SOLVED Vibrobot volume drop

[chinaski]

Hi all,
Just finished a Vibrobot build and it works, except for a marked volume drop.
I’m used to tremolo effect so I know it’s not a trick my ear is playing on me.
Is there maybe a resistor value that is more important than others as far as being out of spec or a change someplace in the circuit to make up for the drop?
Thanks in advance!

 

[Erik S]

The only resistor I can't see in your pic is R1 at lower left - should be 1m.

Is the fourth band yellow?

I didn't spot any errors in the ones I can see.

 

[jwin615]

Make sure vref is 1/2 Vcc.
Make sure you have no cold joints/reflow if needed.
Increasing R4 and R8 a little should add some volume but you don't want to add to much or you may clip the opamp.
But you should have a gain of 2.1 or so already.
Note, this pedal may not drive a long cable well due to no actives after the blend control. Maybe try a buffer/boss pedal after it if it's last in chain.

 

[Ale_jellybelly]

Have you calibrated the trimmer for the cleanest possible sound?
Another suggested fix is lifting pin 6 of IC3 but that might not do anything depending on your brand of IC

 

[chinaski]

Thanks for all of the help everyone!
As it turns out it just didn’t like the power supply I was using. I switched to a different one and the volume normalized.
After a little twist of the bias trimmer it sounds really good.