Boss FZ-2 Hyper Fuzz Noise question

[jimitrader]

https://effectslayouts.blogspot.com/2020/05/boss-fz-2-hyper-fuzz.html
I built this cool fuzz pedal and its working only there is some noise ..it seems to get worse if i turn the guitar vol knob down a little? is this a common problem that is easily fixed? thanks for any advice