04:26:45 AM
Sowter 9045, connected in 5:1 configuration.

Red to amp output/10 uF cspasitor.
Blue to ground
White cable not used (isolated)

Orange to XLR pin 2
Green to XLR PIN 3
Yellow and Grey soldered together and isolated.

Black cable  to the DI-box metal case, if the transformer can are bolted in the metal case.
But if the transformer can is grounded in the pc-board electronic ground, (isolated from the metal case) the black cable shall also be connected to the PC-card electronic ground..

--Bo
Title: Re: Bo Hansen DI layout
Post by: kosi on June 29, 2015, 04:32:29 AM
thanks everybody  ;D
Title: Re: Bo Hansen DI layout
Post by: kosi on July 13, 2015, 06:22:54 AM
Hi everybody,
I have completed my second DI Box with the Sowter and today, I made a very quick comparison between the first one  (Haufe) and the Sowter into an Awtac Channel Amp . Third contender is the DI of the Awtac. I played a Höfner Clubbass with flat wounds .

The difference between Sowter and Haufe is mini, I couldn't tell the difference, after many switchovers from one file to the other I had the feeling, that there's a tiny bit more bass in the Sowter, which could also be the nature of the other take.
The most Bass has the Awtac, but both DI boxes have more grid, more definition, which I really like.

I made some screen shorts with DMG audio Dualism, if anybody wants, I can send the audio files

thanks again for all the participant parties !!!
Title: Re: Bo Hansen DI layout
Post by: kosi on July 13, 2015, 06:23:22 AM
Haufe
Title: Re: Bo Hansen DI layout
Post by: kosi on July 13, 2015, 06:23:50 AM
Awtac
Title: Re: Bo Hansen DI layout
Post by: Humner on August 03, 2015, 03:27:04 AM
I finished a 2 channel version of Bo's DI.

My first test was fender strat through this DI and then through my racked PM1000 channels. Really happy with how this sounds - very impressive.

(http://www.thraxeh.com/Pics/bodi/bodi1.jpg)
Title: Re: Bo Hansen DI layout
Post by: Cade Allen on August 29, 2015, 06:32:09 PM
Can somebody post the link to buy the PCB?! I only saw it on PCBgrinder, but that was for an updated version called the "DI28".
Thanks!  8)
Title: Re: Bo Hansen DI layout
Post by: Humner on August 30, 2015, 01:56:59 AM
Can somebody post the link to buy the PCB?! I only saw it on PCBgrinder, but that was for an updated version called the "DI28".
Thanks!  8)

[silent:arts] - http://groupdiy.com/index.php?topic=39570.msg488632#msg488632

I have a question - I want to power one of these from a 15V DC supply. Do I need to may any changes to the circuit?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 30, 2015, 07:40:19 AM
Humner,

Do you mean 15 volts phantom from a mic input, or feed the DI-box from a external 15 volts power supply ?

--Bo
Title: Re: Bo Hansen DI layout
Post by: Humner on August 30, 2015, 08:31:35 AM
external regulated 15v supply.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 30, 2015, 10:11:13 AM
Humner,

Ok, remove the two 6.8 k resistors and connect a pure stabilized +15 volt directly to the point that the two 6.8 k resistors were connected together.

And of course the 15 volts -/ground to the circuit board ground rail, for example, minus on the 100 uF capacitor.

This is all you need to do, but the downside is less headroom because the electronics get 10 volts less voltage feed and and also slightly worse driving of the transformer, because less current in the output transistor.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Humner on August 31, 2015, 04:02:18 AM
How about a bipolar supply? 15 +/-  and then use a 1.8k resistor to bring down to 24v

Will this work OK?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 31, 2015, 07:15:13 AM
Humner,

Do you mean to drive the DI-box electronics with 15 volt symetrical/bipolar plus and minus with mid ground ?

Sure, it can be done, but too much changes on the PCB as the earth system must be changed completely.

I recommend that you use 15 volt that we talked about earlier, or use 24-volt power supply.

Can you explain for me why you should use DI-box without 48-volt phantom power, and how you intend to use it.
Perhaps there is a better solution for you ?

--Bo
Title: Re: Bo Hansen DI layout
Post by: Humner on August 31, 2015, 08:00:12 AM
hi Bo,

Thats right, I have an existing microphone preamp circuit I built using a 15v +/- supply. I never built in phantom power as its used primarily for dynamic microphones. I wanted to retro fit one of your DI boards inside the enclosure to include a switchable DI option.

I think I was just worrying that I might not get the full potential out of your DI.

My PSU starts with a 15v AC transformer, so maybe I build a separate supply with a voltage multiplier circuit to generate 24volts. Your DI only draws a small current so it shouldn't strain the transformer.

but really, I am probably just over thinking and I should just use the 15v supply I have and keep it simple.

Thanks for your help.
Title: Re: Bo Hansen DI layout
Post by: Treb on October 02, 2015, 11:27:56 AM
Hi all!

Thinking of building one too. Question about those caps in the signal path, is there any benefit from spending a bit more money and use quality caps here instead of whatever there's in my parts bin? The 10 MFD electrolytic between Q2 and the transformer in particular, would the sound quality benefit from using a foil capacitor (like the ones found in loudspeaker crossover filters) in this location? I know these can be pretty big...
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on October 03, 2015, 07:13:02 AM
Treb,

In this design it is not necessary to use better than standard components as Jamicon 85 degree electrolytes or the like, and the standard carbon film resistor as Firstron or similar brands.

But if you want to increase the component quality, use 105 degree Panasonic FC or Elna RJH electrolytics , Wima film capasitors, Vishay metal film resistors or similar good brands.

Never use the Hi-Fi world imaginative components such as "super or wonder" caps and the like, we are in the real world.

The most important thing is to use good transistors not substitute fake types from China, use brands like Philips, SGS/Ates, Motorola, National, Fairshild.
And of course, that you use one of the three transformers I have recommended.

Carefully follow all the advice on assembling, connector types, grounding, and much else, then you will get a good quality and results when you're done with your DI-box DIY.

You'll find all the advice on my website www.hansenaudio.se/techpage.htm

--Bo
Title: Re: Bo Hansen DI layout
Post by: G-Sun on November 06, 2015, 08:40:09 AM
I'd just like to report back:
I've struggled with my bassguitar-sound before.
Now, using The Bo Hansen DI, it sound much better  ;D
Thanks a lot!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on November 06, 2015, 10:53:41 AM
G-Sun,

Thanks, Tack, for your raport,
verry glad ti hear that.

Best from
--Bo
Title: Re: Bo Hansen DI layout
Post by: Treb on January 08, 2016, 10:53:27 AM
Another DI sees the light of day! Worked right away, the red led is working but is rather dim. Is that correct? For the nerds, Lundahl 1538, Vishay-Dale resistors, Wima, Panasonic and Vishay-Roederstein caps. Hammond  1455N1201 case, Neutrik connectors, 2mm frontpanel from Schaeffer AG.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 08, 2016, 11:29:31 AM
Treb,

If it is a normal 4 mm red LED, it shall shine quite bright, if every thing else is ok.

But if you have chosen a special LEDs with integrated series resistor, then it will light dimly, and the DI-box electronics will get too little voltage feed.

--Bo--
Title: Re: Bo Hansen DI layout
Post by: Treb on January 08, 2016, 12:08:28 PM
Thanks Bo,

I did some probing:

input ground -> LED :  25.1 volts (+24 volts, +/- 1 volt)
input ground -> junction of 3,9k resistor etc. : 11.56 volts (+12 volts, +/- 0,5 volt)

Everything within spec I guess,  must be the LED. As fas as I know it's a bog standard LED. Perhaps it's because I'm so used to those super bright blue LEDs...  :-\

Attached is the Front Panel Designer file for those wanting to use it for their own purposes, just rename the extension to FPD.
Title: Re: Bo Hansen DI layout
Post by: Treb on January 08, 2016, 12:40:42 PM
Gut shot before I close it again.

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 08, 2016, 01:08:36 PM
Treb,

Very nice job.

--Bo--
Title: Re: Bo Hansen DI layout
Post by: Treb on January 08, 2016, 01:12:34 PM
Thanks Bo! I wanted to have the front panel lettering filled in with yellow paint. Blue and yellow to pay tribute to its Swedish origin. Too bad Schaeffer couldn't do it. I did it myself with a LacquerStik. The Swedish design, the DIY aspect and the blue/yellow colour combination brings about a kinda IKEA-vibe. ;-)

I haven't heard it yet as I'm missing some plugs and  cables to hook it up... Will report back.
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on January 14, 2016, 03:35:44 AM
A couple of quick notes for the peoples looking to build these sweet little DIs:

The Sowter 9045's sound phenomenal on bass. The data sheet they published on their site shows it nearly flat all the way down and pretty much all the way up. At least in the live environment you can instantly hear the not only all the low notes but significant clarity of the notes over standard fare DI's. I've lent one to a friend for a session he was playing bass on and he told me he got many compliments from the engineers for the sound they were getting with this DI paired with the Sowter. However, one must be aware that it is a very large transformer, and it will work if you are planning to make compact versions of this DI.

The CMO-5/200CT that is listed on Bo Hansen's site has been replaced by the CM-9711. I used this one for a pair and lent it to an engineer and he randomly used it to record keyboards and he was very happy with the results. The idea was to get it to get instruments to cut a little more in a mix as Cinemags in the passive DI's have worked well for this on acoustics in a live setting.

I still haven't tested the ones I built with Carnhill transformers. Hopefully soon.

Thanks,

Paul
Title: Re: Bo Hansen DI layout
Post by: Erazorblade on January 16, 2016, 05:05:12 AM
Hi guys,

excuse me for the maybe inappropriate question, but where can I order the pcb's since the link in the 1st post seems to be broken?

