Amp issues, probably not tubes?

Tor

Tor

Riffologist Extraordinaire
I have a Valvetech Hayseed 30 (a Vox clone) I have been very happy with. However, a few weeks ago, the sound just disappeared in the 30W mode. Switched it to 15W and it worked fine. Good sound and all. I guessed it had to be 1 or 2 of the 4 power tubes that were failing. A couple of weeks later, the lighting in the lamp failed. Still good sound, though. A week after that again, in its 15W mode, the amp volume was drastically reduced, with a nasty and congested distorted sound when I played some chords ("farting out?"). So I turned off everything and haven't tried it since.

This is probably more than normal tube wear and tear, I guess? Do you have any idea what it can be attributed to?
 
Re: Amp issues, probably not tubes?

gibson175 said:
Have you swapped out the tubes first?
London to a brick on says that its the toobs.
Click to expand...

Will do! I have two spares, but I am gonna order two more. Can I swap all as I wish without any special regard, or do they need to be swapped pairwise, since I've ordered matched pairs before?

crusty philtrum said:
Is the lamp an incandescent globe or a LED ?
Click to expand...

99% sure it's the former you mention..!
 
Re: Amp issues, probably not tubes?

Dumb question, is your output impedance set correctly? I was just talking to a friend who's cab was wired completely wrong, so he's been running at a completely wrong impedance. He had just blown a power tube, had it retubed and happened to replace speakers too finding the issue.

If your issue is power tubes going, I'd make sure to confirm your impedances.
 
Re: Amp issues, probably not tubes?

There are "things" that can go bad wrong in those power reduction circuits, and then run the piss out of the power tubes.
I am not saying that IS what is going on here.....but you need to check THAT circuit and see where the bias is at in each case....also screen resistors, and all that.
Have you contacted Rob.?
Is your amp under warranty.?
If you are asking these questions on a Forum, I would definitely give him a call before you proceed.
It CAN be bad tubes. They, sometimes, fail in aggravatingly large numbers.....how long have you owned the amp.?
Gorgeous sounding amps btw.....
 
Re: Amp issues, probably not tubes?

PFDarkside said:
Dumb question, is your output impedance set correctly? I was just talking to a friend who's cab was wired completely wrong, so he's been running at a completely wrong impedance. He had just blown a power tube, had it retubed and happened to replace speakers too finding the issue.

If your issue is power tubes going, I'd make sure to confirm your impedances.
Click to expand...

Can one check these things easily without electrocution? I have a multimeter, and know a bit on how to work with guitar circuits, but getting into the amp is a whole other game..

zzmoore said:
There are "things" that can go bad wrong in those power reduction circuits, and then run the piss out of the power tubes.
I am not saying that IS what is going on here.....but you need to check THAT circuit and see where the bias is at in each case....also screen resistors, and all that.
Have you contacted Rob.?
Is your amp under warranty.?
If you are asking these questions on a Forum, I would definitely give him a call before you proceed.
It CAN be bad tubes. They, sometimes, fail in aggravatingly large numbers.....how long have you owned the amp.?
Gorgeous sounding amps btw.....
Click to expand...

- yup, he thought it could be the tubes, so he recommended swapping those first
- have owned it since early 2011, I swapped tubes for the first time last fall, actually. I live in Europe, so sending it in to him for repair is not really an option

Yeah, love its sound :)
 
Re: Amp issues, probably not tubes?

Sorry...did not look at your location.
You guys have some awesome amp builders in that part of The World.....I would ask around for a decent tech.
good luck
 
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