new (I think) "soft" pop when standby switch turned on

[Bern1]

in my recently built Metro JTM45.

I built the amp without the 5.6 resistors, got the big squeal when closing the standby circuit, then installed the resistors. The squealing stopped and (I thought) it became dead silent when flipping the switch. Somehow in the last week after I turn the amp on, I wait a few minutes, sometimes more if I get sidetracked, then I turn the standby switch on. When I do that I get a slight but audible "thump".

Maybe it was doing this the whole time? Maybe this is normal and I'm being weird about my new amp?

Hmm, just went to power on my Z Route 66 using the same procedure and it made no thump at all, dead quiet....

Volume at about 1 o'clock on both amps.

Thanks for any thoughts!

Bernie

[PCollen]

I was having a similar issue with my JTM45 clone, except when placing the amp in STBY before turning the MAINS OFF when powering down the amp .
I removed the 0.047uF/600V cap between the rectifier and the STBY switch and the "problem" disappeared, never to return. Now, my amp powers ON or OFF with no pops/thumps.

[Bern1]

ok thanks, I'll check what happens when I power off.