Triode or Ultra-linear? Why?

Tablejockey,
Yes, the Baron can be run in all-pentode mode, but the sound it a bit harsh.  Don't know why.  I don't think anyone used them in all-pentode mode for long. 

Wolf, one rumor I heard was that Mesa got tired of dealing with the demands of audio dealers, who wanted frequent "upgrades" to be made available.  

@lloydc A good friend had an inside relationship with the folks at Mesa, and used a Baron for a while.  Mesa got out of the high-end audio business due to a lot of "advice" coming in regarding how to build an amplifier, especially in relation to a severe lack of $$$ coming the other way.  This isn't a hobby to them, and this market just didn't make business sense

I get that and I am amazed how many amps Mesa has made over the years, from Prune Music modded Princeton Reverbs, to every possible tube amp style and so many current models I can’t keep track (I had a Mesa Boogie combo amp in the early 80s that had a 15" Altec in it…weighed a ton)…the Baron was a surprise and at the time I wondered what the hell they were thinking with such a complicated stereo amp, but it was cool anyway.

You’re right WOLF. Some of the best guitar amp implementations of the major players.

My friend looks like the typical go through audio components like socks audiophile. But when he got the Baron, he told me his wife said, "Throw the box away." Yeah, right. The next time I visited he had an Antique Sound Labs 1006 that ran 2 X 845 tubes. Personally, I thought that amp sounded better in his system than any he’s had before or since, but the Mesa impressed me a lot as making too much sense from the standpoint of flexibility, build quality / reliability, really good sound, and it was sensibly priced