I'm working on breadboarding this amplifier circuit before transferring to a perf board.
When we power it from an adjustable DC power supply set to 12V, the audio output sounds clear. When we switch to a 12V 5Amp AC-DC adapter, we are getting almost nothing but noise.
We've already switched from one adapter which was providing an uneven output between 10V and 12V, to an adapter which we've measured at a constant 12.6V.
We're using the negative power terminal as our ground.
I would appreciate some suggestions for ways to troubleshoot this issue or any ideas as to why we're only getting clear sound from the adjustable power supply.