Tube Newbie With A Problem

[cjack]

I just received a Mesa Simul 2:90 I bought on eBay. In theory, it is "new" and with a transferrable warranty. Seller had lots of good feedback, so what can I say? He's agreed to refund my money if I return the amp. If it's just a tube, it was a smokin' deal, so to speak, and I'd hate to have to return it.

I am a tube newbie, but from what I read here my problem may be tube-related.

When I first powered up, the amp simply did not make any sound. :x Powered up , all tubes glowing, fan on, but nothing save for an occasional crackle. Uh oh, I'm bumming. I called Mesa and the tech said check the fuses on the I/O panel. Both fuses were cooked. I called Mesa back and the tech says sounds like a bad power tube. Pull the tubes and smell the end; if it smells burnt, there ya go. I pulled all tubes, no telltale odor.

I bought a couple more fuses and fired the amp up. It was playing and I must say for all of about three minutes, sounded great. I smelled something burning and a fuse blew. No smoke. The shipping box looked intact and the amp was well-packed. I see nothing amiss inside the amp - looks pristine.

Man, I'm hoping this is just a bad power tube. One of the tubes looks a bit discolored relative to the others. They all seemed to have the smae glow. Anything else to look for? Can a tube have a short and smell like it's burning?

Wonder if Rat Shack has a tester. :?

 

[no soul]

are you sure your speaker interface cable is good, because a bad one can lead to the problem you are having.

And if you even remotely suspect the tubes are going, just go ahead and buy new ones. If turns out it WASNT the tubes, then its not like you wont be able to use those tubes down the line.

 

[cjack]

are you sure your speaker interface cable is good, because a bad one can lead to the problem you are having.
...

Yes, new speaker cables that were working fine with another amp.

 

[cjack]

Next question:

If I replace a Mesa tube with another brand, do I need to replace all lthe Mesas? Is it a bad idea to mix brands?
Man, those Mesa tubes are expensive.

 

[pau_leader]

Next question:

If I replace a Mesa tube with another brand, do I need to replace all lthe Mesas? Is it a bad idea to mix brands?
Man, those Mesa tubes are expensive.

I would just buy the same brand with a matched set. Try not to buy tubes seperate.

 

[musicbox]

more clearly:

DO NOT MIX POWERTUBES

if you replace one, you have to replace them all. they must be matched.*

you do NOT have to replace the pre-amp tubes when you replace the powertubes though. these will go at longer intervals(1-2 years in a highgain mesa, maybe longer in a poweramp), and the amp will still work when they are on the way out, it'll just sound like crap.

if you have the money, there is no hurt in just replacing them becuase there is only 3 of them.... and youll know that there is fresh tubes in it.

if you are going to use tubes that are NOT mesa-boogie, make sure you go through a reputable dealer that can grade and match your tubes to your 2:90. www.thetubestore.com www.eurotubes.com www.bobstubes.com

good luck!




*theoretically you can replace just 2 of the tubes, either the outside pair or the insided pair as long as they are matched correctly, but i dont think this is a good idea, plus you don't know which tube is gone. best to just retube in matched quads.

 

[cjack]

How about this question:
Can a tube have a short and smell like it's burning?

 

[NoGlassNoClass]

How about this question:
Can a tube have a short and smell like it's burning?

Never really noticed a smell from tubes...the fuse can smell when it blows, and 90% of the time blown fuses=bad tubes. Tubes can have intermittent shorts that may not even show up when tested, but rear their ugly heads when playing due to vibrations and such.

For less cash out, and tubes of equal (or better IMO) quality load that puppy up with some JJ's (www.eurotubes.com)

You can get tube-testing and matching equipment from www.vacuumtube.com and www.maximatcher.com but its cheaper to just get new tubes.

 

[cjack]

...
For less cash out, and tubes of equal (or better IMO) quality load that puppy up with some JJ's (www.eurotubes.com)
....

That's exactly what I'm gonna do. Tubes on the way...