Mesa Boogie tube issue

[sickest beast]

Hey guys,

Just today I was playing my Buster 200 and noticed a noise coming from the back of my amp. I went around back and put my ear next to the power tubes as I played. I could hear a loose, weird rattling/humming sound coming from one side of the amp, but only when I really exerted on the string, nothing when playing gently, or wasn't playing at all. So I turned the amp off and unplugged it, then gently tapped each power tube. As I suspected, the very first power tube from the left made the same sound when tapped as it did when I was playing through it.

I imagine I have a bad tube, how do I go about replacing it in a Mesa Boogie? I've never changed the tubes in this amp since I got it. I can see it does not have Mesa factory tubes in it.

Some might have a different stance on this than others, Mesa obviously wants me to use their tubes. Would I need to buy six new power tubes? Or can I get away with just replacing the first pair?

Thanks

[sickest beast]

Kind of a tube noob question, I know.

[B-string]

You are going to some different answers here.
It sounds like you bought the amp used? The bias circuit may have been modified to be user (or best ,tech) adjustable. Mesa provides no adjustment so they spec their tubes to run in the bias range without swapping resistors. You have a microphonic tube?( With the amp running you can tap gently and hear noise from the speakers)? Tube Depot and The Tube Store can spec tubes for Mesa, just specify your amp in the comments/special instructions on the checkout page.
Here is where the debate comes in: As an amp tech for over 40 years I would replace only the far left and far right matched pair at most (you still have a functional tube not a failed one). That is if no mods have been done. If you opt to replace all six you can keep the 5 good tubes as spares if anything happens in the future. Some will say to replace the three left tubes (I personally feel this leaves you open to a major imbalance JMHO. If you already had a good used tube that matches the bias requirement I would only replace the one until it was time to replace the whole set.
Others will agree or disagree.

Edit: If the amp has been modified it gets a lot more tricky to match the bias requirement that the tubes installed need unless they have a marking on them. Then you need the same brand with the same bias rating and a tech should still check that it will match well.

[sickest beast]

Originally Posted by B-string

You are going to some different answers here.
It sounds like you bought the amp used? The bias circuit may have been modified to be user (or best ,tech) adjustable. Mesa provides no adjustment so they spec their tubes to run in the bias range without swapping resistors. You have a microphonic tube?( With the amp running you can tap gently and hear noise from the speakers)? Tube Depot and The Tube Store can spec tubes for Mesa, just specify your amp in the comments/special instructions on the checkout page.
Here is where the debate comes in: As an amp tech for over 40 years I would replace only the far left and far right matched pair at most (you still have a functional tube not a failed one). That is if no mods have been done. If you opt to replace all six you can keep the 5 good tubes as spares if anything happens in the future. Some will say to replace the three left tubes (I personally feel this leaves you open to a major imbalance JMHO. If you already had a good used tube that matches the bias requirement I would only replace the one until it was time to replace the whole set.
Others will agree or disagree.

Edit: If the amp has been modified it gets a lot more tricky to match the bias requirement that the tubes installed need unless they have a marking on them. Then you need the same brand with the same bias rating and a tech should still check that it will match well.

Yeah I bought it used. And yeah, it sounds like I have a microphonic tube, wish I had known that word before I made this thread.

It's been to my tech (swapping the power and standby switches over a year ago) and he didn't say anything about any mods. As far as I know it's not modified, it just has non Mesa Boogie branded tubes in it, which I've read is fine. Mesa just matches their sets as close as possible I believe.

I'm not sure whether I should contact Mesa and get some of their tubes or just easily go out and buy a pair of JJ power tubes to match whats in there now.

[sickest beast]

I've read reviews of Mesa Boogie users who swear that their amp sounds a LOT better with the Mesa tested tubes vs. other brand tubes.

[rodl2005]

Don't worry about contacting Mesa, & if U R buying JJ tubes make sure u buy from www.eurotubes.com they're the JJ Dealers & will also match you a set to your amp, as mentioned above.
Edit: My Walkabout sounded better with different tubes than Mesa in it. & I've read about lots of ppl who've said they thought their amp sounded better with other tubes than stock Mesa's, which are simply rebranded Ruby or Sovtek, or similar. Each to his own

[B-string]

Originally Posted by sickest beast

I've read reviews of Mesa Boogie users who swear that their amp sounds a LOT better with the Mesa tested tubes vs. other brand tubes.

That is usually due to the "tight" testing Mesa does. The prices are not unreasonable either.
Depends on your budget and use, if you can afford it and you are gigging regularly replace the set. If you are not gigging much go with the JJs.

[sickest beast]

Cool, thanks guys.

[RickenBoogie]

If it were my amp, (and I owned a Buster for several years, awesome amp), I'd take it in to my tech and have him check it all out. Sure, it's cheaper to just swap tubes yourself, but the tech can have a good look at everything, and be sure it's all running at optimum performance levels.

[rodl2005]

Originally Posted by RickenBoogie

If it were my amp, (and I owned a Buster for several years, awesome amp), I'd take it in to my tech and have him check it all out. Sure, it's cheaper to just swap tubes yourself, but the tech can have a good look at everything, and be sure it's all running at optimum performance levels.