Thank you very much.
Title: Re: Bo Hansen DI layout
Post by: Treb on January 16, 2016, 07:26:08 AM
Volker sells them. He's known as [silent:arts] on the forum. Try reaching him by PM.
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on January 18, 2016, 09:36:05 AM
White marked link (http://groupdiy.com/index.php?topic=39570.msg488632#msg488632) is working again  8)
Title: Re: Bo Hansen DI layout
Post by: Matt55 on January 25, 2016, 09:12:13 AM
Hello Bo,

I am looking to build 2 of these for an acoustic guitar, 1 to use, 1 as spare (also I will have a stereo pair at that point). I have a couple of questions that would be good if you could answer :)

1) Is the Lundahl LL1538 worth the extra money over the Haufe ST8456 and what are the sound/sonic differences between the two models?

2) What is the hole size and spacing between the holes on the pcb for the xlr, input and output. I was thinking about using terminal blocks or connectors but to order I need to know the above measurements.

I was going to use the mouser bom which seems to contain most other things needed for the build.

Thanks for your time and effort on this project much appreciated :)

Regards,

   Matt
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on January 25, 2016, 11:58:50 AM
2) What is the hole size and spacing between the holes on the pcb for the xlr, input and output. I was thinking about using terminal blocks or connectors but to order I need to know the above measurements.
2,54mm
Title: Re: Bo Hansen DI layout
Post by: Matt55 on January 25, 2016, 02:13:45 PM
Much appreciated, Thank you Volker :)
Title: Re: Bo Hansen DI layout
Post by: Treb on January 25, 2016, 06:08:20 PM


1) Is the Lundahl LL1538 worth the extra money over the Haufe ST8456 and what are the sound/sonic differences between the two models?

Worth the money is something only your ears can tell. As always the law of diminishing returns applies here too.

Regarding the Lundahl:

Quote
Lundahl's transformers are extremely neutral and clean, with no ringing or overshoot. (may sometimes be too good to be a transformer)

Haufe ST-8456 is a very nice transformer, but Lundahl LL-1538 is a bit better, and LL-1538XL (extra lardge) have a bit more headroom in the low end.


I have done some tests and compare Lundahl LL1538, Haufe ST8456 and Walters OEP A262A3E, in my DI-box circuit.

Lundahl and Haufe have near same behavior from 100 Hz and up, but Haufe are a bit better in low end small signal distortion, and Lundahl have lower distortion in low end near saturation point.

Both have a very good square wave response, and have 14 dB loss with 1 kohm total load.

OEP have approx. 10 times higher distortion from 100 Hz and down, and have also higher distortion in the high end, but have ok square wave response, slightly rounded, with out ringing or overshoot.
Because the 6,45:1 ratio, it have 16 dB loss.

All three sounds nice in my DI-box, but Lundahl LL1538 are still the best with a steady and clean low bottom and a fast and clear high end.

--Bo

It's all in this thread. Do read it all, lots of good info! Good luck.
Title: Re: Bo Hansen DI layout
Post by: Matt55 on January 26, 2016, 09:50:36 AM
Wow thanks Treb!!!

I think I am going to go with the Lundahl. I actually did use the search function at the top of the page but I didnt see that post...

Maybe that info should be added into the page 1 post so that others can read (I know we should read all 38 pages but...) Its valuable info that can be used when making the transformer decision!

Thanks, Matt
Title: Re: Bo Hansen DI layout
Post by: Treb on January 26, 2016, 05:33:18 PM
Bo's comments about the transformers isn't from a single post. It's what I cobbled together from's three (four perhaps) of Bo's posts. I did a search for Bo's posts...  :)

All 38 pages? That's nothing! If you ever want to make something like a Millett Starving Student (468 pages), a Pass B1 preamp (405 pages) or a Pass F5 power amp (1503 pages, gulp!) you're in for a treat!  ;D
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on January 26, 2016, 10:14:53 PM
Treb and Matt55,

Thank's for you reminding me,
I will add the info on my DIY page as soon as possible.

Please read my DIY instructions on www.hansenaudio.se/techpage.htm where you will find the most important about component selection, construction proposals and test instructions.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Matt55 on February 02, 2016, 07:04:34 PM
So, I got all the parts together today and finished a stereo pair. Both worked beautifully at first switch on!

Built with the standard BOM, Lundahl LL-1538 , red LED and the Hammond 1590-TBK, with all inputs and outputs mounted on one side (its tight which is why I guess not many people chose this route but possible) because it suits the way I set the stage.

So I tested both by just listening to them over my pa in my front room while my brother played away on his Yamaha CPX900. Both sound beautiful and add a musicality not found when the guitar is plugged directly into the mixer via 1/4 unbalanced jack. The high end is smoother out but more present with that classic transformer sound, and the bass is rounder/fuller. Definitely very pleased and cant wait to use them at the next gig. Very pleased :)

Thanks to Bo, for the great design and clear instructions and thanks to Volker for providing and supplying the PCBS!

Thanks,

  Matt



Title: Re: Bo Hansen DI layout
Post by: Treb on February 03, 2016, 02:18:59 PM
So, I got all the parts together today and finished a stereo pair.

You know the drill, pics or it didn't happen...  ;)
Title: Re: Bo Hansen DI layout
Post by: btwester on February 04, 2016, 07:05:51 AM
Hi everybody, my first post in here!

I've built a couple of these things before, one with the 1538 and one with the OPA and can hear the possibilities for different applications. 
Due to some earthing issue (my guitar strings touched a metallic lampshade) one of these fried, or the pcb-traces fried pretty much, the trafo reads good. Just glad it protected my computer and mixer, so now I'm building a couple more.

While I can build these upon instruction, my understanding of any circuit topologies is pretty rudimentary. I've heard these things about getting more mojo with choosing certain components for different applications, like using carbon-resistors in some tube guitar amps circuitry or to get a more hifi-sound using polypropylene caps instead of polyester.

So here lies my question for this particular application, Mr. Hansén recommends to use either polyester or polypropylene caps for this on his tech-page.  Everybody seem to choose the polypropylene ones but would choosing for example a Nichicon XY-type or even  Mustard-cap, both which they recommend for "vintage"-style circuits have any impact on the sound, and I know were talking about some very miniscule nuances or responses here? I am  guitarist and don't really look for Hifi, but charming distortion and saturation :-)

Thanks

-btwester

 
Title: Re: Bo Hansen DI layout
Post by: Treb on February 05, 2016, 07:45:42 AM
I have a suggestion for a PCB revision, should it ever happen. Why not add test points to the PCB?  This way it's easy to perform the two tests described on Bo's techpage. With plated through holes on the PCB the tests could be performed both sides of the PCB.
Or why not add a possibility to hook up 48 volts externally from a suitable PSU? This way you could use the DI to plug into a non-phantom powered balanced input.  Just a thought...
Title: Re: Bo Hansen DI layout
Post by: Matt55 on February 09, 2016, 10:58:00 AM
Ok so as you asked nicely Treb.

Here are my builds.  They are not the neatest things I've ever built but they dont really need to be! They work beautifully and thats all that matters.

Thanks,

 Matt

Title: Re: Bo Hansen DI layout
Post by: Treb on February 10, 2016, 01:08:55 PM
Nice clean builds Matt! BTW, why did you choose those beefy resistors?
Title: Re: Bo Hansen DI layout
Post by: Matt55 on February 10, 2016, 02:19:25 PM
Nope and I wasn't expecting them but thats what comes with the standard Mouser BOM from the first page of the thread...

I noticed you used some upgraded parts in yours but I'd already ordered the BOM and thought that the transformer would make the most difference anyway so decided just to stick to standard BOM.

It was a nice surprise mind!

The little green terminal blocks make things so easy to dissassemble and re-assemble!! They are made by Phoneix if anyone is interested :)

Once again thanks to Bo, Volker and people who answered my questions in the thread. My brother loves them, they really make a difference to his acoustic live!

Thanks, Matt
Title: Re: Bo Hansen DI layout
Post by: tagailog on February 15, 2016, 12:30:58 AM
good day,

I just wanted to ask, how can you connect an external 48V phantom power to this circuit? because my mixer does not have a phantom power so i need to make an external one.
Title: Re: Bo Hansen DI layout
Post by: Whoops on February 15, 2016, 01:16:54 PM
good day,

I just wanted to ask, how can you connect an external 48V phantom power to this circuit? because my mixer does not have a phantom power so i need to make an external one.

Maybe it could be simpler to you in that case to just use a passive DI, then you would not need the 48V.

Otherwise you can buy something like this:
http://www.thomann.de/pt/millenium_pp2b.htm

It will provide 48V phantom power to DI's or condenser microphones, probably it will be useful to you so you can also use condenser mics with your mixer you case you need that.

Title: Re: Bo Hansen DI layout
Post by: Treb on February 15, 2016, 01:59:54 PM
good day,

 i need to make an external one.

Do not make a 48 volt PSU yourself, buy one on ebay. Search for "cisco 48v psu".  Do not pay more than ~15 dollars/euros. These PSUs are generally capable of delivering 350-380mA. More than enough for this DI, as Bo says it only draws ~3.5mA.

I'm not exactly sure where to hookup 48 volts in the circuit so I'll let more knowledgeable people answer that question. You wouldn't want to burn down your house based on my uninformed advice...  ;)

Interesting stuff to watch:
https://www.youtube.com/watch?v=6McmnSmiY5o
https://www.youtube.com/watch?v=3w067lYc8Kw
Title: Re: Bo Hansen DI layout
Post by: Whoops on February 15, 2016, 06:11:40 PM
good day,

 i need to make an external one.

Do not make a 48 volt PSU yourself, buy one on ebay. Search for "cisco 48v psu".  Do not pay more than ~15 dollars/euros. These PSUs are generally capable of delivering 350-380mA. More than enough for this DI, as Bo says it only draws ~3.5mA.

