Bo Hansen DI layout

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

Bo Hansen said:

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

Click to expand...

Ok...you are right...thanks again.

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.

Pic 2

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

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.


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.

Pic2

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.

Yes, Treb is right, ground on the input jack should be moved to the other side.

Everything else looks right.

--Bo

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.

Glad to be of help!

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.

Fuzzz,

You are welcome.
Nice you liked it, hope you will have a lot of joy with it in the future.

--Bo

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.

I have never seen that OEP pinout from your link, looks totally wrong.
This one is used for the PCB.

[silent:arts] said:

I have never seen that OEP pinout from your link, looks totally wrong.
This one is used for the PCB.

Click to expand...

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...

Which PCB layout you are referring to?
OEP is highlighted.

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

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
as it shows an OEP187A10E and not the A262A3E.

Thanks for the help and clarification.
Suppose I better build something now

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