Power tube issue?

  • Thread starter Deleted member 3520
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Deleted member 3520

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Hi, turned on my Herbert today and it sounds like there is thunder happening in the cab, this deep rolling noise that I e never heard. My tone sounds fine, but this noise sucks. Doesn’t change with loop in or out, channels changing, volume/EQ change, just a constant rumbling kind of noise. Kind of seems to rise and falls, but the actually guitar volume does t change with it, maybe a bad Preamp, PI? I tried to capture a video, but not sure if you can hear it.

https://youtu.be/DhL0isO0R2E
 
Start off with the pencil test. Turn it on and tap the tubes, if you hear that you have a lot of noise, then you have a bad (microphonic) tube. My bet is that it is a preamp tube that is on its way out.

I must say that I do not own a diezel, but I have had a lot of different amps.

Good luck!

Cheers.
 
That was my first diagnosis, didn’t hear anything, maybe I’ll try again. I’m thinking if it’s Preamp it’s gotta be v1 or PI, cause it happens in every channel, loop on or off. Im gonna swap some Preamp tubes later and see.
 
My Einstein does this, but usually goes away. I know it doesn't help you, but I thought I could at least say you're not the only one haha! :)
 
fatbagg":3jrvr3gv said:
That was my first diagnosis, didn’t hear anything, maybe I’ll try again. I’m thinking if it’s Preamp it’s gotta be v1 or PI, cause it happens in every channel, loop on or off. Im gonna swap some Preamp tubes later and see.

Exactly. Try a new tube in V1 and PI that is what I would do.
 
V1 and V3 are used by all channels; PI is a definite consideration.

[Edit:] Cranked the video to hear it. Does it happen on mute - just as an off chance diagnosis. If volume doesn't effect it - it's not a preamp tube - how old are your powertubes? Are they all the same?? Matched 6 in your Herb?? I'd be interested to know what moving them around or - through process of elimination - take a pair out one set at a time and see if it keep happening. Might be heater issues. Or, worst case scenario - OT.....

Has this been remedied?
 
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