New setup: question about tubes for Mesa 2:90

[laurens]

Two weeks ago I switched to building a rack. My new set up is now: Engl E530 (preamp) -> TC Electronics G Major 2 -> Mesa Boogie 2:90 -> 1960AV (with G12-K100's). This is really capable of some super fat metal tones. I bought the Mesa 2:90 used but I don't know how old it is. The plate on the back says to use 6L6 GC's. Currently it has Sovtek 6L6 GC tubes in it (from the previous owner).

 

I guess I need to retube the Mesa 2:90 in the next few months. So HCAF, what brand of tubes would you recommend? Furthermore, I read on the website that the 2:90 has a fixed bias. Probably a stupid question, but does this mean that there is no need to rebias when puting in new tubes?

[Cap'n'Budda]

Sadly, no, it doesn't mean no need to bias. But it does mean you can't bias without a mod to add a bias pot. Mesa's philosophy is to match the tubes to the amp rather than the amp to the tubes.

 

The easiest but most expensive thing to do is to get Mesa to sell you the right tubes that will match the existing bias point. The second easiest thing to do is get someone like Eurotubes to sell you the right tubes. The hardest thing to do is to have the pot installed, use any quads of tubes you like, and you (or someone else) bias it.

[dmtnt]

Call Doug's tubes or Eurotubes (prefer Doug as he carries more than just JJ's) and tell them it's for a 2:90, they'll give you the right grade of tubes.

 

My favorite tubes to date in my 2:90 have been JJ 6L6GC's in the Class A/B slots and Winged C 6L6's in the Class A slots. You can also try EL34L's in the Class A slots provided you get a really hot matched set from Eurotubes.

[starsnuffer]

I've a 2:90. IMHO, there really isn't enough coloration in the sound of this particular poweramp to warrant tube change experiments. Your best bet is to remove a tube, see what kind it is (str 420 or whatever) and then call up Doug at Doug's tubes to see if he has two matching quads that would work with that. You could also just get the mesa branded tubes from a mesa dealer.

 

-W

[laurens]

 

Sadly, no, it doesn't me no need to bias. But it does mean you can't bias without a mod to add a bias pot. Mesa's philosophy is to match the tubes to the amp rather than the amp to the tubes. The easiest but most expensive thing to do is to get Mesa to sell you the right tubes that will match the existing bias point. The second easiest thing to do is get someone like Eurotubes to sell you the right tubes. The hardest thing to do is to have the pot installed, use any quads of tubes you like, and you (or someone else) bias it.

 

 

Thanks for the reply. Do the Sovtek 6L6 GC's match the current bias pot. In other words, is it safer and easier to buy these tubes again (I assume all Sovtek 6L6 GC's are the same)?

[starsnuffer]

 

Thanks for the reply. Do the Sovtek 6L6 GC's match the current bias pot. In other words, is it safer and easier to buy these tubes again (I assume all Sovtek 6L6 GC's are the same)?

 

 

No, that's why you have to call Doug and tell him what you have so he can send you the right tubes. All tubes bias differently. Mesa tests tubes and labels them to match particular amps. People like Doug do the same thing, only with a wider variety and often higher quality tubes then mesa uses.

 

-W

[Cap'n'Budda]

 

Thanks for the reply. Do the Sovtek 6L6 GC's match the current bias pot. In other words, is it safer and easier to buy these tubes again (I assume all Sovtek 6L6 GC's are the same)?

 

 

Unfortunately, it's not by brand. Within a given brand different individual tubes will need different bias settings. Since you bought it used there's no guarantee those tubes are even right.

 

Tube companies test their tubes, and have rating schemes that tell them what tubes will match what bias settings. They then match similarly rated tubes up into matched pairs and quads. Since the 2:90 is fixed bias, tube vendors who deal with mesa a lot (or who ARE mesa) will know what rating will work with it. Mesa, Doug's Tubes and Eurotubes are all perfectly good options to get what you need.

[laurens]

 

No, that's why you have to call Doug and tell him what you have so he can send you the right tubes. All tubes bias differently. Mesa tests tubes and labels them to match particular amps. People like Doug do the same thing, only with a wider variety and often higher quality tubes then mesa uses. -W

 

 

OK, thanks man. I will check that one. The Mesa tubes will always fit, right?

[starsnuffer]

 

OK, thanks man. I will check that one. The Mesa tubes will always fit, right?

 

 

Mesa 6L6's come in two strengths, as I recall. This will be labeled as "STR XXX". Just pull an old tube out and look at it, they should all be the same if it has the original tubes. When you order from a mesa dealer, just order the same thing.

 

-W