Sorry, I meant do this & then IF tubes are needed, I'd get a matched set sent from eurotubes/tubestore etc..
Yes, definitely get a reliable tech to install & bias & set all up right.

[georgestrings]

Originally Posted by B-string

That is usually due to the "tight" testing Mesa does. The prices are not unreasonable either.
Depends on your budget and use, if you can afford it and you are gigging regularly replace the set. If you are not gigging much go with the JJs.

I tried different tubes - including JJs - in both my Big Block 750 and M-pulse 600, and the Mesa tubes did sound better to my ears... I know they're just rebranded tubes, but think that the tighter tolerances they're having them tested to seems to make a difference...

I would also highly recommend going to Sweetwater for Mesa tubes - best price around(better than directly from Mesa, for some odd reason), and excellent service...


- georgestrings

[Caca de Kick]

George, you're talking preamp tubes, they're talking power tubes. Big difference. But that aside, I hated the mesa preamp tubes in my Titan, couldn't wait to swap them to JJ's fast enough.

Here is where the debate comes in: As an amp tech for over 40 years I would replace only the far left and far right matched pair at most

Yup that was the same thing Mesa told be to do way back when I bought my first Mesa 400. That if I had a failure and only had a pair of new tubes onhand to swap: the outer 1 and 6 pairs, or swap the inner 2 and 5 pairs, or the middle 3 and 4.

OP, you don't need Mesa's branded tubes. Honestly I think they are crappy tubes. The big tube dealers know what to put together for you if you tell them what amp you have. There's no science when you get them, just swap and go. But I like cleaning sockets and checking the socket pin tensions whenever I have the tubes out.

[sickest beast]

Originally Posted by Caca de Kick

OP, you don't need Mesa's branded tubes. Honestly I think they are crappy tubes. The big tube dealers know what to put together for you if you tell them what amp you have. There's no science when you get them, just swap and go. But I like cleaning sockets and checking the socket pin tensions whenever I have the tubes out.

For my situation right now (i'm paying for an expensive tube amp), I'll just go out and grab a pair of JJs and swap the 1st and 6th as a pair. I'll play it until I get my Marshall Super Bass, then if I want, later on I'll replace the whole set.

[Calaverasgrande]

Originally Posted by B-string

You are going to some different answers here.
It sounds like you bought the amp used? The bias circuit may have been modified to be user (or best ,tech) adjustable. Mesa provides no adjustment so they spec their tubes to run in the bias range without swapping resistors. You have a microphonic tube?( With the amp running you can tap gently and hear noise from the speakers)? Tube Depot and The Tube Store can spec tubes for Mesa, just specify your amp in the comments/special instructions on the checkout page. .

last batch of tubes I got from tube depot was WAY out of spec.
Lord Valve and Triode Electronics both have done me well.

[sickest beast]

what happens when a tube becomes microphonic? it still works, but is it the vacuum of the tube that is compromised? or something inside the tube?

I can sit and stare at the guts of a tube forever. lol I'm totally fascinated by them.

[Calaverasgrande]

Originally Posted by sickest beast

what happens when a tube becomes microphonic? it still works, but is it the vacuum of the tube that is compromised? or something inside the tube?

I can sit and stare at the guts of a tube forever. lol I'm totally fascinated by them.

If the vacuum is comprimised it gets ugly fast.
All tubes are a little microphonic. It is a matter of mechanical vibration, not air vibration.

[paganjack]

I have a buster and I've gotten tubes from dougstubes. Just another option to consider. I have been told that current mesas are rebranded Ruby's. I have been pleased with the results in mine. I love that amp!

[coreyfyfe]

Originally Posted by paganjack

I have been told that current mesas are rebranded Ruby's.

Sort of. Ruby tubes is a rebrander themselves. They just buy tubes made in china or Russia and slap their label on them. Same with Mesa. The difference between them and just buying some sovtek or shuguang manufactured tubes directly is that Mesa and ruby (and groove tubes for that matter) supposedly test and match for you. But if you buy from a good seller they'll usually do this for you, or at least for a nominal cost.

[B-string]

Originally Posted by Calaverasgrande

If the vacuum is comprimised it gets ugly fast.
All tubes are a little microphonic. It is a matter of mechanical vibration, not air vibration.

Leave out the little and you will be 100% correct The challenge is to make the structures ridged enough to move the point where vibration pickup is no longer in the range of human hearing. The rub is the grid wires are very fine and the spacing between them very small. Too tight and the wire stretches when heated moving the point back into audible range.

[Calaverasgrande]

I meant that when I first got into tube I was told by an older friend that you just warm up your amp, turn it on (with no instrument plugged in) and turn up the volume a little. Then tap each tube with the eraser end of a #2 pencil and the one that is microphonic will rattle. Well ALL tubes will rattle a little bit when you tap them with a pencil. The microphonic ones just do it worse. Or more objectively, they will rattle in sympathy with whatever your cabinet is doing and make you sound muddy. I often relegate microphonic tubes to my mi preamps and such. Especially if they are RCA's or Tele's or something!