Coloursound inductor less wah: no signal

[edo1123]

Hi guys, I've tried to build this pedal following the layout on tagboard. It seemed to be an easy board, but I've built it twice and I have the same problem. I checked the offboard connection and there shouldn't be any mistakes. I took the voltages:
C: 8.63
B: 0.69
E: 0.0
It does nothing. When I turn it on I can only hear the noise of the power supply (I guess). I really don't know what it could be because I've built it twice and I've made the same mistake.

[induction]

If you post some pictures of the board (high-resolution, front and back) and offboard wiring, maybe we'll spot something.

[edo1123]

image818.jpeg
image81.jpeg
I'm sorry, but it's the highest resolution I can get. The only change is the substitution of the 47k with a jumper.

[induction]

Sorry, I can't make out much from those pictures. The transistor looks reversed, but it's hard to say anything for sure.

If you can get some higher resolution pics, I may be able to help.

[edo1123]

You were right about the transistor, but it was the jumper too.. I mean, in some way the jumper I put instead of the 47k resistor was cutting the signal.. I've removed it and now it works.. I saw someone putting a resonant potentiometer.. Where it should be placed if wanted to add one?

[induction]

edo1123 wrote

in some way the jumper I put instead of the 47k resistor was cutting the signal.. I've removed it and now it works..

I assume you put the 47k back in? The jumper should have made it louder. Maybe the jumper was broken inside the sleeve or something. In any case, unless it's too quiet, it should be fine with the 47k.

I saw someone putting a resonant potentiometer.. Where it should be placed if wanted to add one?

Replace the 33k with lugs 2 and 3 of a 50k pot wired as a variable resistor (lug 1 can be connected to lug 2, or it can be unconnected). Resonance will increase as you turn up the pot.

[edo1123]

I've tried another jumper, but it's the same.. If I remove the jumper it works and I saw on tagboard someone putting a 151k resistor and almost get the unity gain. Maybe bigger the resistor louder the sound? With no resistor I get over the unity..
P.s. The resonance mod worked really well. Thanks, mate

[induction]

edo1123 wrote

Maybe bigger the resistor louder the sound? With no resistor I get over the unity..

You're right. I looked at it again, and I had misread the layout. That resistor is in parallel with the output, so the larger the resistor, the higher the volume. (I thought it was inline with the output, where it would behave the opposite.) For maximum volume, you'd remove that resistor entirely.

Glad you got it working despite my mistake. Good job.