5150 issue

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misterspockyall

misterspockyall

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I got a peavey 5150 combo that is acting up on me. It's making a bad noise, I'll pause for feedback and hiss related jokes lol.

The past few months, more and more frequently I'll notice on the gain channel, the amount of gain will fluctuate in waves as I'm playing, and every so often, the amp will make a loud hum/horn type sound, like a low frequency feedback that is far louder than the notes I'm playing.

Tubes? Something more nefarious? Any ideas would be helpful before I resort to shipping it to a doctor.
 
Oscillation is typically a preamp tube. id start there.
 
I'd guess preamp tube. However, they are notorious for the effects loop jacks getting dirty too - Spray them inside with contact cleaner, and plug/unplug a cable in each one a few times, spray, rinse, repeat. It happened to me with a couple older Peaveys, and it acts just like a preamp tube going bad!

This happens, whether you use the loop or not. Crap builds up in there.
 
Yeah, before you send it to the amp doctor, get yourself at least 1 known good 12ax7 and swap out the pre-amp tubes, one at a time, and see if that fixes it.
Servicing the loop jacks is good advice as well.
 
Dirty loop jacks. Plug a jumper cable in the loop and see if it gets better. Then look at tubes.
 
Jerry, I tried that on a CAE 100+ and that extra 12ax7 kicked in more gain and sounded killer. I don't think all loops do that though. Maybe u can explain...
 
JerryP":1729hxyn said:
Dirty loop jacks. Plug a jumper cable in the loop and see if it gets better. Then look at tubes.

Thank you all for the input, I'm gonna get some cleaner and give the jacks a good working, then work through the preamp tubes one at a time. Jerry, you were on my short list of folks to contact if I can't sort it myself!
 
Cleaned the jacks, nothing. Started rolling a good 12ax7 through the preamp. When I put it in v4, the symptoms stopped. Fingers crossed that it keeps working fine.

I think I still want to have it looked over by a professional at some point. But thank you all for your help!
 
misterspockyall":2376ckul said:
Cleaned the jacks, nothing. Started rolling a good 12ax7 through the preamp. When I put it in v4, the symptoms stopped. Fingers crossed that it keeps working fine.

I think I still want to have it looked over by a professional at some point. But thank you all for your help!

Sounds like the likely culprit!
 
Welp, a year later, all new tubes and a trip to the local amp doctor, I got it back and I love it! They went through and resoldered a bunch of shtuff and gave it a clean bill of health. The crunch channel alone has more gain than most will ever need and the lead channel sounds like a double boosted Marshall. Y’all know what these are so I’ll stfu, but I’m so happy to have mine back. It has so much bounce and forgiveness while remaining aggressive as hell. Everyone should own one at some point just for the lolz
 
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