Little Green scream machine

Gt6371

Member
Hey everyone, so I finished my first build of the LGSM and I’m having some issues. I’ve done most of the mods that are out there. But when I go to half gain, or volume, it feels like I lose power. It’s gets fizzy and basically doesn’t sound good at all. Also, when I turn my guitar volume down from 9 and down, it just drops off to hardly anything. So basically the gain, the volume on the pedal and guitar have to be on 10 to sound decent. Any help would be appreciated. Thanks.
 
By the description, I get the impression the VREF may be off. I'd dbl-check the voltages and ensure that VCC is at ~9v and that the VREF (junction of R16, R17 & C10 - or lug #1 of the Volume pot) is at ~4.5v

If the VCC and VREF correct, make sure they are reaching their appropriate destinations. VCC should be on pin #8 of the opamp and the collectors of both Q1 & Q2. VREF can be checked across the PCB by cross matching with the schematic.

Other than that, we will need good clear photos of both sides of the PCB.
 
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