This is exactly the kind of advice I need. I think I put in a matched set of power tubes not that long ago and I was hoping that wouldn’t be the issue.Squealing and popping is usually a microphonic preamp tube. Not always, but often.
If you tap on the tubes with a chopstick or pencil, with everything unplugged from the amp, and you hear tapping loud and clear from the speaker when you tap one of the tubes, it's that tube. All you have to do is replace it.
Note, however, that sometimes you hear some tapping when you tap on the v1 preamp tube (the one closest to the input). That's normal, unless it's quite loud.
This is exactly the kind of advice I need. I think I put in a matched set of power tubes not that long ago and I was hoping that wouldn’t be the issue.
This is exactly the kind of advice I need. I think I put in a matched set of power tubes not that long ago and I was hoping that wouldn’t be the issue.
It might be in the power section, you never know, but it’s the squealing in particular the hints at a preamp tube. It’ll make that noise, often, with a guitar even plugged in. I’m curious to see!I just had a similar issue from a set of power tubes I picked up. Rattle and popping, no squealing. Swapped back to old tubes and problem went away. Haven't diagnosed any further yet.
It might be in the power section, you never know, but it’s the squealing in particular the hints at a preamp tube. It’ll make that noise, often, with a guitar even plugged in. I’m curious to see!
I can vouch for getting whacked with a wooden spoon. They were my mothers weapon of choice.Les is correct about checking for microphonic preamp tubes with a wood pencil, chopstick, or wooden spoon, etc. However I've also recently had some power tubes going bad, which resulted in some crazy squealing & intermittent cutting-out. I peeked around back to see one of the two power tubes glowing purple-red in a way that didn't look good. Turned it off right away, then changed the power tubes... all better now.
You, too, must have gone microphonic!!!I can vouch for getting whacked with a wooden spoon. They were my mothers weapon of choice.
I’m a survivor.
HAHAHA!You, too, must have gone microphonic!!!
Well I was wrong. I replaced all the pre amp, effects loop and reverb tubes. It was still popping. Then I looked into the power section (the front panel was off) and I could see one of the el84s glow super brigh and the it would pop as it discharged.
that was one of a matched set of JJ el84s I installed not too long ago. I put the Mullards that came in the amp back, which cured the pop, but now it’s noisy (probably why I retubed it.