Bo Hansen DI layout

[monkeyxx]

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.

 

[seba]

Hi, very good design.
I made two of them and then, I created an account on GroupDIY just to say : thank you

 

[Bo Hansen]

Seba,

Glad to hear that you like my DI box design.

--Bo

 

[GonzoConMojo]

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!

 

[Bo Hansen]

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

 

[Esoterimix]

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....

 

[GonzoConMojo]

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:

Thank you very much!

Cheers,
Bodo

 

[monkeyxx]

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.

 

[Bo Hansen]

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

 

[GonzoConMojo]

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

 

[monkeyxx]

Wooo!!  Glad to hear it.

Can't wait to build one myself!

 

[baol]

Hi, if I use the ll1538xl, must I change something in the schematic?
Thank you.
Andrea

 

[Bo Hansen]

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

 

[davide.bonetti]

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?

 

[Kir_For_Pleasure]

Tack Bo !

Grymt händig sak !

 

[Bo Hansen]

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

 

[Gearsix]

Hello, does anyone know if it possible to use an old A262A1E instead of A262A3E?

 

[Bo Hansen]

Gearsix,

No, sorry,  it is not usable for this application.

It's actually just A262A3E from OEP range that fit this DI box.

--Bo

 

[bds2020]

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/

Thanks, Brian

 

[Gearsix]

Thank you Bo