Mesa Boogie problems?

[Deneb]

Hey, this isn't about mine but rather about my friend Pete's Mesa Triple Recto.

he has an older 2 channel model.

The problem just happened yesterday when he got his soloist in the mail (He won a soloist that Pat from Damage Plan owned).

The problem is the Red channel has lost all of its gain. It basically sounds like it's on vintage mode with the gain at like 1 or 2, almost clean sounding, and this is while it's in modern mode.

His orange channel still works great, but it's the red channel. I told him to swap all of the preamp tubes like this. Take the FX loop tube (since he's not using the loop) and swap it with position one. Then swap it with position two, et cetera.

He did that with no change. The tubes are probably 5-6 years old, but are showing no signs of noise or anything like that.

What could the problem be?

[Misanthrope189]

Well, I thought that Triple Rectos were 3 channel regardless of year.

Preamp tubes, although they may not show signs of noise or blow out with big flashes of blue light like a power amp tubes doesn't mean that they aren't bad. Also, if you have stock Mesa preamp tubes, check the fx loop tube, because Mesa usually puts in a tube like a 12au7 instead of the 12ax7, because it has slightly less gain, so it's less likely to make noise in the fx loop. Putting the fx loop tube might not help your case.

Also, loss of gain, muddiness, all of that is a sign of preamp tubes gone bad. Usually you'll lose volume with the power tubes, and gain, clarity, and liveliness in the tone with preamp tubes. 5-6 years? How often does he play on the unit? If it isn't the tubes, it could be a switching problem with the circuitry; I had an amp that acted like it was gender-confused, I'd switch to the gain channel from the clean, and it would mix the two, not completely activating the gain circuit, so it was like a dirty clean. Terrible, terrible situation.

Anyway, best of luck to you.

Cheers,
Nick

[Deneb]

He plays it just about everyday. Nah, the older ones are two channels.

I've got original tubes in mine, but I keep spares everywhere I go for every tube in the amp. They have like "guidelines' on when to change, but if they are working and have readings in okay levels, it's fine to keep using them.

I checked my FX loop and it's got a 12AX7 in it, and in all of the other positions. I'll email him what you said though and have him check that out. If it was my guess, like you say I think it's the preamp tubes.

[SpiralArchitect]

could be a cold solder joint, I just had my engl powerball serviced, I DON'T gig with this amp, but there were 43 cold solder joints found on the board, and it's one of those trace side up deals so it's hard to fix, any how the amp works great now, as we also had to replace two preamp tubes.

it's maybe a thermal issue? but if you've swapped tubes to no avail you might have to take it to a tech, at least I would, could be a number of things, it shouldn't need a cap job, but if manufacturers are using cheap components then it might be a possability, my tech said that on my ENGL there were ruby caps which are cheapo garbage and he said to replace them with mallory of the same # so I will in the future.

anyhow, just some thoughts!

Chris

[jgcable]

Swap out the tubes first and rule them out.

[Riscchip]

Give Boogie a call and talk to Michael Wolf. The man is really smart about diagnosing potential issues with the amps. He's had me up and running in 5 minutes over the phone more than once.

[Deneb]

Turns out it wasn;t the tubes. It's a problem they've had before, has something to do with the channel switching.

12$ in parts plus bench time.

[Misanthrope189]

yes! More faulty Mesa action, haha.

Glad everything's up and running.

Cheers,
Nick

[Gio]

dude, he wont that guitar on ebay right?

my buddy sold it on ebay


small world

[Deneb]

yeah he won it. He's having some issue with it, he says when he pulls the bar up, the back of the trem hits the back plate. I said he's stupid and doesn't know how to work a floyd.

How did he aquire it from Pat?

Misanthrope, he's had it for like 6 years, and it was 2 years old when he got it. I thought it was newer...get this shit...original tubes! I couldn't believe that. The guy at Mesa said, if the orange channel works fine, it's not tubes. He played it from 3-6 hours every day since he's gotten it, so to spend a little upkeep on it, I don't think it's a big deal.

Gio, I guess it is a small world man