Tremoverb Clean Channel Problems -- Preamp tube?

[geekrobot]

Hello Fellow Mesa Lovers.

Really n00b question here, I tried searching a bit but couldn't find it among the sea of posts here... Apologies if this is an overly easy one that I missed.

So, my Tremoverb has an issue with it where sometimes when I turn it on, the clean channel is really quiet. It does not turn up very loud if i try dialing up the gain or volume--you can hear it get slightly louder, but it's still quieter than it normally would be on 1 if it were operating properly.

The high gain channel is fine.

Sometimes, if I put the amp on standby for a few or turn the amp off for a minute and then back on, the clean channel comes back fine. Also, i doublechecked that the tubes were seated okay and sometimes, it comes back after this, but i don't think they were necessarily unseated.

I replaced the V1 tube with a new 12ax7 (groove tubes). I know in the manual it outlines that problems with specific channels are usually preamp tube related, and then has a diagram of the tubes and what they're for, but to me it's a bit unclear.

So, my question would be--which tube should i replace? Which pre tubes have the most bearing on the clean channel?

It's not the recto tube, i tried the switch to solid state, and same deal. I also just replaced V1, as i mentioned, and both the power tubes (i have 2 in there to run it at 50 watts rather than 100).

It's a weird issue--like as i hold the guitar right now, the clean is fine, as is the dirty.

But sometimes when i turn it on, the clean is not properly working.

What's your verdict? Any help for this Recto novice would be appreciated.

 

[jbird]

Take that "known" good pre-amp tube and swap it with the others to see if and when it solves the problem! Also, I'm not one to condone pulling tubes to get your wattage down, I might set the amp back to "normal" operating parameters to diagnose the problem! BTW, have you compensated for the different loads on your OT? Correct speaker outs (ohmage)?

 

[jgventura]

Ya i'd agree... also, maybe V6 has to do with clean,... i'd think? I'm not sure... my trem-o-verb has the opposite problem on both channels for the reverb circuit... which I have yet to fix... and it's not my preamp tube... but I should probably check my reverb tank incase the springs came apart and need to be soldered back. if that is fine... im gunna have to bring it to the tech. hmph.

 

[geekrobot]

Thanks for the tips, guys!

Actually, i've looked around a lot on the half wattage thing for the dual recto's and it's apparently documented in the manual, i think it's safe. I will call Mesa to confirm, and maybe try to find out from them again wot they recommend regarding the clean channel.

As far as OHMage is concerned, i've since sold my attenuator, so it's the straight combo now. I guess swapping out the tubes with the new one--one by one-- would be the only real way to diagnose the problem. I was wondering about which tube has the most bearing on the clean channel because, as i mentioned, after some time or some tube-wiggling, the clean comes back, and it sounds great.

Hmmm....

 

[geekrobot]

Bumping this--haven't gotten the cash to just all out retube the preamp section, and the power tubes are brand new. Still have this problem--any suggestions? I hope it's a simple tube issue and not something to have to pay a tech to fix / lug around this beast :roll:

BTW, once i get the clean back up, i'm dropping some JJ EL34s in there. Mmmmm.