I hate to say it, but now I think maybe I like my amp in ultralinear mode versus triode

With the tube amps I’ve owned that can switch between the two modes of operation I always ended up preferring Ultralinear mode,mirroring your findings of better imaging definition,slightly forward staging & more "meat"on the bones in the bass & upper bass...I do however believe this is speaker dependent..All of the speakers I had at the time were already naturally warm sounding(Harbeth M30.1,Fritz Carbon 7SEMk.II & Sonus Faber Lumina III),negating the benifits Triode mode provides...With a speaker that has some tendency towards a more lit up-forward tone(Triangle-Kef-Klipsch or anything with metal drivers) I think Triode mode might be the way to go...

I prefer my Cayin A-88T's ultralinear 45 wpc to triode 22 wpc. My horn speakers are very very efficient, so I do not think it is related to the extra power, there seems to be a fuller more natural sound, similar to the change from 6550 tubes to KT88 tubes.

@mulveling 

There’s some paranormal audiophile force that makes us feel like the more "purist" approach must always be better: triode versus pentode, DHT versus separate heaters, single-ended versus push-pull, ladder-dac versus delta-sigma, discrete circuitry versus opamp / IC, lower output MC versus higher, single full-range driver versus multiple etc. However, when we shut up and actually listen, we can plainly see this isn’t always the case - and certainly, preferences play their hand heavily here.

Thank you for saying it. This was my initial thought. It's easy to take the consensus opinion even when it may be wrong. I suspect we all have done it about something. But it shows the importance of testing everything for ourselves.

@immatthewj 

Well, I guess because for nearly 23 years I steadfastly maintained that triode sounded more refined and also "more better." Perhaps I was wrong about "more better."

I was just pulling your leg. Its a bad habit I have.

@decooney 

@immatthewj you were pretty close on your thoughts and memories of the Mesa Baron amp. Appears that amp delivers 150Wpc in full pentode mode, 120Wpc in 2/3 pentode, 85Wpc in 2/3 triode, and 60Wpc in full triode.

Ask: so, which of the switch modes did you enjoy most with the Mesa Baron amp?

If I may suggest, there might be a "next chapter" for you in your discovery, possibly moving to now try a (non-switchable) dedicated Ultralinear amp(s). Then trying a dedicated (non-strapped, true single ended) Triode amp with actual Triode tubes. 

I found that issue of Stereophile, and what a looker that amp was!  Dual monoblocks in one chassis, rack handles, meters, switches, knobs, a dozen output tubes . . . that, unfortunately, was probably a lot of the reason I was initially intrigued with it.  (A guy I used to work with used to say I was like the Indians who sold Manhattan for some shiny trinkets.  He may have been somewhat correct.)  Anyway, Anyway, I also found the flier from Mesa for The Baron that the dealer gave me (I had the flyer inside the Stereophile) and Mesa was saying that the amp utilized "pentode."  As far as which mode I preferred, well, I spent very little time in full triode or full pentode, most of the weekend was spent in 1/3 triode 2/3 pentode per dealer's advice, and I actually was intrigued and initially liked the presentation until I did the A/B I typed about.  At the time, I was using a B&K digital HT (prologic back then) preamp, and I had a dealer in Philadelphia who had set me up with that first system (the B&K and the SLA70) and I talked to him about the experience and maybe upgrading to a pair of SLM100s to get the sound stage without the "smokiness" and he told me (and I will have to paraphrase) that 'the Baron is a chameleon'  I do remember he did use the word "chameleon" and the sound I heard was due to the level of preamp.  Which may have been true.  But I didn't buy SLM100s from him.

What I did do not a whole lot later was to buy (through the classifieds in the back of Stereophile)  a secondhand pair of ARC VTM120s, four 6550s each, 100 wpc in NONSWITCHABLE UL.  And I like those ARCs, I really did; they would rock out (and I mean ROCK OUT) or whisper . . . and it was CLEAN sound and that was with the B&K in front.  And then, another aside, but still another local dealer had a second hand modded SLP90 that I took  home for a weekend, and then and there I learned the difference a preamp can make.

The reason I didn't keep those ARCs (I still have the SLA70, btw) is that they had a random habit of blowing a grid resistor on start up.  And taking one of them down and desoldering and resoldering grid resistors is no way to start a listening session.  I used to grit my teeth and cross my fingers when I flipped the switches.

Anyway, when Sterophile reviewed the V12 I was intrigued by the switchable from triode to UL feature and I knew that back then (in the Dennis Had/Kirk Owens days of Cary) I found my SLA70 to be reliable and Cary's tech support (when needed) was superb, so I took the plunge and bought a V12 from a dealer in Colorado, sight unseen.  

And that's how I got to the V12.

Thanks for the great post, and with your V12, did you roll any tubes besides the EL34s?  Like 6550s for example?  I do note that in the owner's manual, Dennis Had was saying one could do that.  I have about three good quads of 6550s for my SLA70 (six of NOS Tung Sols 6550 from Andy in Michigan, a quad of Svetlanta 6550Bs,  and I think a quad of KT88s, but I'd have to look to be sure, hat were branded "Tesla" that I got from Audio Advisor).  I was thinking of possibly biasing the amp for two tubes aside someday, and trying it in UL with 6550s?  I tried four tubes aside once back in '18 or '19, but I have to confess that this was back in the days when I was swearing by triode, and I wasn't crazy about it.