I'm not exactly sure where to hookup 48 volts in the circuit so I'll let more knowledgeable people answer that question. You wouldn't want to burn down your house based on my uninformed advice...  ;)

Interesting stuff to watch:
https://www.youtube.com/watch?v=6McmnSmiY5o
https://www.youtube.com/watch?v=3w067lYc8Kw

Phantom power 48V is supplied to Pin2 and pin 3 of the XLR output connector of the DI.

as I've posted before the best solutions would be an external phantom power supply like this one:

http://www.thomann.de/pt/millenium_pp2b.htm

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 15, 2016, 06:22:47 PM
As Woops say, buy an external Phantom PSU, there are many good and inexpensive types/brands.

They are complete with balanced XLR connectors in/out and some of them can operate with both battery and 120/240 volts via adapter.

If you buy a two-channel version, then you have power for one more DI-box or a condenser microphone.

Another option is to make a simple modification and operate the DI-box from a 24 dc volts regulated/stabilized power supply.
50 mA (ore more) current capacity is enough for several DI boxes.

But it must be active stabilized, it is not enough with a regular guitar effect pedal psu.

The modification consists only to remove the two 6.8 k resistors and connect the stabilized 24 volt positive lead from the PSU to the now free end of the LED, (before thejunction of the two resistors) and the minus lead from psu to 100 uF minus side. (pc-card electronic ground)

--Bo--
Title: Re: Bo Hansen DI layout
Post by: tagailog on February 18, 2016, 07:43:43 AM
i think i need to buy and external PSU... thanks for the input guys...
Title: Re: Bo Hansen DI layout
Post by: Erazorblade on February 20, 2016, 09:19:45 AM
Hey guys,

I've got a question, maybe you can help me.
I recently build the DI with a Haufe transformer and the pcb available on the forum here but every guitar i plug in sounds distorted when hitting the strings harder, it seems the signal coming out in the end is too hot/loud. I checked the pcb, but on the first look everything seems to be OK. Is there anything i can check or something?

Thanks!

EDIT: Soldered everything again, but now the output is far too low...
Title: Re: Bo Hansen DI layout
Post by: Treb on February 21, 2016, 09:31:30 AM
Did you do the voltage checks? What are your readings?

input ground -> LED :  ? volts (should be +24 volts, +/- 1 volt)
input ground -> junction of 3,9k resistor etc. : ? volts (should be +12 volts, +/- 0,5 volt)


Title: Re: Bo Hansen DI layout
Post by: Erazorblade on February 23, 2016, 11:04:25 AM
When plugging in a guitar and playing, the output is really low. Need to push the preamp to maximum to even hear a signal (noisy).
Also the Amp-out is really low/not present.

Somehow when plugging in the guitar in the Amp-out i get a louder signal on the XLR-out than using the Input, but still far too low.

I checked again the voltages between

ground input and Jumper = 24V
ground input and 100nf capacitor=24V
ground input and left side of 3.9k Resistor=13V
ground input and emitter of BC560=13V

I opened the DI and made some pictures:

(http://www.bilder-upload.eu/upload/2419ea-1456243879.jpg)
http://www.bilder-upload.eu/upload/2419ea-1456243879.jpg

really dont know what to do know. Trying to fix it for 3 days now  :-\
Title: Re: Bo Hansen DI layout
Post by: Mondy on February 23, 2016, 11:55:09 AM
Hi Erazor

Cannot tell if you have added the wire link on the board if you are not using the LED indicator?

Also do you have your 1/4" jacks wired correctly?
Title: Re: Bo Hansen DI layout
Post by: Erazorblade on February 23, 2016, 12:18:43 PM
Hi Erazor

Cannot tell if you have added the wire link on the board if you are not using the LED indicator?

First of all thank you for the answer :)
I did not use a LED, i just used a normal wire.

(http://www.bilder-upload.eu/upload/89d8c2-1456248428.png)

Also do you have your 1/4" jacks wired correctly?

i am using the lumberg mono jacks.  After trying different things i ended up connecting the sleeve  to the ring to GROUND and the tip to +.

The ring usually is not needed here, but should not make any difference because on a normal instrument cable the ring=ground, or am I wrong?

(http://www.bilder-upload.eu/upload/249726-1456250123.png)
Title: Re: Bo Hansen DI layout
Post by: Treb on February 23, 2016, 01:09:18 PM
The input and output jack sockets must be isolated from the metal enclosure for the ground loop suppressor to function properly. Right now you have input and output grounds connected to the enclosure by the looks of it. Use plastic jack sockets to prevent this.

What's the tolerance of those two 6.8K resistors? That gold band usually means 5%, the BOM (and the PCB) specifies 1% for those two resistors.
Title: Re: Bo Hansen DI layout
Post by: Erazorblade on February 23, 2016, 02:26:30 PM
The input and output jack sockets must be isolated from the metal enclosure for the ground loop suppressor to function properly. Right now you have input and output grounds connected to the enclosure by the looks of it. Use plastic jack sockets to prevent this.

What's the tolerance of those two 6.8K resistors? That gold band usually means 5%, the BOM (and the PCB) specifies 1% for those two resistors.

Thanks for the answer Treb! :)

I now added the right Resistors with 1% tolerance and checked the voltages again.

For now I don't have any plastic jack sockets, but I tried to let my jack input&ouput hang out of the DI (not touching the housing), what - if I didn' t get you wrong - would be the same as having the plastic jacks in the DI.

Unfortunately everything stays the same...  ???
Title: Re: Bo Hansen DI layout
Post by: Treb on February 23, 2016, 04:57:21 PM
Your image hosting site is being blocked (potential malware etc.).  I suggest you first buy the proper plastic mono jacks sockets and hook them up per Bo's instructions. With regard to wiring, try to use different colour wires for ground and signal. Makes troubleshooting off of a picture much easier. How are your soldering skills? What does the solder side of the PCB look like? No solder bridges? Check the resistors, are the correct values in the correct locations? What transistors did you use?

Please DO read the techpage instructions Bo has so excellently compiled, follow those, work methodical and your DI should work flawlessly. Mine and many others' did. Good luck!
Title: Re: Bo Hansen DI layout
Post by: Erazorblade on February 25, 2016, 02:47:05 AM
Your image hosting site is being blocked (potential malware etc.).  I suggest you first buy the proper plastic mono jacks sockets and hook them up per Bo's instructions. With regard to wiring, try to use different colour wires for ground and signal. Makes troubleshooting off of a picture much easier. How are your soldering skills? What does the solder side of the PCB look like? No solder bridges? Check the resistors, are the correct values in the correct locations? What transistors did you use?

Please DO read the techpage instructions Bo has so excellently compiled, follow those, work methodical and your DI should work flawlessly. Mine and many others' did. Good luck!

Thank you for the answer Treb. Soldered everything again, checked BO's techpage carefully and added the plastic jack sockets. Seems to work fine now, only one last thing I noticed.

When i move my finger near/around the guitar pickups i can hear an increase of noise coming out of the DI.
When i touch the metal case with my other hand the noise is gone again.
When i touch the strings the noise is gone too.
When there is no guitar plugged in there is no noise at all.

Seems to be a grounding issue?

Title: Re: Bo Hansen DI layout
Post by: Treb on February 25, 2016, 03:46:03 AM
The noise issues you describe are normal. In an electric guitar (and bass) the strings are connected to ground, usually by a wire connected to the bridge. Just keep a hand on the strings to eliminate the noise.
Title: Re: Bo Hansen DI layout
Post by: Erazorblade on February 25, 2016, 12:25:50 PM
The noise issues you describe are normal. In an electric guitar (and bass) the strings are connected to ground, usually by a wire connected to the bridge. Just keep a hand on the strings to eliminate the noise.

ahh, yeah i see..
But in comparison to my Radial JDI it's noisier. I've read that this could be improved by shield the parts/cables?
Just out of curiosity.
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on March 21, 2016, 01:07:07 AM
Nope and I wasn't expecting them but thats what comes with the standard Mouser BOM from the first page of the thread...

I noticed you used some upgraded parts in yours but I'd already ordered the BOM and thought that the transformer would make the most difference anyway so decided just to stick to standard BOM.

It was a nice surprise mind!

The little green terminal blocks make things so easy to dissassemble and re-assemble!! They are made by Phoneix if anyone is interested :)

Once again thanks to Bo, Volker and people who answered my questions in the thread. My brother loves them, they really make a difference to his acoustic live!

Thanks, Matt


When I had first submitted a BOM for this project while waiting for my PCBs I wanted to give the option building these using the nice Vishay/Dale resistors and audio grade capacitors. The Vishay resistors are definitely bigger than the more standard looking one and I've had problems with them not fitting well on certain circuits. But they make you feel better using them since they are bigger, and from what I have read in all the trade magazines and in manufacturers ads, sound is all about feelings...


Paul
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 27, 2016, 05:02:22 AM
Erazorblade,

Did you manage to solve the problem with the DI-box ?

Potato Caces,

It is not necessary with extreme audio file resistors and capacitors in this construction, it is enough to use standard carbon or metal film resistors and plastic film capacitors, for example the red Wima capacitor, and Jamicon standard electrolyte capacitor.

But what is important are good transistor, such as Philips, Motorola, Fairchild, National, SGS /Ates.
Do not substitute unknown types and brands from China and the like, they can be noisy and weird in other ways.

The cables inside the DI-box housing does not need to be shielded, the only thing that is important is that the box cover is made of metal and is connected according to my instructions.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on March 27, 2016, 03:37:39 PM
Bo,

Yes, cheaper resistors and caps would be great, but I tend to go a little extreme when selecting components for projects. It's a bad habit.

By the way, I just got back from a tour where I was using your DI on bass and keys. The bass player was using mostly a pick and using a radial Pro DI, which are solidly built and does a pretty good job. However, there wasn't much of a comparison to your DI with the Sowter 9045. All the low end that one tends to miss when a bass player uses a pick was back and the clarity of the notes was exponentially better. I was able to keep the EQ on the bass pretty much flat, occasionally bumping the high mids if the PA or the room was being difficult. And I liked that the level difference from a passive DI wasn't extreme, making A/B comparisons much easier.

