last thursday, BRB had a practice. my vox ac30 started to make a whistling noise we had never heard before. we guessed one of the tubes went micorphonic. that is, when a tube gets jolted or old, the filiments become loose and vibrate like a microphone. barry guessed i needed a new set of power tubes.
so i took a little jaunt yesterday to broadway music in merrillville. the first guy i talked too had died black, gelled hair, black t shirt with some inane slogan, and carpenter jeans. i asked him what tubes i needed for an ac30. he looked at me like i was from a foreign country. just as he was googling the answer, the owner of the joint came out, paul. he was very very very helpful. he had me lug the amp into the store and we took the plate off the back. he was tapping on all sorts of things with pencils and turning the volumes up and down listening to the static and hum; commenting to me what each thing meant. i ended up needing three pre-amp tubes and one power tube. but i ended up buying the whole set of power tubes. he gave me three different pre amp tubes and told me what slots to put them for the best tone. he asked what kind of music i played, and i have a hunch he asked so he could tell me what order to put them him. i learned different tubes have different "voices." he also told me to wait four hours before changing the tubes so that the capicitors drained. if touched them after running the amp, he said "you'll never forget that for the rest of your life..500 volts." he had nice things to say about my amp. so i left feeling confident
later in the evening, i had abi and sam help me unscrew the plates and head. i extracted it, put it on the dinning room table and withing two minutes it was done. i tested it and no whistle. i threw up my hands like dr. frankenstein and shouted "it's...ALIVE!!!"