Pass labs poweramps

Is the popping coming from the unit or through your speakers. I have owned an x 250.5 for 11 years now and it will clink when it is warming up or cooling down. I think this is from the heat sinks expanding and contracting from the heating/cooling cycles of being off and on. It the sound is through the speakers then ya, a cap up the chain somewhere could be going or a tube

First l want to thank everyone for responding and l should not have said popping sounds actually it is clicking sounds l hear a few of then the unit stops. I have a trigger on it from my preamp so it stays in standby.

Popping is usually a sign of excess DC on the line
i experienced this recently with a tube amp .
get it checked out .
what model,  how old  is it.

I didnot read every response ,it went from popping to a clicking.
unless you know whatelse is in the chain   Impossible to give an accurate diagnosis.