Dual CV80 - a couple of problems

[Solist]

Hi! Just when I was about to order new caps and resistors for the amp, it started to make problems.

First, when I touch the knobs you can hear static like noise through the speakers, does not happen on a regular basis.

Second, when I turn the amp off there is a quite noticeable pop. Never when I turn it on.

If any help, here is the service manual:

https://www.hifiengine.com/manual_library/dual/cv-80.shtml

EDIT:

The pop is instantenous (as soon as I turn the switch off), and it takes a couple more seconds for the speakers to go completely off.

 

[elnaldo]

I'd remove (and later replace with a modern X2 capacitor) any capacitor you see connected across the AC wires at the transformer tabs or at the power switch. The amplifier doesn't need this capacitor to work. It's there for noise suppresion but they age and can fail. They are connected to high AC voltage all the time.
Check my http://audiokarma.org/forums/index.php?threads/capacitor-explosion-i-know-you-like-this.748706/ pict links are down. I'll update them.

And clean the power switch.

Then recap the power supply.

And check for those noises each time.