Barber Dirty Bomb build being very weird

[Tom Lauten]

I'm building a Barber Dirty Bomb from guitar fx layouts..

http://tagboardeffects.blogspot.co.uk/2012/10/barber-dirty-bomb.html?showComment=1422619687944



All built up with only one real change a 120pf cap changed for a 100pf

I have checked battery and tracks for shorts etc but when I plug my guitar in all I get is a clean signal! That's with or WITHOUT the board being powered! I'm going mental here!






HEEEEELP!

[GibsonGM]

Have you hooked it up to a bypass switch?

If so, that suggests a short in your switch wiring.

If not, it suggests a short between in/out on your PCB.

If neither of these, read the "Debugging" page and get some info up, it's a sticky at the top of the forum.  Without an actual schematic, I don't have enough time to trace thru and see if this is wired right.  The fact you're getting signal with no power to the board suggests there is a short between in/out....jumped a track, so to speak

[deadastronaut]

tip, ALWAYS test your builds work BEFORE you add the footswitch/box it...

just one less thing to debug ok..


to test, hook it up to power, ground, (use a breadboard/ or croc clips) in/out...all grounds joined..

if it works, box it up with the switch/led . 

[Tom Lauten]

No foot switch.

Everything is hard wired into the circuit.

I have checked all of the traces with a magnifying glass...no shorts. If there are any shorts between in and out, it's in the circuit somewhere...or my layout.

I found a schematic (below) but I don't know if it's for this version....I only had the vero to work from. The guy who did the vero has done many and it seems people have had it working without issue.

Some of the tone controls seem to have a very minor effect and touching various points in the circuit results in crackle so the signal is going through at least some of it to the output.

[samhay]

If the ground on the board is not connected then you have continuity from In to Out via the 1M and 100k pull-down resistor in series. How do you have ground connected at the moment?

[Tom Lauten]

Right now the ground on the board is the neg input off the battery...third input lead up on the left hand side of the vero.

[slacker]

Have you also got the sleeves of the input and output jack connected to the board ground?

[Tom Lauten]

When the sleeves of the jacks are connected to the neg battery terminal (ground) the circuit is silent.

[PRR]

> When the sleeves of the jacks are connected to the neg battery terminal (ground) the circuit is silent.

They really have to be connected that way.

Question is: why is it silent?

Check all opamp output pins for +4.5V DC.

Use a signal tracer and find where the signal is lost.