This circuit, designed as a bass scream, keeps generating a low noise about the same loudness as the guitar signal on the output.
You have a feedback through the wet-dry circuit. That's an oscillator. The dry signal should have a buffer amp before it's fed to the wet-dry balance pot. It very likely would stop the signal going from output back to the input.
Others have already said there's no decoupling capacitors in the DC supply inputs of the opamps. That is a common unwanted feedback mechanism (=through the power rails) and can cause oscillation.
Here's one way to break that feedback path through the wet/dry mixer. I found this recently when reverse-engineering a powered speaker for a friend. Since the wiper of the pot is connected to ground, and the input to the opamp is held at "virtual ground", there is no signal path between the two inputs.