The DIs I used on keys had Cinemag CM-9711s. Before they were using a passive rackmount Radial product, which is also fine. But with a loud rock band, either the sample patches used or the keyboard itself would get buried and I could not really hear what was being played no matter how loud I turned it up during big musical parts. This was especially the case when she was just playing pads. Your DI with the Cinemags made a remarkable improvement. Keyboard parts cut through much better, and again much clearer and defined than before. In her IEM mix, she asked to turn the keys down since apparently she could hear her parts much better than before.

I've built about 8 of these so far, and I've still haven't had a chance to try out the ones I've made with Carnhill or Haufe transformers, but I can say that I have experience with many types of DIs on various sources during my time on the road and your design is best I've used. More importantly, the Sowter versions are helpful in convincing bass players to leave their Avalon U5's at home.

Thanks!

Paul
Title: Re: Bo Hansen DI layout
Post by: Erazorblade on April 13, 2016, 10:31:46 AM
BO

yeah i could solve the problem. Everything is fine now and I also built a second one without any problem. thanks!

I've got one question left, I would like to build a 3rd one and use a Transformer which adds a bit more low frequencies or attenuates the higher mids (for bass DI).
The first two DI-Boxes i built with a Haufe ST8456.
Will there be any tonal difference using the Lundahl LL1538?

If they are sounding the same but the Lundahl has just a bit more headroom, then I don't care and will use a Haufe again, since they are half the price and do an excellent job.
The best would be if anybody could deliver sound samples of the same guitar through different transformers?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 13, 2016, 01:08:11 PM
Erazoblade,

Haufe is very good, but Lundahl LL1538 have a ower all a bit better specs, and LL1538-XL have the best headroom in the low end.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Sinkia on April 27, 2016, 04:34:39 AM
Hey guys !
I have read until page 25 and then I post my question.. maybe the answer is in between p40..

I have a bunch of old API 2623-4, I was thinking : What can I do with those..

I had never thought to use it in this project, but why not..

Do you think it could work with it?

Cheers
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 27, 2016, 05:08:30 AM
Sinkia,

API 2623-4 is a low-ohm line output transformer with three 75 ohm windings, can be configured 1: 1/75 to two outputs of 75 Ohm or 1: 2/75 to 300 ohms or vice versa.

This is ideal as a line output transformer for discrete op-amps modules as API 2520 and John Hardy JE-990.

But it is unfortunately not possible to use as output transformer in this active DI box project.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Sinkia on April 27, 2016, 05:18:17 AM
Sinkia,

API 2623-4 is a low-ohm line output transformer with three 75 ohm windings, can be configured 1: 1/75 to two outputs of 75 Ohm or 1: 2/75 to 300 ohms or vice versa.

This is ideal as a line output transformer for discrete op-amps modules as API 2520 and John Hardy JE-990.

But it is unfortunately not possible to use as output transformer in this active DI box project.

--Bo

It was what I thought, but i had to ask first !  8)

So I guess I'll just make it with the lundahl or cinemag !

Many Thanks for your acknowledge !

Cheers
Title: Re: Bo Hansen DI layout
Post by: Sinkia on May 06, 2016, 07:47:49 AM
Hi there !

I come back again…


I really want to build some of this DIs..

Is this transformer is a good choice for this project ?

EA-10468 Mic Input Transformer
http://www.hairballaudio.com/catalog/parts-store/audio-transformers/ea-10468-mic-input-transformer

If not, could you maybe explain me on what point do I have to make my choice !

Thanks in advance !

Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on May 06, 2016, 03:41:52 PM
That one should work. It looks like it has the same impedance values as the Carnhill 9045, which is listed as an acceptable transformer on Bo's website. I've build a couple with the Carnhill's and I know they work great, so I don't know why the Ed Anderson version wouldn't be great as well.


Thanks!

Paul
Title: Re: Bo Hansen DI layout
Post by: Lagrange on July 06, 2016, 05:10:03 AM
It is unfortunate that Thomann moved their 10€ Millenium DI-E to a smaller box that (most likely) doesn't have enough room for the Bo's active DI:

http://www.thomann.de/fi/millenium_die_dibox_passiv.htm

But for passive DI's the 10 euros for the box and connectors is a good deal, and the new box is really nice and compact.  :)
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on July 06, 2016, 05:19:30 AM
The PCB is 80mm x 50mm.
The Box is 100mm x 130mm x 40mm.
Title: Re: Bo Hansen DI layout
Post by: Lagrange on July 06, 2016, 08:54:40 AM
The measuments would indeed say that it should fit, but I actually started thinking that the dimensions might be for the older, bigger box. Earlier in this thread there were pictures from a build into an older version, and it seemed that it was quite an exact fit there:

http://groupdiy.com/index.php?topic=36569.msg518811;topicseen#msg518811

Based on the pictures it would seem that the width of the older box could be the 100mm, and the new box is definitely smaller. I own both, but unfortunately I'm travelling at the moment, so I can't measure them. :/

But looking at the pictures on Thomann's website one can already deduce something about the width. The nuts on the Rean jacks are 17,5mm, and if the width of the box was 100mm, one would need to fit almost 6 of those side by side. That doesn't seem possible. Measuring from the picture it would seem that the width would more likely be slightly less than 80mm.
Title: Re: Bo Hansen DI layout
Post by: Lagrange on August 02, 2016, 12:26:29 PM
The dimensions of the millenium DI-E are roughly 90x75x35.
Title: Re: Bo Hansen DI layout
Post by: skovbakke on August 21, 2016, 05:08:51 AM
Potato Cakes

I'm building this as a bass DI and have been looking at specs for the different transformers. You seem to really like the Sowter and as far as I could see you initially chose it from having the most linear specs in the low end. The Lundahl 1538XL seems to be even better spec'ed though, or am I misreading something?
So I wondered if there were other reasons for preferring the Sowter?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 21, 2016, 09:51:38 AM
Potato Cakes,

When I built my prototype in the mid-1970s,  I used a Sowter 3678 microphone input transformer because I had a number of them on the shelf.
The only other option I had was very small Beyer, Sennheiser or Kemo, who could not stand much bass and had to high ratio.
At this time, there was not Lundahl transformers available to the public.

To day the Lundahl LL1538 or XL is the best for my DI-box design, it was no accident that I chose this when it came out on the market.

Before that, I used Lundahl LL1515 which was the predecessor of LL1538, and was the best mic transformer Lundahl made at the time.

Haufe ST8456 is also a very good, that fits my DI box very well.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on August 21, 2016, 05:07:14 PM
Hello, friends!

When I was building mine, I didn't have any Lundahl's with which to do any testing. If the 1538XL is spec'd better than the Sowter then definitely give them a go. I am using these boxes in a live setting, so the most testing I ever get is, "Does this sound better than the other thing I was using?" Either yes or no, then move on. There's not much time for tweaking or trying out multiple options. For me, the Sowter version is much clearer from top to bottom than anything any bass player to date has shown up with in their rig, and without all the distracting knobs and buttons that are necessary to be a hot seller at Guitar Center. I have built pairs of DIs with the Haufe, Cinemag, Sowter, Carnhill, and OEP, but I've only had a chance to really hear what the Sowter and Cinemag sound like on different sources through a PA, which again, has always been much more preferred than what was being used. Going with the 1538XL would be advantageous for the convenience of being able to directly mount it to the PCB, which will allow you to put it in a smaller enclosure. The Sowter required a bigger enclosure as you have to mount it off board, and the physical size of it is massive. Mr. Hansen definitely knows what he is doing and if he says Lundahl is best for his DI, then I would be inclined to believe it is the truth. Also, I bet you will find that the 1538XL is more readily available than a 9045. If I had to do it again, I would probably just use the Lundahl's, especially if it basically gives me the same if not better results, but I have this weird disorder where I do everything the hard way first.

At any rate, it's a great circuit, and again, many thanks to Mr. Hansen for sharing this with all of us!

Thanks!

Paul
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 21, 2016, 06:11:16 PM
Paul,

I'm sure there may be some special transformers from Jensen, Cinmag or Sowter that might have better performance than Lundahl LL1538, but these are physically much larger and also very expensive.

For example Sowter 9045 you mention, is a very good transformer, but it costs about 98 £/GBP, and it is almost double the price as LL1538.

Sowter produces very good transformers, and has a huge range of different types.
I use a lot of their transformers, but in situations where size does not matter.

Lundahl is one of the best in manufacturing transformers with a small convenient format, which many times exceed the performance of similar types from other manufacturers.
This is thanks to their own production of C-cores and winding technique.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on August 21, 2016, 09:06:55 PM
Bo,

Oh yes, those 9045s were not cheap. I definitely was not in a practical mindset when I was building your DIs. I saw the list of compatible transformers and wanted to build them all. However, when one tries to eat all the flavors of ice cream at once, it winds up giving you a tummy ache!

Thanks!

Paul
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on October 16, 2016, 02:29:45 PM
Hello, everyone!

I some of the guys I tour with have been asking me to build them some of these DIs as they are impressed at how much better they sound than what is typically seen on a guitar player's pedal board. LR Baggs, to be specific. The cases I have been using I think are slightly too big and I want to make some more in smaller cases. Could anyone here who has built a compact version share which enclosure(s) they used? The size I am referring to is the the Whirlwind IMP 2 or possibly smaller.

Thanks!

Paul
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on October 16, 2016, 03:46:51 PM
Paul,

The most compact box where the DI box all parts fit, is probably the "Deltron" box you can see on my tech page www.hansenaudio.se/techpage.htm
But it is slightly more complicated to assemble with spacers for the pc-card and some few things.

The other Hammond box on my tech page, is available in a lower version, where all the parts fit, and in that way it becomes much smoother.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on October 16, 2016, 07:22:12 PM
Thanks, Bo!

