Bo Hansen DI layout

[buildafriend]

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?

 

[mulletchuck]

umm, isn't this thing powered by Phantom Power?

 

[Dylan W]

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).

 

[Bo Hansen]

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

 

[glbaudio]

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?

 

[Dylan W]

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).

 

[jonwormwood]

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.

 

[Matador]

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

 

[Bo Hansen]

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

 

[buildafriend]

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?

 

[heavyriderdiy]

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

 

[Bo Hansen]

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

 

[osso1001]

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

 

[Bo Hansen]

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

 

[osso1001]

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

 

[kante1603]

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.

 

[kante1603]

The guts:

 

[kante1603]

...and racked:

 

[useme2305]

why did you decide to make it get its 48v from the mic pre instead of the 48v rail?

 

[[silent:arts]]

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?