this has been going on for a while, my marshall jcm tsl has been having feedback problems a lot, even though i am playing it at about 3-4 every day or so for an hour or more.

but what im concerned about is even when i turn the volume on my guitar completely down, it will still have a bit of higher pitched feedback. its not necessarily loud, but loud enough to be annoying. im thinkign maybe a microphonic tube somewhere, but not sure

anyone have an idea what it may be? thanks
Sounds like a Microphonic preamp tube to me. Buy one and just plug it in until you find the culprit.
1987 Ibanez Jem 777LNG #124
2012 Herc Fede PMC Jem
1987 Ibanez RG550 Road Flare Red-R
Marshall JCM-1 W/Lead 12 Cab.
Wampler, Ibanez, MXR, Morley Pedals
alright that was what i was thinking, ill check it tomorrow when i get back to my drummers house. thanks everyone