Einstein volume fading

[steppenwolf3080]

Hi guys!
I seem to have a problem with my Einstein...
I couldn't play it for some 3 weeks, as I was out of town. Now, I brought it home and played it at bedroom level when suddenly the volume faded to nearly zero and turned back to normal right after that.
I unplugged the guitar and listened to the "hum" of the amp caused by the unplugged floating cable and it still dropped once in a while. I turned all the knobs just in case a pot is dirty and let it on for half an hour. It didn't show the problem again...

Any ideas? I don't think it is the preamp as it did that in all channels...
Bias is healthy at 65mA

Best,
Stefan

 

[Ailean]

Try pulling the power tubes in pairs and see if one pair is ok and the other isn't. If both do it then at least you know it's not your power tubes.

I don't know the Einstein so I don't know which tubes are which but I'm sure it will be on the factory website.