#1
I've already posted this on the "boogie board" and I didnt get much help.

Here it is.

I own a new (less than 10 hours) Mesa boogie Road King II. The other day I was messing with channel two, I turned it to "brit" mode, and the tone of the amp completely changed, very very thin and sizzly, And wasn't just brit mode anymore it was every channel. Well after some trouble shooting and blowing 3 12ax7 in the V2 position. I found out with a fresh tube everything was fine until I engaged the brit mode on channel two, The brit mode was causing the tube to blow and was the reason for the change in tone...... Has anyone else experinced this or something similar?
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#3
Quote by 311ZOSOVHJH
Is this new new?

What kind of preamp tube did you put into V2? What brand?



Yes as stated above the amp has less than 10 hours total on it....The first one was a mesa branded and the second one was a marshall branded and the third one was a ruby.
"People worry too much about tone instead of just rocking out"
#4
I hope you have some kind of warranty on that amp...
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#5
Call up Mesa. That'll help you way more than this thread will. That's a really weird problem.
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#6
yeah, i'd say that is a little too specific of a problem for anyone here to help with, sorry dude
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#7
Quote by JaredFace
Yes as stated above the amp has less than 10 hours total on it....The first one was a mesa branded and the second one was a marshall branded and the third one was a ruby.

I understand.

I was more interested to see if it was still second hand or what your warranty situation was. I'm not an amp tech btw.

I believe some amps have a cathrode follower in V2 meaning you have to be more carefull with what you put in there. No clue on Mesa's. Someone here knows the answer so I'll keep bumping.

Do you have the Marshall and Ruby tube there with you? Mesa amps are very well built so this is an anomoly I'm sure.
#8
Call Mesa. That's a very odd sounding problem. Mesa's customer service is supposed to be extremely good.
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#9
My first guess is that the brit mode changes the cathode bypass pair on V2, which makes sense from a voicing perspective. What may have happened is that one of the two components that the switch introduces has gone bad, which would blow V2. Since V2 is a shared tube (IIRC, I don't have a schematic for this particular amp), blowing that tube would cause problems with the other channels too.

The good news is that if I'm right it should be a very cheap and easy thing for a tech to fix. The bad news is I'm not always right.

Good luck, let us know what it turns out to be or if you need more help.
#10



Colin, not to put you on the spot but would you recommend the fix locally or shipping off to where ever Mesa says for repair? Would anyone happen to know how Mesa feels about putting different preamp tubes in their amps while under warranty? Policy wise?

Just askin.
#11
Return the amp.

Fixing a brand new amp isn't worth it when those amps have a 5 year warranty...
Quote by Dave_Mc
I've had tube amps for a while now, but never actually had any go down on me
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#12
Quote by 311ZOSOVHJH



Colin, not to put you on the spot but would you recommend the fix locally or shipping off to where ever Mesa says for repair? Would anyone happen to know how Mesa feels about putting different preamp tubes in their amps while under warranty? Policy wise?

Just askin.

If it's still under warranty, there's really no reason to repair anything in a tube amp except for replacing tubes. A non-warranty repair will void your warranty and drop resale value, which negates the entire purpose of buying new amp in the first place.
Tube changes don't void the warranty of any amp company I'm aware of, though technically opening your amp to bias might in some cases. With preamp tubes though, I'm sure they'd understand.
#13
Quote by Roc8995
Tube changes don't void the warranty of any amp company I'm aware of.

Bugera.


Quote by Dave_Mc
I've had tube amps for a while now, but never actually had any go down on me
Quote by jj1565
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#14
Quote by 311ZOSOVHJH



Colin, not to put you on the spot but would you recommend the fix locally or shipping off to where ever Mesa says for repair? Would anyone happen to know how Mesa feels about putting different preamp tubes in their amps while under warranty? Policy wise?

Just askin.


They strongly recommend you do not do so.

Mesa recommends using Mesa only tubes, but the warranty does not say that doing so will void the warranty.
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#15
Quote by ragingkitty
They strongly recommend you do not do so.

