amp works great ane the only issue is it is even a issue is when I turn the amp off I hear a pop in the speakers. I could have the volume tuned all the way down, switch to say phono (whicn I have nothing hooked up to and still hear jt?

Could this just be the nuture of the beast?

I took in to a trusted shop and they:
Recapped Power supply
Replaced diff amps ( both channels)
New bulb
Jacks cleaned
All pots deoxit
Speaker relay overhauled
Amp adjusted to factory spec

Am I worrying about nothing?