I didn't see that info at the bottom of the page. I'll mess around with both and see what I can come up with.

Thanks!

Paul
Title: Re: Bo Hansen DI layout
Post by: untune on November 11, 2016, 06:12:15 PM
I tried joining a few weeks ago to ask Bo a question but couldn't get my account here approved...  He kindly answered by email and in the meantime I built the DI vintage style, on tag board with quality components and Sowter transformer...
Title: Re: Bo Hansen DI layout
Post by: OhRats on February 19, 2017, 01:47:13 PM
Hi all,

I'm about to build the DI (waiting on PCB, and need to order a few more parts) and I have a few questions.

1.  Is there a good alternative to soldering the transfo directly onto the PCB?
I'll be using the OEP transfo.  So not too worried about damaging it.  But I'd be glad to have a straightforward way of swapping transfos in and out.  I will want to try out other transfos eventually, and I would be glad to have the option of going back and forth between them without building multiple boxes.

2.  I'm interested in using molex type connectors to connect the jacks and led to the PCB.  I'm not sure which specific ones fit the pcb, and which type is best for this kind of project.
The molex online catalogue is not exactly helping.. ;)
I normally solder jacks/leds to my boards.  But for this particular project I'd be glad to have a cleaner way of connecting/disconnecting the board and the box.)

Thanks a lot!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 19, 2017, 02:25:37 PM
OhRats,

The circuit board is specially made for this DI box, and built in such a way that everyone is able to mount the components on the easy and safe way.

The safest way to mount the transformer is on the board, there are exactly matching holes for all three transformer types.

The PCB solder connections are standard hole spacing, so there are many suitable connectors and screw terminals that can be used, but the best is to solder the wires directly onto the card.

--Bo


Title: Re: Bo Hansen DI layout
Post by: OhRats on February 20, 2017, 04:03:17 PM
Thanks so much Bo. 

Will follow your recommendations :)

Can't wait to put this together!
Title: Re: Bo Hansen DI layout
Post by: OhRats on February 28, 2017, 10:21:51 AM
1/4" Jack with break switch, like the ones produced by Cliff  (http://www.cliffuk.co.uk/products/jacksockets/s2.htm)(CL1160A)  or Neutrik (http://www.neutrik.com/en/audio/plugs-and-jacks/m-series/nmj4hc-s)
The good news is: they are cheap (http://www.eoo-bv.nl/index.php?_a=viewProd&productId=14158)!

Another noob question, apologies.  I understand I need to avoid a grounding connection between the TS jacks and the enclosure.  Following the above recommendation I got a neutrik NMJH4HC-S as a shorting input jack.  (Info on Neutrik Website: http://www.neutrik.com/en/audio/plugs-and-jacks/m-series/nmj4hc-s (http://www.neutrik.com/en/audio/plugs-and-jacks/m-series/nmj4hc-s)) (I now realize the NMJ4HF-S also allow for shorting. ) 

Issue is, the HC-S features a chrome nose - with plastic washers.  Unless I'm mistaken, it looks like with a male jack plugged into it, there is possibility for contact between the threads around the *barrel* of the nose and ground (with the male jack providing the connection between the ground lug and the barrel.) The contact point would be as pictured below.)

Am I wrong to assume that the chrome nose makes the part inappropriate for this DI box?  If so, is there a simple way to prevent the barrel from forming a connection with the aluminum enclosure?

Much thanks again!
Title: Re: Bo Hansen DI layout
Post by: rockinrob86 on February 28, 2017, 10:45:00 AM
I recommend ordering plastic cliff jacks for these - works perfectly in mine and they are good quality jacks - and it makes the grounding a no brainer.

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on February 28, 2017, 11:12:09 AM
OhRats,

Sure, Neutrik version works, but it is important that the insulation washers work properly.

Those jacks I recommend is Cliff Plastic, Type CL-1160-A, S2 BNB.

--Bo
Title: Re: Bo Hansen DI layout
Post by: OhRats on February 28, 2017, 12:34:52 PM
Bo, so it's worth at least testing the neutrik?  I'll drill the enclosure and mount the neutrik with its insulation washers, and test whether there is any connection between ground and enclosure with my multimeter.

Thanks so much for the replies!!
Title: Re: Bo Hansen DI layout
Post by: Whoops on February 28, 2017, 10:16:51 PM
Am I wrong to assume that the chrome nose makes the part inappropriate for this DI box?  If so, is there a simple way to prevent the barrel from forming a connection with the aluminum enclosure?

The chrome threads inside of the plastic barrel, so the outside part that will touch the metal hole is just the black plastic,
It's fine.

(https://www.banzaimusic.com/image.php?id=11860&type=D)
Title: Re: Bo Hansen DI layout
Post by: OhRats on March 04, 2017, 11:43:48 AM
I finished the assembly and the DI isn't working as expected.  The voltage tests are off.  Using a passive electric guitar, I'm also getting a lot of clipping through both outputs.  If I understand the circuit correctly, that would suggest that the clipping occurs before the transfo. 

Any pointers about what best steps to take to troubleshoot would be much appreciated. 


********

Here are the voltage test figures:

- 21.1 V at the link(led)/6.8k resistors junction.
- 9.4 V at the BC360 emitter/3.9k resistor/10uF+ junction.   

(I don't have a device with true 48v phantom power.  The above figures are from a device with 47.1v phantom power.  With a lower phantom power voltage (45v).  The 9.4v figure stays the same.  The voltage at the link changes a bit: 20.8v.)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 04, 2017, 01:02:23 PM
OhRats,

Have you built the DI-box on the original PC card or otherwise?

There are lots of people who have experienced similar problems here in this thread, when they got together the DI box for the first time, and of course there is something wrong they have done.

For example, turned a transistor wrong, using transistors with the wrong pin-out, or changed the location of NPN/PNP, wrong value of a resistor, reverse mounting of electrolytes or LED/diode, used an odd type of transformer which is connected wrong, etc.

So check your build again and again until you find the error, and please read the previous posts on this thread for more tipps about your problems.

Regarding your measured voltages.
My recommended voltage values ​​shall be reduced in the same propotion as your phantom power is less than 48 volts.

--Bo
Title: Re: Bo Hansen DI layout
Post by: OhRats on March 06, 2017, 09:33:43 PM
Hi Bo,

You were spot on.   When building it, I didn't notice the note on your page saying that 2n2904/2n2906 have a different leg order than BC550C/BC560C. 

With the 2N290x layed out correctly it sounds fantastic - and dead quiet, as others report.

Thanks for sharing your fantastic design and for your help! 
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 07, 2017, 03:09:18 AM
OhRats,

Nice to hear that you succeeded with your DI box.
Hope you will enjoy it.

--Bo
Title: Re: Bo Hansen DI layout
Post by: OhRats on March 14, 2017, 10:42:50 AM
Have been enjoying it every day since I built it!! :D
Title: Re: Bo Hansén DI layout
Post by: Whoops on April 13, 2017, 03:46:23 AM
Yeah it's a 125b size that i jb welded the screws and standoffs inside. Got it from pedalpartsplus.com for like $8.

I'm not sure why there's no ground issues but i like it. I'll finish my oep one tomorrow and post more sound clips

There's no ground issues with the setup that DI was tested.
Take it on the Road an soon the ground issues will appear.

Like Bo said many times, the isolated jacks are part of the circuit and are needed to made the ground loop suppression circuit work.

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 13, 2017, 04:33:04 AM
This DI box have a "practical and intelligent ground systems" which in most cases takes care of itself.

The metal box/casing is grounded in the XLR connector pin-1, which is the balanced signal ground system that goes to the mixer or mic preamp.

The DI-box input and output jacks that will be in contact with the guitar, keyboard, pedals and amps, who may have contact with each other via the signal ground and mains protective earth, is fairly well insulated through this DI box built-in "ground loop suppressor"

And for this reason, these jacks are of insulating plastic type, to be insulated from the metal housing, which is very important.
 
So in this case, a "ground lift switch" is not needed under normal circumstances, when ground/earth problems can arise in different situations on stage and in the studio.

Note!
The DI-box "ground loop suppressor" can of course not take care of grounding problems that occur between the guitar amplifier and effects, but will taking care of ground-loops that could arise between the guitar amp/effects via the DI-box and mixing console.


But, as already noted hear many times, it is important to follow my building instructions on my web site www.hansenaudio.se/techpage.htm
there you can find all the tips about good choice of jacks and the proper ways to ground the metal box and much more.

--Bo
Title: Re: Bo Hansén DI layout
Post by: Potato Cakes on April 13, 2017, 05:53:03 PM
There's no ground issues with the setup that DI was tested.
Take it on the Road an soon the ground issues will appear.

Like Bo said many times, the isolated jacks are part of the circuit and are needed to made the ground loop suppression circuit work.

I actually use these DIs exclusively on the road if I am mixing and for any TV show where my artist is performing  for the broadcast audio and I have never had an issue where I needed a ground lift. I've built these with Haufe, Sowter, Carnhill, and Cinemag transformers and all have noticeably if not significantly sounded superior to the usual assortment of DIs sent out with a mic package. If there was any sort of unwanted noise it was because of single coil pickups near moving light fixtures, which was minimal at best. If the grounding scheme is followed exactly as Bo said there shouldn't be any issue with the audio, although most back line techs I know blame the audio department for noises in their rigs...

Thanks!

Paul
Title: Re: Bo Hansen DI layout
Post by: pablobolche on April 13, 2017, 06:35:07 PM
This is my self etched Hanson DI...
I use it live and always good......
I use plastic jacks and have had no noise issues...
I use oep xfos without the can so my enclousure gets pretty small...11 cm x 6 cm x 3 cm

Thank You Bo!!!
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 14, 2017, 04:32:53 AM
pablobolche,

Very nice job.

Only one small thing.

Use the input jack "tip shorting brake switch" and connect this to the ground terminal on the input jack.

