Lonestar Special - Tube issue or not?

[PHI_JAMMA]

Hi There:

I have a 7 month old Lonestar Special. Lately, I've been experiencing some issues perhaps you the forum users may be of some help.

After playing for twenty minutes (you can almost set you watch by it) the amp begins to cut out. The volume will go away and there will be some nose or static.

It does not matter what channel I am in. It does not matter whether I am using 5-15-30 in either channel.

I replaced ALL the power tubes with new Mesa Tubes. That did not solve it. I now have swapped one pre-amp tube that I had kicking around and I have tried it in all positions and it is still doing it.

I have tried turning off the reverb. I have tried switching to bright or warm on reverb. It still it does it.

Any thoughts?

There is the possibility my "test" pre-amp tube is bad or that perhaps I have two bad pre-amp tubes.

Joey

 

[timmerel]

This is a new one - best call Mesa directly for advice

 

[RR]

This is a new one - best call Mesa directly for advice

Yeah, bring it in.
I was going to say maybe the EL84s are a bit loose in their sockets because what you mentioned are sympton that I experienced but you said you swapped out all the tubes meaning there should have been better socket contact with the new tubes. But you said to no avail. I'm stumped.

 

[PHI_JAMMA]

Hi:

After trying all the new power tubes and no success. Then I tried swapping out pre-amp tubes...I still had the problem. I broke down and bought all new pre-amp tubes and had some success...ONLY because the rectifier tube went in the interim!!!

I received the new rectifier tube today and things are working great.

I think in the end not to discount multiple tube failures (either in pre amp, power or rectifier positons nor to discount the quality of the tubes you are using to troubleshoot.

Instead of doing one at a time I suggest all new in either power or pre-amp when troubleshooting as multiple tube failures in either area while changing only one tube at a time could take forever and leave you frustrated.

...and now that it is working you can always then try and find the "bad" tube in the lot.

So it's working great now.

 

[ylo]

HI PHI_JAMMA

Your phase inverter tube may have gone south. This tube drives the EL84 tubes. Both CH 1 and CH 2 signals have to go through the phase inverter. Check the manual to figure out which tube it is.
Chris

 

[PHI_JAMMA]

I think in the end it was multiple tube failures. The rectifier tube died during the process but I think I had at least two bad pre amp tubes as I have tried all the original power tubes back in the amp and it works fine.