Rectifier issue.

[JackBootedThug]

Was playing and all of a sudden it started making all kinds of screeching sounds… I know I suck but I have never had an amp start screaming for me to stop … does the same on both channels. I’m playing in stereo with my 6505 and it’s fine…. Any ideas?

 

[Dan Gleesak]

Most likely thing would be a microphonic tube. V1 especially, but could be any.
Do you have anything in the loop? Maybe it’s slamming the amp too hard
If it’s a mesa rectifier see if there is a difference between tube/solid state rectifier modes
Like always it’s best to take any effects out of the chain and plug straight in if not already

 

[JackBootedThug]

Going to check it right now. I’m running the ms3 in its loop for effects but I have my tuner, whammy drop,wah, Mxr overdrive, vibe and mxr noise clamp running in front of both…lol… probably something in there fucked up…

 

[glpg80]

Take all of the pedals out completely. Just use the amp. Swap a known good preamp tube in for V1.

Slamming the front of the amp is harder on V1 than most other preamp tubes so it will degrade faster. I agree with above that it’s likely a bad V1 preamp tube

 

[JackBootedThug]

Straight in it’s fine….. time to play effect bingo….

 

[Dan Gleesak]

Straight in it’s fine….. time to play effect bingo….

Could still be a microphonic v1. It may be fine with just guitar but a normally functioning pedal might be enough to make it start ringing.

I haven’t had a recto in a while, does the lower gain channel use a different tube for its first gain stage than the higher gain?

You might be able to run your pedals as is into the low gain channel and see if you still get the screech. If not, look for the tube the two channels don’t share