#1
Hello,

I have a Peavey Classic VT 212 combo. It's either a late 70s or early 80s model. When I plug in my guitar and turn up the gain to around 12 o'clock, it starts a very high pitched squeal. I can hit a chord but get no sound, and the squeal remains the same pitch.

What would cause this? I have little knowledge about amps, so I'm hoping it's something simple enough that I can either fix myself by following instructions or something that can be done cheap in a repair shop.

Thanks in advance!
#2
if its a tube amp,

look up "eraser test" or "pencil test" and do it on your preamp tubes (the small ones) if it makes noise when you tap it the tube has gone microphonic. then buy new tube pull out the old one (after removing the metal shrouding if it has it still) and pull them straight up. take new tube push it in and you are likely good to go.
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.


"How to Hot-Rod the Hell of your Stratocaster for $50!" (Tuesday 2017-02-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/

Trashed ENG Shop Tour!
---> https://youtu.be/KQVlpYaulhA
#4
Quote by trashedlostfdup
if its a tube amp,

look up "eraser test" or "pencil test" and do it on your preamp tubes (the small ones) if it makes noise when you tap it the tube has gone microphonic. then buy new tube pull out the old one (after removing the metal shrouding if it has it still) and pull them straight up. take new tube push it in and you are likely good to go.


+1

Likely a microphonic tube
#5
It's a bit worrying that no signal is getting through at all. The pencil test may not show it up.
The better way to do it would be to take your spare 12AX7 and systematically try it in every position until the fault goes away.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band