This ensures that not the input jacks are open when nothing is connected, and then prevents the buzz and hum.

This only applies to the input jack, not the output jack.

--Bo


Title: Re: Bo Hansen DI layout
Post by: pablobolche on April 14, 2017, 06:58:33 PM
pablobolche,

Very nice job.

Only one small thing.

Use the input jack "tip shorting brake switch" and connect this to the ground terminal on the input jack.

This ensures that not the input jacks are open when nothing is connected, and then prevents the buzz and hum.

This only applies to the input jack, not the output jack.

--Bo




Ok...you are right...thanks again.

Title: Re: Bo Hansen DI layout
Post by: Vac11 on June 11, 2017, 05:23:24 AM
Hello,

I have some troubles with my unit. When i plug the guitar i can hear loud buzz. I can hear some audio. When Is guitar disconnected no buzz.

Can you help me pleas?

M.
Title: Re: Bo Hansen DI layout
Post by: Vac11 on June 11, 2017, 05:25:08 AM
Pic 2
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 11, 2017, 06:58:12 AM
Vac11,

Of all the 100's of problems with this DIY DI box, I've responded to here, there has always been a wrong turn or wrong type of component or a connection error, probably in this case too.

In order to help you, I need to know more about your building.

1. I can see that you have made your own circuit board, have you checked that it is correct without interruptions and short circuits ?

2. What is the type of transistor, it's right pin-out, are they in the right place ?

3. How have you made the connections between PCB and connectors, can you view an image.

4. Have you checked all of the voltage points that I write on my construction description here:
www.hansenaudio.se/techpage.htm

5. I assume you use this DI box for a mixing console or preamp that has balanced microphone inout with 48 volts phantom power.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Vac11 on June 11, 2017, 11:13:58 AM
1. Yes, my board is self etched. I checked the traces against self etched files you have on your web. I think there is no short or missing trace.

2.  I  swaped the transistors for Fairchild bc550c and bc560c from 2520 DOA build. I checked transistor for proper direction. I think they are 100% ok now.

3. There is continuity between chassis, connector metal body and pin 1 on XLR ... I joined a separate "ground pin" on the XLR connector with pin 1. For 6.3 connectors i used Neutrik NMJ4HC-S . Maybe here is my problem. Im not sure if I wired those Neutriks correctly.
(http://img16.rajce.idnes.cz/d1603/12/12190/12190416_912a24f9ad17cfbf0b8d549e79b8d7a2/images/1_5.jpg?ver=0)

4. I will check voltages tomorow and will let you know.

5.  I used DI with my LaChapell 583 preamp. I think it has proper phantom voltage.

Thank you mr. Bo.

M.
Title: Re: Bo Hansen DI layout
Post by: Vac11 on June 11, 2017, 11:17:29 AM
Pic2
Title: Re: Bo Hansen DI layout
Post by: Treb on June 12, 2017, 07:40:07 AM
The black wire on the input needs to be on the other ground lug of the jack input.  Your input ground is disconnected when you plug in.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 12, 2017, 08:04:01 AM
Yes, Treb is right, ground on the input jack should be moved to the other side.

Everything else looks right.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Vac11 on June 12, 2017, 04:07:03 PM
Thank you Bo and Treb!

I think my first DI box is fully funkcional now. It sounds great!

I measured voltage:
There is 37V between PIN 1 and PIN 3, same between PIN 1 and PIN 2 on out XLR in the DI box.
There is 25.4V on junction 6k8 resistor and led.
Finaly there is 11.6V on junction 3k9 resistor and 10uF cap.

Thank you guys for help!

M.

Title: Re: Bo Hansen DI layout
Post by: Treb on June 12, 2017, 04:32:29 PM
Glad to be of help!
Title: Re: Bo Hansen DI layout
Post by: Fuzzz on June 30, 2017, 06:22:30 AM
Hi, I 've just finished one with OEP transformer and it sounds very good for me, better than my di input sound card so thank you Bo for sharing your work.

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 30, 2017, 06:35:39 AM
Fuzzz,

You are welcome.
 Nice you liked it, hope you will have a lot of joy with it in the future.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Newmarket on August 03, 2017, 11:40:58 AM
Hi. Thanks for all the input on this thread.
I bought an OEP262A3E transformer to give the design a spin.
Bit confused though as the OEP information on the
[urlhttp://www.hansenaudio.se/OEP%20A262A3E%20pin%20out.jpg][/url]
link shows a different model of transformer and the A262A3E pinout doesn't match what I can see on the pcb photos ?
Am I missing something ?
Thanks again.
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on August 03, 2017, 11:51:29 AM
I have never seen that OEP pinout from your link, looks totally wrong.
This one (http://www.oep.co.uk/page-content/datasheets/1440492525A262A3E%20issue%208.pdf) is used for the PCB.
Title: Re: Bo Hansen DI layout
Post by: Newmarket on August 03, 2017, 12:13:44 PM
I have never seen that OEP pinout from your link, looks totally wrong.
This one (http://www.oep.co.uk/page-content/datasheets/1440492525A262A3E%20issue%208.pdf) is used for the PCB.

Yes - the one you link to is what I have in front of me.
But the link I posted is from the BoHansen web page for the DI and seems to better match the pcb footprint I can see on the pcb layout images on the site too hence somewhat confused...
Title: Re: Bo Hansen DI layout
Post by: [silent:arts] on August 03, 2017, 12:25:44 PM
Which PCB layout you are referring to?
OEP is highlighted.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 03, 2017, 01:59:45 PM
Newmarket,

Both the old "Gustav/PC Grinder" and the new" Silent: Arts" PC board fit all three transformers.
There are three sets of holes for Lundahl LL1538, Haufe ST8456 and OEP A26A3E.

Both cards are visible on my DIY help page www.hansenaudio.se/techpage.htm

--Bo
Title: Re: Bo Hansen DI layout
Post by: Newmarket on August 04, 2017, 05:48:19 AM
Yes - I can understand multi footprints there now.
Think I got confused by the link for OEP detail from the webpage I linked to (not sure I'm doing the hyperlinks correctly here sorry)
http://www.hansenaudio.se/OEP%20A262A3E%20pin%20out.jpg (http://www.hansenaudio.se/OEP%20A262A3E%20pin%20out.jpg)
as it shows an OEP187A10E and not the A262A3E.

Thanks for the help and clarification.
Suppose I better build something now :-)
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 04, 2017, 06:16:05 AM
Newmarket,

Thank you for pointing this out.

I have not discovered that OEP's links have become strange, they must have changed on their website that I've linked to,

I'll fix this soon.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Newmarket on August 04, 2017, 07:18:50 AM
Yeah - links can often become an issue when the stuff gets rearranged / moved host.
While I'm being pedantic  ::) - the bottom line in paste from webpage below should presumably start BC560C ( rather than BC550C).

Thanks again

Here are some recommending European types that fits well:
BC550C = BC550B, BC549B/C, BC548B/C, BC547B/C, BC414B/C, BC337-25/40, BC237B/C, BC184B/C
BC550C = BC560B, BC559B/C, BC558B/C, BC557B/C, BC416B/C, BC327-25/40, BC307B/C, BC214B/C
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 04, 2017, 09:10:18 AM
Thank you,

Yes, you are absolutely right, will change it at the same time.

It gets easy wrong sometimes when there are many digit combinations at once.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Newmarket on August 04, 2017, 09:37:00 AM
It certainly is.
I have a hard disk full of specs and stuff here and a stack of (real) folders but part numbers with all the digits/letters and (often not relevant) suffixes can still get me going round in circles...
Cheers
Title: Re: Bo Hansen DI layout
Post by: providedrailroad on August 10, 2017, 01:31:33 PM
Does anyone have Gerber or Eagle files for this one, or some spare boards?

I'd like to build a couple but would like to have them manufactured or purchase the PCB's, I don't have a home etching setup right now and don't want to go down that road.

Thanks.

Wes
[email protected]
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 10, 2017, 01:42:43 PM
Wes,

You can order very nice DI-box PC-cards from  Silent:arts/Volker Mayer

http://groupdiy.com/index.php?topic=39570.msg488632#msg488632

--Bo
Title: Re: Bo Hansen DI layout
Post by: speed12 on August 14, 2017, 09:25:49 AM
Hi, First time replyer here but have been browsing this thread for a while.

Hopefully a simple question as a first post.

I'm in the process of designing a rack system to use with a guitar modeller and audio interface and as part of it would like a rack mounted DI. All of the commerical options seem to have either features I do not need or (mainly) the jacks in reverse of what I need (I'd like input jack on the rear, XLR on the front) and seem to cost a lot.

Having looked for a DIY option (I'm a competent solderer, but not 100% up to speed with actual electronic design - I can follow instructions though!) and found Bo's great DI box, my wondering is whether making this DI into a rack would be as simple as using mutliples of the PCBs constructed as normal? In my head it would work as long as I followed Bo's advice on grounding etc. As they are phantom powered then shared power supplies aren't an issue as far as I can see.

If anyone has any thoughts on potential issues of doing this or any helpful tips (specifically on making a 'rack' version) then they would be much appreciated!

Many thanks,
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 14, 2017, 11:30:13 AM
Hi Speed12,

Of course, you can mount several DI cards in the same housing without any problems.

But I do not really understand how you want to do with the voltage feed.

Are there regular balanced microphone inputs that you should use these DI boxes to, or is there any other type of inputs ?

Would you like to feed each card from the microphone input with phantom power, or do you want an internal rack power supply for all cards, so they not will be feed from phantom power ?

--Bo

Title: Re: Bo Hansen DI layout
Post by: speed12 on August 14, 2017, 12:07:01 PM
Hi Bo,
Thankyou for your swift reply!

My apologies - I worded the question badly. I will be using the DIs with a FoH mixer which can provide phantom power to each channel and that is how I am planning to power the units individually. What I was trying to say was that because of this there aren't any issues with sharing a power supply in the rack unit for the DIs which could cause noise issues.

