PS-100 gives a "pop" after few minutes and after which volume is significantly dampened

Stage & Studio Power Station PS-100
4

Hi Jekill,

Unfortunately, Fryette has a 90-day warranty on tubes. Given that the unit has two power tubes and they tend to fail more often, yes, I would start with those.

See here for tube recommendations, What 6550s do you recommend?

Regards,

Dan