Sounds like you may have a bad tube in there somewhere. I work on amps, and I've found that this issue is usually related to a tube.

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When you hear the signal drop out, turn off and unplug your amp. Give it about 15 minutes and listen to the amp...if you hear any feedback or popping sounds you'll know its a bad tube.

Also, check the color of the tubes. Any purplish coloring means a bad tube.

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I wouldnt know for sure without looking at the amp, but given the loss of signal its generally related to a tube.

I’ve had a couple amps worked on at Big Crunch and have always been happy.

link

Came here to say this. Had my Fender Twin serviced by Big Crunch - they did a great job. Bill’s Music in Catonsville has also always done a great job working on my gear too.

Just want to throw in my big crunch recommendation. Also old town lutherie for any guitar issues.

Interesting. Against my better judgment I opened her up. The three preamp tubes all look the same. But one of the two power tubes (the EL84) looks different. One is silver/metalic on the top whereas the other is a dark, almost obsidian color. It's subtle, but they do look different.

Going to try and upload a pic.

https://www.reddit.com/user/The_Waxies_Dargle/comments/yosnzr/the_good_the_bad_the_tubes/?utm_medium=android_app&utm_source=share

Here to cast another vote for Big Crunch. About a dozen of my friends have had their amps serviced there, and they’ve all been happy with the results every time.

^ 2nd this. Especially if the Amp starts with full power and then dies off after a minute of use. Good sign that one of the tubes isn't able to handle the amperage running through it when there's more current draw. You should try buying a new tube and replacing one at a time and see if the issue still persists and work your way down the line with the one new tube until you've tried them all.

You could save yourself decent money by doing this by not having to pay for getting it serviced. Then if that turns out to not be the issue you still have a new tube which you will need eventually anyhow.

This is what I am doing. I am replacing the power tubes first and then I will try the others.

Any idea which part of the inside fo the amp I shouldn't touch if I don't want to die.

Big Crunch vote here as well!

Yeah good move, it might just be one tube so you might be able to get away with buying one and try replacing one at a time til you find which one is out. But you should be fine, just have the Amp unplugged when you remove and replace each tube and then plug it back in to try it out.

Bill's Music, they have fixed anything I've ever given them superbly, solid team of techs.

https://billsmusic.com in Catonsville, just a few blocks inside the Beltway exit. Onsite free parking next to the store or metered parking in front of the store.

Not quite in Baltimore, but Just Audio in white marsh specializes in tube and vintage audio.

Thanks for all the answers everyone. I'm going to take a run at it myself and then it's going to be either Big Crunch or Bills (who I love).

Peace!

Yeah, you should have no issues pulling out and replacing each tube to see if you have a faulty one in there somewhere...

As far as the parts you shouldn't touch, all that stuff is inside the head....it's those big capacitors you need to watch out for. Feel free to message me if you have any other issues. I also have a bias probe if you should need.

Thank you, man. I have it torn apart and have pulled the tubes just to look at them. I'll 100% hit you up if I need a bias probe.

Um...anyone know what a bias probe is used for?

Bill's Music

REPLACED THE TWO POWER TUBES AND IT'S RIGHT AS RAIN. THANKS FOR YOUR HELP!

GOT TWO NEW POWER TUBES AND IT WORKS GREAT. THANKS FOR THE INPUT!

Hey awesome! I'm super glad to hear it. You just saved yourself some good money and time without your Amp. And doing that stuff makes you feel super accomplished and badass hahah. I haven't taken my equipment to the shop in like 10 years thanks to YouTube and strangers on the internet, glad I could be on the otherwise and help!

Right on!