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Tube Amp question


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I'm having some trouble with my amp/preamp. Maybe some of you have experienced the same and help with a course of action...Here's the details.


I am encountering a dip in gain when playing on a dirty setting. I perceive this as a drop in distortion rather than volume, though I have experienced that as well. Recently, I retubed everything to remedy the problem, but it still exists.

I understand that one of the obvious things to do would be to take it to a shop to get it looked at. I've had prior non-positive experience doing that where the technician hands me my amp and says, "Couldn't find anything wrong". So, I figured I'd ask some folks who might know.

If it matters, here's what I've got:

Mesa Boogie Triaxis preamp. It uses 5 12AX7 tubes.

My power amp is a M/B 395 Simul Class. It has 4 6L6 power tubes per side as well as 4 12AX7 tubes in its preamp section.


Any ideas or suggestions?



Everybody knows rock attained perfection in 1974. It's a scientific fact. - Homer Simpson
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Are you saying that when you're playing with high gain... things are fine for a while and THEN there's a dip?


Does the "dip" continue on or is it transitory?


You mentioned you "retubed" it... and that didn't change anything. That may be as far as a non-amp repair guy can take it... unless there's something weird in say your power to the amp or something.


Does this ALWAYS happen? Does it only happen after you've been playing for a while or immediately as you move to more gain?


Maybe with more info, we can give you more ideas.



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Yeah, things are fine and then there's a dip. It happens intermittently. Pretty much always happens, sooner or later. Kinda frustrating, you know?!

I don't expect anyone to give me sure fire answers. Just thought someone may have had previous experience with the same amp or problem.


Soooo, anyone wanna buy an amp?

Everybody knows rock attained perfection in 1974. It's a scientific fact. - Homer Simpson
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First off, since it's only with higher gain settings, I'd guess that it's a problem with the preamp.


Secondly, since it's intermittant, I'm guessing that it's a bad connection of some kind. Unfortunately, the TriAxis is a very sophisticated unit with (I think) digitally controlled switching. That means lots of relays and ICs so the problem will not eb easy to diagnose.


Best thing would be to take it to an authorized Mesa/Boogie service center. Is it still under warrantee?

"You never can vouch for your own consciousness." - Norman Mailer
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