Mesa recommends using Mesa only tubes, but the warranty does not say that doing so will void the warranty.


Right, which is kinda where I was going with that. He put a 'marshall' tube in there whatever a marshall tube is, so don't tell Mesa that or they may consider the warranty void.....which to be honest was the feeling I got all along with the OP.

Roc8995 - thanks for jumping in.
#16
Quote by 311ZOSOVHJH
Right, which is kinda where I was going with that. He put a 'marshall' tube in there whatever a marshall tube is, so don't tell Mesa that or they may consider the warranty void.....which to be honest was the feeling I got all along with the OP.

Roc8995 - thanks for jumping in.


Based on what I understand about their tube replacement recommendations from my Mark V. They're not gonna void your warranty just because you didn't slot a Mesa tube back in. Though they do not recommend it due to tonal performance.

I'm inclined to agree that it may be due to a cathode follower stage... altho I have no damned idea how to identify whether an amp has a cathode follower stage or not. Although I am inclined to believe that Mesa tend to have cathode follower stages due to their amp design, more so since the Road King is designed to be a high gain amp. Don't quote me on this though, its a stab in the dark for me.

Also correct me if I'm wrong, shouldn't a cathode follower stage be after the phase inverter? If that is the case, it shouldn't blow out your V2. Even if it does... shouldn't it kill the valve rather than kill the amp's circuit?
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#17
^No clue really. Maybe Roc will jump back in here.

I know on some (most?) Marshall amps V2 is a cathode follower so that whole bit about 'Brit Mode' on the Mesa made sense to me. The PI Phase Inverter is usually the last preamp tube in most amps no - as its responsibility is to feed the power tubes with a signal?
#18
Quote by 311ZOSOVHJH
^No clue really. Maybe Roc will jump back in here.

I know on some (most?) Marshall amps V2 is a cathode follower so that whole bit about 'Brit Mode' on the Mesa made sense to me. The PI Phase Inverter is usually the last preamp tube in most amps no - as its responsibility is to feed the power tubes with a signal?


I give up then... its getting far too technical for me.

Call Mesa... they'll sort you out.
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#19
New amp with non-tube issues? Warranty time! Not worth the hassle to fix imo. I agree with Colin it could probably be an easy fix, but why bother if you can get a brand spanking new one fully functioning?
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#20
Quote by Mark G
New amp with non-tube issues? Warranty time! Not worth the hassle to fix imo. I agree with Colin it could probably be an easy fix, but why bother if you can get a brand spanking new one fully functioning?


I think Mesa actually does repairs instead of replacements.

But yesh... just let Mesa handle the difficult work.

Don't void your warranty for nothing... a Road King II ain't exactly worth a bucket of quarters.
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#21
Quote by ragingkitty
I think Mesa actually does repairs instead of replacements.

But yesh... just let Mesa handle the difficult work.

Don't void your warranty for nothing... a Road King II ain't exactly worth a bucket of quarters.


Even if they just do repairs, it would still become as good as new with the warranty intact.
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#22
In my experience, you have to bring your Boogie to an authorized seller who will then evaluate it for you.
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#23
wow, thanks everyone.... I already know what to and what not to say to mesa when I call them, regardless the problem wasn't started because I changed to a different tube, it blew the original mesa branded first, I then replaced it with a marshall branded and then another mesa branded. But thanks for all your help. Laters
"People worry too much about tone instead of just rocking out"
#24
Sending it back to Mesa is the best idea. Not worth messing with an amp still under warrenty. Power tubes usualy come after phase inverters and cathode followers usualy are before the tone stack as a cathode follower is not dragged down by the tone stack.
#25
Quote by JaredFace
wow, thanks everyone.... I already know what to and what not to say to mesa when I call them, regardless the problem wasn't started because I changed to a different tube, it blew the original mesa branded first, I then replaced it with a marshall branded and then another mesa branded. But thanks for all your help. Laters


Lets not mention that to Mesa.

My experience with warranties is that many companies try to find a way to void your warranty for the smallest reasons.

While I don't believe Mesa practices that... best not to give them a reason to start.
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