Help identify this tube problem.

Artie

Artie

Peaveyologist
Update at post #17.

Hey all. My experience in tube amp troubleshooting is sparse. I just fired up my Traynor YCV20WR and it has a strange sound. Imagine dropping a quarter in a Mason jar, and setting it on a speaker that's playing loud. Is this something a tube would do when it's going bad?

Thanks;
Artie

The tubes seem to be seated well and are held in with hefty tube retainers.
 
Last edited:
Hi Artie. Is it a preamp or power tube? Have you tried tapping each tube while the tubes are warmed up with a pencil or chop stick? That might give some kind of clue which tube is going bad or microphonic.
 
Yes, turn it on and make sure the speakers get volume.
tap lightly with something wooden on each tube.

Sounds like one of them has gone microphonic, or is ready to die, to me.
probably a pre amp tube, probably #1 or #2
But that's just my guess.
 
Thanks guys. I'll do the tap test 1st thing tomorrow. There appear to be only 3 tubes. I'm thinking one preamp, and two output, in a push-pull mode. I'll report back tomorrow.
 
I couldn't wait. I see what's going on now. The three tubes I can see are the splitter and 6BQ5 push-pull tubes. The two 12AX7 preamp tubes are mounted horizontally inside the chassis. I'll have to take this thing apart to get to them. Tapping on the splitter and outputs did nothing. So it's either the preamp tubes or the voice coil.

Film@11.
 
Have a look at the tubes when it does that and I’m pretty sure it will reveal itself. If not, grab a pencil and give each one a little tap.
 
Beer$ said:
Have a look at the tubes when it does that and I’m pretty sure it will reveal itself. If not, grab a pencil and give each one a little tap.
Click to expand...

Yeah, I did with a wooden spoon. No affect. The preamp tubes are hidden behind a metal plate that needs a Craftsman torque wrench to loosen. I'll work on it tomorrow.

Traynor_Plate-01_resize.jpg
 
ArtieToo said:
Yeah, I did with a wooden spoon. No affect. The preamp tubes are hidden behind a metal plate that needs a Craftsman torque wrench to loosen. I'll work on it tomorrow.

Click to expand...
A wrench? Boy they’re really in there good. All of mine just have thin, bayonet mounted covers that I keep losing. Any time I had a lawnmower sputtering sound, I could see the culprit tube flashing away.
 
To me it sounds like it's probably a preamp tube going microphonic. Hope you got that bullet-proof cover off and did the wood stick tap test. If you can't see one tube glowing redder than the other, the tap test should reveal the microphonic culprit.

Did you get this straightened out?
 
GuitarDoc said:
To me it sounds like it's probably a preamp tube going microphonic. Hope you got that bullet-proof cover off and did the wood stick tap test. If you can't see one tube glowing redder than the other, the tap test should reveal the microphonic culprit.

Did you get this straightened out?
Click to expand...

Not yet. It got put on a back burner while I deal with some other "life" issues. They come more often as we get older. :cool:
 
So, turned out to be the EL84/6BQ5 outputs. Fortunately, I had a Tube Depot TubeCube 7 amp that uses the same outputs. Swapped those in and the rattling seems to be gone. Put the originals back in and the rattling was back. The Traynor used Russian Sovteks, while the TubeCube used some Chinese things. Since the Traynor is a pretty sweet little amp, I think I'm going to opt for some decent replacements. (Assuming I can get them.)
 
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