It sounds as if it is all good to mount multiple units together so  I look forward to building them! Will report back with how it goes  :)
Title: Re: Bo Hansen DI layout
Post by: Treb on August 15, 2017, 03:59:03 AM
I've seen a few two-DI's-in-a-single-box here. Why not ask the makers of those for potential noise issues?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on August 15, 2017, 04:49:42 AM
Treb,

It's no problem to mount many DI boxes in the same housing if you do it right, it is equivalent to stacking many separate DI boxes on each other.

But it may be a problem with ground loops if many DI boxes in the same housing have an internal PSU, and if the DI boxes are to connected to many different instruments and preamps that are grounded in different wall sockets.

There are some DI boxes on the market that are two channels / stereo and some with even more channels that are good.

During the 1980's I was dealer  for EMO products here in Sweden , they had good simple passive DI boxes, and also had a 19 "rack that was able to screw both DI boxes and mic-split boxes on small panels/ modules.
A smooth and good system that I liked.

--Bo


Title: Re: Bo Hansen DI layout
Post by: kante1603 on August 15, 2017, 09:59:54 AM
I've seen a few two-DI's-in-a-single-box here. Why not ask the makers of those for potential noise issues?
Hello,


one of them was me.No issues at all.
As Bo already stated it is the same as stacking single units.Just take care of propper grounding and keep the jacks isolated where needed.


Best regards,


Udo.
Title: Re: Bo Hansen DI layout
Post by: jbvdwal on December 11, 2017, 06:50:16 PM
Just built mine, and it works great, still have to box it!

I did use some 50v 10uf elna silmic II's, and 1n4742 zeners, which i dont think are 0,5 w but 1,something.

I hope this does not affect the design? I can easily swap it anyway, put the zeners on sockets to be sure.

If not its getting boxed and probably used live on it first shows and festival allready <3
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on December 12, 2017, 04:35:12 AM
jbvdwal,

As I said many times here, this DI-box design works with almost component types and quality, and will work great.

The internal maximum voltage is 24 volts, so rated voltages for components higher than this are ok.

The recommended voltage and component values ​​are today's standard values, to give your DIY builder a benchmark when purchasing components.

Zenerdiides from 500mw to 1 watts are quite ok.

The type and brand of resistors/capasitors  is up to the builder's taste and conviction / belief.

Read ALWAYS building description and suggestions on my DIY page www.hansenaudio.se/techpage.htm, I have to try to explain all the questions you normally have regarding this project.

--Bo
Title: Re: Bo Hansen DI layout
Post by: jbvdwal on December 12, 2017, 06:58:18 AM
Had a re read and missed it indeed, sorry about that.
Thanks again for the design, and volker for the pcb! <3

Here's a little shoot out, with 2  guitar riffs (excuse the out of tune tele) between, the:

1: Bo Hansen DI
 2: LittleLabs Redeye,
3: the RME Di input on the soundcard.

https://www.dropbox.com/s/ytdnyk18aqibcro/DI%20TEST_BOHANSEN%20LITTLELABS%20RME.wav?dl=0

I didnt get all the people saying it has little output, mine is louder then the LittleLabs.

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on December 19, 2017, 06:00:34 PM
Amazing, we have passed 200,000 visitors.

I also want to take the opportunity to thank you for your great interest and that you like my DI-box design.

Wish you all a Merry Christmas & Happy New Year.

--Bo
Title: Re: Bo Hansen DI layout
Post by: andrii.konkov on March 27, 2018, 04:05:03 PM
I have a question concerning transformer ratio.
I could get my hands on vintage soviet input transformer. It has ratio 1:8 according to datasheet. Is it worth trying with this schematic? Also it could be connected in 1:15 ratio, maybe I'd better use it for passive DI box?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 27, 2018, 05:23:09 PM
Andrii,

A microphone transformer  that have a ratio of 1:8, connected backwards is ok, you get slightly lower output level approx.  -18 dB versus the 1: 5 original transformers around -15 dB.
(which is a suitable attenuation for an active DI box)

But 1:15 (that have aprox. 24 dB loss backwards)  fits better for a passive DI-box, and is nice for synthesizers and active instruments.

--Bo
Title: Re: Bo Hansen DI layout
Post by: andrii.konkov on March 28, 2018, 01:43:03 AM
Grateful for your reply. Then I'll  experiment with both i guess.
Title: Re: Bo Hansen DI layout
Post by: godwin on March 29, 2018, 03:29:50 PM
I'm looking for help on the Bo Hansen DI build. I have built four (4) of them. Three work excellent The fourth has a thin sound and low output from the XLR. I'm getting the correct voltages where the directions say to check for correct operation. Any help would be appreciated.
Title: Re: Bo Hansen DI layout
Post by: godwin on March 29, 2018, 03:43:08 PM
Pictures of my DI's. The cases are hand cut from stock aluminum tubing.
Title: Re: Bo Hansen DI layout
Post by: godwin on March 29, 2018, 03:55:47 PM
Another picture.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on March 30, 2018, 04:45:57 AM
Godwin,

I suppose you have already compared the three working PC cards with the PC card that is not working, that all components are in the right place, are correctly turned and have the correct value.
Also check all voltage test points, as I describe on my DI box DIY page www.hansenaudio.se/techpage.htm

If all this is ok then the next step will be to test if the unbalanced telejack output sounds right.

If it does, then there is something wrong with the Lundahl LL1538 output transformer, or its connection.

Try an additional time to solder all connection pins on the transformer.

NOTE, never cut the pins on a Lundhal transformer, after soldering, these pins are hollow and contain the transformer's thin leads from coils.

--Bo
Title: Re: Bo Hansen DI layout
Post by: godwin on March 31, 2018, 02:20:18 PM
Thank you for your reply. The unbalanced output DOES sound correct. I have another transformer on order. I will reply here after I swap it out.
Title: Re: Bo Hansen DI layout
Post by: musika on April 01, 2018, 11:13:43 AM
I really like your DI box made from thick aluminum rectangular tubing.  Can you tell me what the thickness is that you ordered?  What are the final dimensions and how much length of tubing is necessary to create one DI box?
Title: Re: Bo Hansen DI layout
Post by: godwin on April 02, 2018, 11:44:02 AM
All the tubing is 1/8" thick. The outer case is 2' x 4" x 6". The inner case is 2" x 5" x 3 & 3/4" The supplier cut the pieces to length .
6" long for the outer case and 3 & 3/4" for the inner case. I cut the top of the inner case  off with a hack saw at 1 & 3/4" then filed as needed until it slid inside the outer case. 5 #4-40 countersink 1/2" bolts mount the PC board and ground wire to the inner case.
2 #4-40 countersink 1/2" bolts secure the inner case from the bottom of the outer case. The inner case is tapped at #4-40 to receive those bolts. 

The aluminum is rough when received. I filed the edges square and smooth and polished the outside with fine sandpaper and steel wool.

I purchased the aluminum at Metals Depot online. The approximate case cost per DI Was $22.00.
Title: Re: Bo Hansen DI layout
Post by: godwin on April 02, 2018, 11:48:09 AM
Another picture.
Title: Re: Bo Hansen DI layout
Post by: godwin on April 02, 2018, 11:59:11 AM
Last one.
Title: Re: Bo Hansen DI layout
Post by: musika on April 02, 2018, 01:17:13 PM
Thanks for the info and additional pics...  you did some nice work with those and they look great!   
Title: Re: Bo Hansen DI layout
Post by: godwin on April 08, 2018, 10:33:10 AM
I replaced the LL1538 transformer with a new one and the unit is working correctly. Thank you for your guidance.
Title: Re: Bo Hansen DI layout
Post by: godwin on April 08, 2018, 10:40:10 AM
Added some labeling.
Title: Re: Bo Hansen DI layout
Post by: godwin on April 08, 2018, 10:41:12 AM
other side.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 08, 2018, 11:02:44 AM
Godwin,

Nice to hear that you solved the problem and that you like my DI box design.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Whoops on April 16, 2018, 11:32:03 AM
Hello Bo,
I would like to use your DI box circuit with Piezo pickups that need a much higher input impedance than electric guitars.

Could I change the input impedance of your DI box to 10 Megas?
What components should I change?

Thank you so much
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 16, 2018, 01:28:13 PM
Whoops,

Since the input starts with a BJT transistor, which draws some current on the base, you can not go as high as possible in impedance.

However, it is possible that it runs with a 10 Mohm bias resistor, as there is quite little current through this transistor, but I want to try and do some measurment on this for you and come back later.

It is also possible to replace the first NPN transistor and replace it with an N-channel JFET transistor, such as 2SK30, 170, 246, 2N3819 or 2N4391, 2N5457  series, and then only replace the 1 Mohms bias resistor to 10 Mohm or higher if desired, without having to change something else.

But even this I want to test for you, so everything works as it should.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Whoops on April 16, 2018, 02:44:53 PM


But even this I want to test for you, so everything works as it should.

--Bo

Hi Bo , thank you so much for your help and for caring.

actually having the option of 10Mega input impedance would even make this DI more flexible in terms of uses.

Thanks you
Title: Re: Bo Hansen DI layout
Post by: analogguru on April 16, 2018, 03:16:08 PM
This small modification should deliver you approx. the desired input impedance:
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 16, 2018, 03:42:00 PM
Whoops,

Sure, lots of choices and features are always fun, but jacks with "make and brake" functions, extra switches and potentiometers, cause poor contact and error over time.

So that's why I chose to present this DI-box design in its simple version, to always work and sound good.

Why did I choose an input impedance of only 1 Mohm, when almost all other active DI boxes have 10 Mohm.

Well, there are three reasons for this, one is that my original design from 1975 has this, the other is that BJT transistors are easier to get with good quality for all of you DIY people, and the third is that 90% of all guitar and bass amps have 1 Mohms input impedance, and then you'll recognize the sound characters and the behavior of your knobs on the guitar.

