New to Tube Amps/ Issues with Tube Amps

[WheatThins]

Hey,

So I picked up a Crate Vintage Club 50w 2x12, and when the Overdrive Channel is active I normally had the Gain set to about 8-9 for nice sounding distortion. Last week when I brought the volume to just under 2 the amp started to give really bad (high pitched) feedback even with the guitar volume down all the way. I am very new to tube amp troubleshooting and this problem only occurs when the Overdrive Channel is active... Could this be a preamp tube issue/power tube issue or something else?

 

[turk 182]

sounds like a severely microphonic preamp tube
with an oven mitt on lightly grip the suspected culprit if the feedback changes or stops you've found your problem
if not try to determine if the amp has been hot rod'd/modded in any way.