would it matter if i was using a different opamp than the listed one? (different tolerances) so far, im using a cheapo opamp to test if i did the soldering right.

finally finished the amp today. but i get really bad hissing. oddly, to fix the hissing i just disconnect the left/right channel output clip and touch it and the interference hissing goes away and im left with a perfectly clear connected channel and a humming disconnected channel. the moment i...