Fuzz Pedal No Output – Only Hiss at High Volume Despite Clean Assembly and PCB

[Aria James]

I recently assembled a fuzz pedal on a custom PCB but I'm getting no audio output—only a faint hiss when the volume is high. During troubleshooting, I remembered this Proteus simulation guide for ultrasonic sensors, showing how audio signal paths and proper signal conditioning should work:

Introduction to HC-SR04 (Ultrasonic Sensor) - The Engineering Projects

A brief read on the Introduction to Ultrasonic Sensor HC-SR04. It is a sensor based on transmitter and receiver where former is used to send the waves...

www.theengineeringprojects.com

I also reviewed their detailed walkthrough on analog amplifier basics, which is very helpful for understanding gain stages, and I checked Electrosmash’s fuzz face analysis along with this Hackaday post on debugging DIY pedals. Has anyone faced a similar issue where the pedal seems wired correctly but output is essentially muted? Could there be subtle faults in grounding, coupling caps, or biasing that's preventing signal flow?

 

[JohnnyCreepy]

I’ve had problems with sockets making bad contact, pots with unreliable carbon tracks/contact and transistors cutting off. So yeah, subtle faults.

 

[BuddytheReow]

You'll need to provide some clear pictures of your build, front and back. There could be multiple things going on. Cold solder joint, wrong component value, wiring, transistor orientation, etc. We might see something you can't.