Re: Bo Hansén DI layout
« Reply #60 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?


dissonantstring

Re: Bo Hansén DI layout
« Reply #61 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/

there are many alternatives, you just have to find the right one and it depends on your taste.
regards,
grant

Re: Bo Hansén DI layout
« Reply #62 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?

mulletchuck

Re: Bo Hansén DI layout
« Reply #63 on: February 22, 2010, 05:00:07 AM »
has this PCB been made available for purchase?    this looks like a great first project!
www.youtube.com/mulletchuck for all my recordings

Soeren_DK

Re: Bo Hansén DI layout
« Reply #64 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
Quote from: idylldon
...it works like a champ and is as quiet as a mouse pissing on a cotton ball.

http://www.soundcloud.com/doctorsclub

Bo Hansen

Re: Bo Hansén DI layout
« Reply #65 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
I met a man with a dollar, we exchanged dollars, I still had a dollar.
I met a man with an idea, we exchanged ideas, now we each had two ideas.

justanalogue

Re: Bo Hansén DI layout
« Reply #66 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.

mulletchuck

Re: Bo Hansén DI layout
« Reply #67 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!
« Last Edit: February 22, 2010, 09:11:19 PM by mulletchuck »
www.youtube.com/mulletchuck for all my recordings

juanjovincenzo

Re: Bo Hansén DI layout
« Reply #68 on: February 22, 2010, 09:52:12 PM »
Really Thanks Bo and Soren!!!!
Muchas muchas gracias esa es la manera!!! :D
Best Regards
Recorder and Mixer

Re: Bo Hansén DI layout
« Reply #69 on: February 22, 2010, 11:50:39 PM »
I'm looking forward to this very much!  ;D





Bo Hansen

Re: Bo Hansén DI layout
« Reply #70 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
I met a man with a dollar, we exchanged dollars, I still had a dollar.
I met a man with an idea, we exchanged ideas, now we each had two ideas.

mulletchuck

Re: Bo Hansén DI layout
« Reply #71 on: February 23, 2010, 04:48:01 PM »
so are we ever closer to seeing a DIY kit for this?  ;D ;D ;D
www.youtube.com/mulletchuck for all my recordings

justanalogue

Re: Bo Hansén DI layout
« Reply #72 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.

rotation

Re: Bo Hansén DI layout
« Reply #73 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


flaheu

Re: Bo Hansén DI layout
« Reply #74 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
As MagnetoSound said:
"Sad lack of balls in today's bands, IMO"

rotation

Re: Bo Hansén DI layout
« Reply #75 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

Re: Bo Hansén DI layout
« Reply #76 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
« Last Edit: February 24, 2010, 12:17:27 PM by chrispbass »

Bo Hansen

Re: Bo Hansén DI layout
« Reply #77 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

« Last Edit: February 24, 2010, 09:59:21 PM by Bo Hansén »
I met a man with a dollar, we exchanged dollars, I still had a dollar.
I met a man with an idea, we exchanged ideas, now we each had two ideas.

flaheu

Re: Bo Hansén DI layout
« Reply #78 on: February 25, 2010, 07:18:40 AM »
Thanks your reply.
i will try your suggestions.

Cheers
As MagnetoSound said:
"Sad lack of balls in today's bands, IMO"

Re: Bo Hansén DI layout
« Reply #79 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
« Last Edit: February 25, 2010, 12:22:54 PM by chrispbass »


 

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