FWIW, I've had one of those puppies since they first came out. The amp has great potential but is really system dependent (as is most everything!). Out of the box I think many will find it a bit bright - the critics did for sure, but in an otherwise warmish set up it can be an excellent amp. Mine is up an running as I type. BTW, although the Triode mode is fine, I find the soundstage too diminished and recessed. I run mine in 1/3d triode 2/3d pentode. If I wanted a 'Triode' amp I think I would just buy one designed just for that. I like Triode done right.
I had a factory mod done when it was almost new which changed out the caps to Wima caps, and they help. They also changed out the turn on switches to get them out of the signal path after the unit was running. They subsequently came out with a tri-tube mod which allowed use of 5881's, EL34's, and 6550's.
Right now I'm using it with Silverline Bolero speakers, an ARC SP10 pre, and both a Wadia 302 and a Bat VK D5 CDP's as sources.
I agree with the guys above that recommend that you set your amp up, let it settle in, play with it (all of the options will keep you busy for a while) and see what you think you want to improve.
I wouldn't spend much money on its power tubes but those small tubes make a huge difference, especially if they are the ones furnished by Mesa. Try new production first, like the Mullard re-issues and EI 12AX7E (long grey plates). More importantly, don't overlook the designers comments (in the manual) that you can even use 12AT7's, which have a lower gain. I think this amp works better in a lower gain set up (passive pre-amp or better yet low gain pre-amp). You can even try some in-line attenuators to lower the gain and see if that floats your boat.
Last, but not least, call Mesa and talk to them. They are very service oriented and helpful.
Hope that helps a bit.
