Help with DBA Reverb Clone with Feedback mod

grobbins

grobbins

Member
Hi Everyone,

I hope this is the right forum. Apologies if not. Ive run into a bit of trouble with a pcb design. Its based of the DBA Reverberation machine but with the feedback mod.

Unfortunately my PCBs dont work, which is a real shame as id had a great run before this. I used eagle and JLC. Bypass signal all good, when activating the effect there's silence. When hitting the feedback you can hear it very quietly, and the vol and feedback pots affect this. I have reflowed everything so i think soldering is all good.

Would anyone be able to see if they can spot any issues here please ? below is my schematic(first image), top and bottom layers and then the schematic(last image) I based it on.
Sd Schem.png

sd board.png
sd top.png
sd bottom.png
og schem .png

Cheers all, have a nice weekend.
 
Nothing aside from R16/C11 seeming odd, but it's DBA so grain of salt there.
What debugging steps have you taken thus far?
Audio probe the outputs of the opamps?
Check the 78L05 pinout/output? Iirc, there are reverse pinout versions for some reason.
 
jwin615 said:
Wait, isn't IC1B feedback tied to ground?
Gain pot is missing connection
Knew something looked off
Click to expand...
Ahh how annoying! Good spot thank you very much. I'm very dyslexic so these things are hard for me to spot. I could do a jumper wire to r22 from lug 2 of gain then?
 
jwin615 said:
Output stage from 2 other Brand's build docs for this pedal
I think R22(your schem) is an issue too. But it may not be. Having trouble flipping back and forth on mobile.
Click to expand...
Used a jumper from the middle pin to r22 and we're in business baby. Thanks so much for your help.

This is such a silly pedal!
 
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