Mesa Single Rec Issue

[jak0lantern01]

I bought a single rec combo amp about a year and a half ago and seem to go through tubes a lot more frequently than I would expect. I just replaced tubes a month ago and it's already started to show symptoms of a problem (microphonics especially, but also some buzzing, etc.). The amp had to go into the shop last month due to what I'll refer to a catastrophic breakdown. The guys in the shop told me that a resistor melted out and had to be replaced, probably caused by a failed tube. Well, I have it back one month, and in that time I played one gig and have had practice sessions every weekend. I'm thinking the resistor and tube problems I've had are just a symptom of some other bigger problem. I use the standby switch when not in use. Anyone have any idea as to why I'm going through so many tubes? It's still under electronics warranty. Thanks.

[jak0lantern01]

No takers here on why tubes would be failing on an amp at an accelerated rate? C'mon, someone has to have some thoughts on the issue.

[Ray Ivers]

C'mon, someone has to have some thoughts on the issue.

Oh, absolutely! Could you elaborate on this statement:

I use the standby switch when not in use.

Ray

[TD_Madden]

Which tubes are in-question....from the microphonic standpoint I'd suspect preamp issues, butit would help to know the types of tubes...even manufacturer if possible.

[jak0lantern01]

What I meant was, that when taking a break, I use the switch, so it's not like I'm abusing the tubes or anything. Sorry about the rambling post, the problem is both strange and troubling.

[jak0lantern01]

Mesa tubes (12AX7's and El34's with the correct bias selected). I just replaced the pre-amps for this reason, I couldn't seem to narrow down the source. I've also had to replace power tubes after the amp repeatedly sounding 'dirty' and/or weak. Bandmates notice the problem also. Could this be a power related issue?

[jak0lantern01]

Are we already calling it quits on this one?

[Steve Conner]

If you play real loud with loads of bottom end, your tubes could be getting shaken to an early grave by vibrations from the speaker. Try using an extension cab instead of the internal speaker, and see if they last longer, if so, we found your problem

[jak0lantern01]

I only run the bass at about 50%. After that, we start to get mud. I was testing the amp the other night, just a guitar straight into the amp, no fx or anything, and cranked the master, played nice, or so it seems. Possibly a problem with the FX loop? I usually have FX hooked up.

[Mouthurst]

Try some good quality NOS tubes and see what happens, they should last longer. Or spend the extra coin and buy quality.
Ive got Mullards, Rogers, telefunkins and Sylvanias which have been tortured for years and still going strong and a box of newer used tubes which are NFG.
New tubes are meant to be replaced with built in life spans IMO.
Also if the power tubes are getting lots of vibes put some dampening rings on them it may cut down on the wear and tear.
That amp is probably trying to get as much out of them as it can using "mesa" watts.

Thats what I think
Good luck with it.

[jak0lantern01]

Mesa watts? Dare I even ask?

[Mouthurst]

Mesa watts? Dare I even ask?

Well It was kind of a rumoured joke I heard from a freind because by using advancements in amp design they were squeezing every ounce of power they could from a pair of EL84's. Some thought they were measuring different than the generally accepted methods. Maybe thats shy those amps should use those tubes, tubes gotta be tough to take the designs.

[stokes]

Although its true that Mesa's as well as other high gain amps are tough on tubes there is no reason you cant use other tubes besides Mesa's.They use Russian and Chinese tubes- the only thing "special" about their tubes is that they test and grade them to fit a certain bias range.I have all NOS tubes in my MKIIC+ which both my sons use regularly and the tubes have been in the amp for 2 years now and are still going strong.As Steve said vibrations as well as pushing the amp hard will shorten tube life,but a month is way too short.Since you say it is still under warranty I would suggest taking advantage of that warranty and have the amp checked out.

[jak0lantern01]

I just had major repairs done on the amp. The amp was sounding lousy, really bad, to the point where my clean channel had this really cool slightly overdriven sound going (no I wasn't using the 'pushed' setting'). Anyway, I swapped in some brand new Mesa tubes, and it sounded good again. During practice that night, I noticed after playing a bit that the sound was immediately going downhill again. The next night, I decided to test it out again, this time cranking it up to push the tubes and observe. Essentially, all hell broke loose immediately. The tubes started flashing and the fuse blew before I could reach over to the standby switch. It smelled. Brought it to the shop, it had a good hum even on standby. After the repairs were completed, the techs told me that what appeared to have happened was that a tube went bad at some point and overheated and melted out a resistor. Since the repair, I can still smell the same odor from the night it failed, not as strong and presumably from the incident. The amp has played pretty well since, though, will the exception of some microphonics, which I think I have narrowed down to the FX loop. I've also been alerted that all pre-amp tubes can have issues with microphonics, it doesn't necessarily mean a tube is toast. The pre-amp tubes are only about two months old, at the most.

[Mouthurst]

Ive seen this before-bummer-Sounds like you need a surge protecter-- a small ac surge in the building where youre playing can be a big one in an amps circuit-I use a 5amp one with 4 outlets and a built in reset button-works great.
And yes I have had to reset it a few times.
Worth a shot.