There should be muting transistors that kill the output when you shut it off but they may not work fast enough. Try running it off the switched outlet in your preamp/amp/receiver so it shuts off when the system shuts off. Or turn your amp off first. It is difficult to control what equipment does when you remove the power because; well, there's no power! Much easier to control turn on.
It does it only when I turn it on. Might be a bad cap across the switch.
I just notice that the pop noise occurs during all the inputs selected.
I just remove the cover and dont see anything unusual. What I did is I dioxit the contact switch and that did it.:thmbsp: Thanks for all the help.
BTW, while I had the cover off, I notice that PS cap use a Nichicon 10,000mfd. The rest of the caps on the board use Rudycon.