Decadence Preamp Volume Issue

[booby_hill]

Hey y’all! Just finished up this pedal and while it sounds great, when it’s engaged, the volume isn’t at unity; even with the pre and post maxed out. Is that normal? I know somebody on here said to change out R11 for 120K. Is that all that’s needed? Just wanted to see if there’s any other values that I should be worried about. Thanks I’m advance!

 

[finebyfine]

I’ve built 3, one stock and 2 replacing R18 (33K) with a 150K resistor which is what Rob suggested and the volume is much better with that. Stock I was getting unity gain at 3 o clock and with the substitute its around 1

 

[temol]

Yes, that's normal.
Look at the schematic. However large the signal comes in, the diodes clip to 0.6V peak (1.2V p-p). Then: R20 plus potentiometer - it's a voltage divider. Signal drops below 0.2V peak (0.4 p-p). And it's with potentiometer maxed. With potentiometer @ noon it's around 90mV peak.

 

[music6000]

Do not refer to the Picture on the Main Page, that is just a render showing R11.
R18 stock is 33K, Increasing it to 150K raises the overall output. The BOM Page shows the correct R18 - 33K.


This is the Current PCB:

 

[booby_hill]

Thanks for all the info, guys! I’ll be sure to change that over tonight, and then hopefully the issue will be resolved!