But wait a while, and I'll come back with some good suggestions for you.

Although I can guess and propose a modification, I'm careful about testing and measuring it, so I do not leave something by chance.
If I suggest something, I want it to work fully.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Whoops on April 16, 2018, 03:44:03 PM
Although I can guess and propose a modification, I'm careful about testing and measuring it, so I do not leave something by chance.
If I suggest something, I want it to work fully.


That's totally understandable and I appreciate that
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 16, 2018, 04:16:42 PM
Analogguru,

Yes, bootstrap from emitter to base bias ref. resitors, rise the input impedanse a lot, theoretically about 10 times, what I remember.

But it is also important to see how electronics behave after this modification in reality.

As an example, will the transistors' work point be correct and stable, so the output still clipping nicely with max headroom ?

--Bo
Title: Re: Bo Hansen DI layout
Post by: analogguru on April 16, 2018, 04:37:48 PM
.....
Yes, bootstrap from emitter to base bias ref. resistors, rise the input impedanse a lot, theoretically about 10 times, what I remember.
.....
Exactly - bootstrapping is an old (at least since the 50's) and well established technology.
Here is some easy-to-understand article about it:
http://www.hawestv.com/amp_projects/amp_hi_z_transistor/bootstrap-preamp.htm

.... will the transistors' work point be correct and stable,.....
The DC-"work point" of the transistor will not change with bootstrapping...

....  so the output still clipping nicely with max headroom ?
I doubt that anything clipping will be "nicely" (and I doubt that a piezo pickup will be able to drive this unity-gain-circut into clipping) - but why don't you just try it out if it fits your desires ?  It is only moving one leg of a capacitor from ground to the emitter (the already installed 1µF will be at least sufficient for lo-mid-frequencies and up)

BTW, I also doubt that it is really necessary to have an input impedance of 10M for a piezo pickup, especially when the pickup should have its on impedance converter [think about 5m cable from pickup to the DI-Box with 100pF/m {= 320kOhm @ 1kHz, 32kOhm @ 10kHz}], but....
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on April 16, 2018, 04:56:23 PM
After a couple of years of using this DI circuit with various transformer options, I now have a better opinion to share regarding the different possibilities.

Carnhill vtb9045- really shines on acoustic instruments that use a piezo pickup for live performances. There is drastic amount of clarity compared to the standard issue off-the-shelf options. Depending on the instrument and the environment, all that is required is a HPF and maybe some low mid cut.

Cinemag CM-9711 - I use this for anything that is a sample based instrument (keyboards, interfaces, drum machine, etc). For whatever reason, especially in a live environment, those type of sources are more easily heard in a thick live mix without the need to push them excessively loud. Typically for this application a passive Radial product (which are fine) is used, but when the dynamic of the music builds, things like keyboards tend to get lost, especially in a venue with subpar acoustics. This design plus the Cinemag seems to alleviate this problem. It even improves the clarity in IEM mixes and performers usually ask for less level due to being able to hear their sample based source better.

Sowter 9145 - If it is a bass, I only use this. It's the more expensive option and requires a larger case, but I have never had a bass guitar have as much clarity from the top to the bottom of its range with as little processing than with this DI configuration. It gets noticed with other bass players and engineers, which is really nice because it allows me to bypass all the Avalon and other gear that you typically see in a bass rig that cause problems more often then they should.

I have built versions with Haufe and OEP transformers, but compared to the ones mentioned above they do not seem to do anything special that would make them better than a passive Radial or some other similar product, but are more convenient as they have a footprint directly on the PCB. I built these with the components and construction methods exactly as prescribed in the assembly instructions, and all of them are noise free without the need for a ground lift. If there was noise it was because the source was generating it and not the DI. I have not found any need to tweak the circuit for different transformers or incoming impedance loads.

Two things that would be nice is for the PCB are to have a couple more options to directly mount different PCBs like JLM does with his Baby Animal preamp boards and a readily available compact enclosure option with engraved I/O labels. But as far as the circuit is concerned I think it is perfect. I definitely think it belongs among the ranks of other revered classic audio designs.

It would be interesting to see results of using different transistors and other components for the sake of science, but for those contemplating building some of these I would say don't bother with trying to figure out crazy modding schemes and to save that time and energy for other builds.

Brilliant work, Mr. Hansen. Thanks for sharing your brain with us DIY peasants.

Thanks!

Paul

Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 16, 2018, 06:15:03 PM
Paul,

Thank you for sharing your test results for different transformers, very interesting.

The types you mention as Carnhill VTB9045, the old Neve/Marinair mike-transformer workhorse, use to be a definite winner with its nice character.

And also Cinemag CM9711, (similar to Jensen JT13K7) with its wide bandwidth, low distortion, nice phase  and level headroom, is almost a theoretically completed perfect 5: 1 transformer.

But I'm curious about what you think about Lundahl LL1538 or 1538XL.

--Bo
Title: Re: Bo Hansen DI layout
Post by: Potato Cakes on April 16, 2018, 06:55:15 PM
Mr. Hansen,

I haven't built one with the Lundahl option. I initially went with Haufe's as it was reported how close they both were sonically in this circuit. I have about 10 boards left that I am going to use for something, so I may try the Lundahl's then. But as of right now I'm very happy with the ones I currently use, so further testing on my end is a low priority. Maybe that can be something to put on the list for later this year.

Thanks!

Paul
Title: Re: Bo Hansen DI layout
Post by: Mondy on April 22, 2018, 02:15:57 AM
Quote
Sowter 9145 - If it is a bass, I only use this

Any bass players use Bo's DI with the LL1538 transformer?

Whats your experience, do you need to up the transformer to LL1538XL or even the Sowter 9045 for good bass?
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on April 22, 2018, 04:32:12 PM
Today I am going to write something about DI-box transformers, regarding choice of type, character and quality.
I do it from my own point of view and experience.

My DI-box design is especially optimized for the Lundahl LL1538 or 1538XL.
It therefore performs very well when the balanced XLR output is loaded with a normal microphone input on a mixing console or preamp, that have a input impedance of about 1-2 kohm.
It is also capable of driving  very long cable lengths such as a multi-cable/stage box.

The other two options Haufe and OEP I have also tested, both practical and measurable, so I'm sure they can handle this too, but the LL1538 is still the best in all situations.

LL1538 is one of the best microphone input transformers in the world right now, along with some other types from Jensen and Cinemag.

Lundahl's dual coil structure and winding technology without bobin and their own core material production is unique, giving very high quality especially on small signal audio transformers.

Ok, now we talked about high quality with a great bandwidth, low distortion and high level capacity.

However,  there is another aspect of audio transformers, and sometimes it is a wish that they reproduce a special character for a particular purpose, such as for a bass guitar recording, and sometimes this does not have anything to do with "good quality", but more about music kind, production and taste, which is equally important.

Many times we think that older transformers made in the 1950s and 60s sound nice, such as UTC, Peerless, Stancor, Triad, Danish JS-Jørgen Schou and many others.

Unfortunately, microphone transformers from this time were mostly made for tube amps (low imp. to grid) and had high turns ratio around 1:15 to 1:30.

These types are not particularly suitable for active DI-box electronics, which are usually a unity gain impedance converter, and because these transformers can have a loss of -30 dB, the output becomes too weak to be an active DI-box.
A suitable useful loss from input to output for a active DI-box is about -15 dB.

So old high ratio microphone input transformer fit much better for passive DI-boxes, where you are used to weak output, and want it to be so.
For example, UTC type A10/LS10 or A12/LS12 has the reputation to sound great on some bass guitars.

Why these old transformers sound different and sometimes have a charming character, probably depends on the winding technology and core material from the past.
There are other guys in this forum who know this better than me, for example, "CJ" who has picked apart and analyzed more audio transformers than most of us.

Of course there are a lot of brands and types of microphone input transformers with ratio around 1:5 and 200 ohm to 5 kohm, that will work ok in my DI-box, and many of them are also great and also have more or less character,  but I have not tested all of them in same way as I did with Lundahl, Haufe and OEP.

 I have listed a number of possible types on my DIY page www.hansenaudio.se/techpage.htm and some I have tested, and some I have guessed are good for this application.

It's almost 15 years since my DI box design was published on this forum, when it was called ProdigyPro, and during this time, audio transformers have increased in their range in the market.

For a few years, a new caterogy of audio transformers has started to appear on the market.
These are microphone output transformers, where some types with lower turns ratio, are probably ideal for active solid state phantom powered DI-boxes.
But keep in mind, normally  these transformers are not encapsulated/shielded, so the DI-box case/box must be in metal, so the transformer does not pick up disturbing hum or buzz.

I have noted that Cinemag has some suitable types that are worth testing, according to the following types:

CMO-5/200-ct
CM-2422-H or L
CM-2461-nico
CM- 9711

Also noted that it sells some China-made microphone output transformer under different names, mostly copies of AKG and Neumann's well-known types.
How they are in quality, I have no idea, but I doubt that they can achieve the quality like Jensen, Cinemag, Lundahl, Sowter and  and some others with equal experience.

For the last 10 years I have served lots of China microphones, and those types that still have transformers, have not impressed me much.

--Bo
Title: Re: Bo Hansen DI layout
Post by: godwin on June 11, 2018, 11:17:04 PM
I cannot think of any advantage to making  a multichannel version of this DI.....but I made a couple anyway.
Title: Re: Bo Hansen DI layout
Post by: godwin on June 11, 2018, 11:18:18 PM
another picture.
Title: Re: Bo Hansen DI layout
Post by: godwin on June 11, 2018, 11:39:39 PM
The inside. I don't know why it's upside down. I tried three times. Sorry.
Title: Re: Bo Hansen DI layout
Post by: Bo Hansen on June 12, 2018, 02:30:24 AM
Godwin,

Very nice done.

Stereo DI-box It is useful to have for various synthesizer with multiple outputs and similar.

--Bo