Crackly noises from DB750
I'm getting intermitttent staticky crackly noises from my DB750.
It doesn't matter if anything is plugged in. Not terribly loud, but annoying and disturbing
Turning the preamp gain down does not help, it seems to be the power amp making the crackling.
The amp is pretty new, and I haven't played it that much (mostly low-volume practicing by myself).
Does this sound like bad tubes? I noticed a while back that they were a bit microphonic (when I tap the front plate I hear a bit of glassy ringing coming through the amp).