Hey guys, I know this may seem like a stupid topic to start, but this problem has seriously been haunting me for years. My tube amps always turn tubes microphonic- it used to always be with my crate v30 (a great little american made class A el84 combo I bought for $300) but it was a hotbox and the tubes were placed right over the speaker... it turned tubes microphonic left and right. Now I've had the problem again as of recent. There is this rattling sound in my amp on certain noises- i'm almost positive its a microphonic tube, but I cannot figure out which ones are microphonic and I've tried many combinations of my collection of 12 preamp tubes consisting of tung sol, mullard, jj, sovtek reissues- and recently I bought some nice NOS tubes from KCA tubes. RCA triple mica black plate 5751, 80's jan 5751, and a sylvania 7025- i also have a nos jan philips 12ax7wa, nos jan philips 12at7 (not a very good tube at all- all the big tube stores are selling em for $10), i also have two unidentified "USA" 7025's with nice looking internal stucture... along with my reissue tubes I cannot for the life of me figure out which ones are microphonic. Could this be something else? I've had noise from a loosely connected filter cap before that didnt sound anything like this. I've changed power tubes and rectifer tube, I've resoldered all sorts of connections. The weird thing is my high e string up high on the fretboard sounds really weird... like ring modulated... but its very slight, however if you're listening closely and slamming on a bend up there it's very harsh and piercing. I havent tried every combination of tubes, it's difficult with the pro taking 6 preamp tubes. Does anyone have any suggestions... Could a tube tester help me locate which tubes I should throw out? I've figured this out myself... as some of them just stopped working (the collection used to be 15) The tap test is kinda difficult for me to judge, I mean its obvious when one is REALLY microphonic- but this isnt like terribly obvious, just mild and annoying I've seen shock mount tube sockets before. Does anyone know of anything like this? Should I try a 12ay7 or 12au7 in my reverb driver slot? for some reason I think this may be the problem and I dont have any very good 12at7's right now. I've also been running a 12ax7 or 5751 in the phase inverter. Sorry for posting such a simple tech problem, it's just that this is driving me insane. It has been a major problem continuously for years for me... sometimes hardly noticeable, and unhearable in a band, sometimes infuriatingly impossible to cure. I have recently(almost) completely overhauled my amp with everything from fitler caps, cathode caps and resistors, plate and slope resistors, phase inverter section, reverb components, tons of stuff! and it has never had a better cranked sound. It's so close to having that perfect blackface on 6 sound! Any advice would be wonderful!