Bo Hansen DI layout

[Lee_M]

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.

 

[G-Sun]

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.

 

[Lee_M]

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?

 

[G-Sun]

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

 

[G-Sun]

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.

 

[Lee_M]

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.

 

[G-Sun]

Thanks!
Yes, here are some photos:
https://drive.google.com/folderview?id=0B2EgFUTJT9ZtfmlaYWM2X3BTSVc2T2NzeFVOR0pIZnZZOEgxYmFmcXJPeU9rX29OU29jVG8&usp=sharing

 

[Lee_M]

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!

 

[G-Sun]

Thanks!
I'll check your suggestions.

 

[G-Sun]

Are you getting any signal from the 1/4" monitor amp output?

No, nothing.

 

[G-Sun]

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)

 

[G-Sun]

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..

 

[Lee_M]

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?

 

[Lee_M]

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!

 

[Bo Hansen]

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

 

[G-Sun]

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.

 

[G-Sun]

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.
??

 

[Lee_M]

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... :-[

 

[G-Sun]

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)

 

[Bo Hansen]

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