u/BigKob45

I plugged my distortion guitar pedal (Metal Muff) to an amp and noticed that the volume of the clean channel was much higher than with the pedal on. I still had distortion but I had to crank it to max on the pedal volume knob to make it louder, but at this point the audio feedback was unbearable.

I got my multimeter and got to work. I noticed the pin 5 on U4 opamp was at a significantly lower voltage than than the rest of this opamp pins, specifically pin 6. My power supply is a 9V DC and I did not use a battery. Is this an automatic red flag or not?

Is there anytjing more I can do in terms of DC domain measurements or should I find someone with an oscilloscope to look into it?