I know there was a how long to Mesa Boogie tubes last this past week. I have a specific question. My Mesa Boogie Express 5:25 periodically cuts out with volume fading out over about 10 seconds. Switching the amp into standby for 30 seconds and switching it back restores output. I tipped the amp when it faded this morning and it looks like one of the EL-84 power tubes was red plated. Tubes are cheap enough from Sweetwater. I can probably get matched EL-84 tubes locally but I'm not sure they'd be Mesa Boogie tubes. My two are, will I damage the amp if I continue to use it by switching it to standby and back? Is red plating caused by a failing tube or something else? Mesa Boogie amps are fixed bias amps. How careful do I need to be about replacement tubes? I'll really appreciate hearing from someone who knows for sure. Internet searches bring up too much contradictory information from sources of unknown provenance.