Acrylic Overdrive - no sound

[Flashheart]

Building the Acrylic OD and the pedal lights up but no sound when pedal is on. I checked the transistors and they’re good. Any idea what I’m missing?

Hopefully you can see the image.

 

[spi]

Is it just me, or does it look like your input signal from the jack is also going to ground (looks like a wire going to the - input on the board)?

UPDATE: Nevermind, I think the wire is just running underneath the jack. At first, it looked like two wires coming off the jack.

Did you get the transistors biased?

 

[Flashheart]

It’s tough to see but I have the ground wire going to the ground of the board and the live going to the footswitch.

 

[Big Monk]

We need clearer pictures and we need to see the underside of the board.

 

[Flashheart]

I’ll get better pictures and also one of under the board

 

[Coda]

Have you adjusted the trimpots?

 

[Flashheart]

Yep. I adjusted the trim pots and still no response.

 

[ChrsGuit]

Have you adjusted the trimpots?

Just curious (as I am about to start this build myself) if there is a default trim pot setting or how one goes about that. I checked the documentation and found nothing that stood out explanation-wise

 

[jimilee]

Just curious (as I am about to start this build myself) if there is a default trim pot setting or how one goes about that. I checked the documentation and found nothing that stood out explanation-wise

I set mine at about 4.5v you might be able to go as high as 5v. Typically I call t, it’s half of vcc.

 

[ChrsGuit]

I set mine at about 4.5v you might be able to go as high as 5v. Typically I call t, it’s half of vcc.

Awesome. that gets me in the ballpark. I'm guessing that's equal bias across all three trim pots and test at ?

I set mine at about 4.5v you might be able to go as high as 5v. Typically I call t, it’s half of vcc.

So, given my limited knowledge of circuitry (this is only my second time dealing with bias pots, I can assume I need to test for proper voltage bias at the collector leg of the J201's, as the biased voltage directly supplies each of them?
The only other time I've had to bias a pedal was an out of spec treble booster that had an actual dedicated test pad incorporated into the pcb.

 

[jimilee]

Awesome. that gets me in the ballpark. I'm guessing that's equal bias across all three trim pots and test at ?

So, given my limited knowledge of circuitry (this is only my second time dealing with bias pots, I can assume I need to test for proper voltage bias at the collector leg of the J201's, as the biased voltage directly supplies each of them?
The only other time I've had to bias a pedal was an out of spec treble booster that had an actual dedicated test pad incorporated into the pcb.

Yessir, you got it.

 

[swelchy]

theres something funky with your jack wiring

 

[ChrsGuit]

Yessir, you got it.

Thank you sir! Much appreciated!

 

[Fama]

theres something funky with your jack wiring

I thought so too at first, but I think it's just the power jack wires that look weird from that angle (plus they're all black so they mix up). At first I thought the output jack also went to ground or something, but it's the power jack wire that just comes out from right under the output jack.

Unless you mean the actual lugs on those jacks, since I don't know how those work on those specific jacks, I have never used them. But I think if bypass signal works then the in/out jacks should be correctly wired?

 

[Barry]

I thought so too at first, but I think it's just the power jack wires that look weird from that angle (plus they're all black so they mix up). At first I thought the output jack also went to ground or something, but it's the power jack wire that just comes out from right under the output jack.

Unless you mean the actual lugs on those jacks, since I don't know how those work on those specific jacks, I have never used them. But I think if bypass signal works then the in/out jacks should be correctly wired?

It could bypass signal and be wired wrong with those jacks.

 

[music6000]

theres something funky with your jack wiring

Am I missing something here as the only picture I see is at the top, Flashheart from Nov.2 - 2021!???
This is not a current Troubleshoot discussion, it's about Bias voltage on the Trimpots for a future Build.

 

[swelchy]

Am I missing something here as the only picture I see is at the top, Flashheart from Nov.2 - 2021!???
This is not a current Troubleshoot discussion, it's about Bias voltage on the Trimpots for a future Build.

I was apparently high