Are all the tubes lit up? Take the tubes from one channel and but them in the other. Does the distortion move to the other channel? If so it is a tube that has gone bad. Then just go one by one until you find the tube. Be sure you unplug the preamp when you swap tubes.
How do i tell if i have a failed tube in my preamp?
Today after firing up system I noticed a distortion from all three drivers on one channel. Next I went from turn table to cd.Same thing,so I tried moving /wiggling all cables. No help or any change whatsoever.Could this be a tube going out in my BAT pre? Can I get an answer without a tear down please.I have extra tubes .6922s I believe.Thanks,R.W.