Triode or Ultra-linear? Why?

Several months ago I added PrimaLuna Prologue Mono-block amps and Preamp to my system. Of course, I keep fiddling with the Triode/Ultra-linear switch, It's so easy since it's on the remote. Can't decide which I enjoy most. Leaning toward triode. What's your experience? 


For R&R, UL  seems to be the preferred mode, since you want a little extra umph for the drum/bass. Typically any instrumental-R&R,Jazz, Classical I leave my PL in UL.

Jazz vocal divas-Ella,Billie, Sarah..etc I prefer triode, which "pushes" the band further behind the vocalist.

If I had to choose only one, I probably would choose triode.

Tablejockey, thanks for your response. That's exactly where my ears seem to be taking me as well.
+1 @tablejockey , Who describes the trade-off precisely. I prefer the lower distortion of triode, even with the slight reductions at frequency extremes, with my Mesa Baron, for virtually all music except loud rock.  
Ultra linear is supposed to have similar linearity to triode, but in my experience, there is no substitute for actual triodes.
lloydc-I heard the Mesa years ago, isn't there an option to run full pentode as well? 

From what I remember, the Mesa is a fine piece, just like their guitar amps.

I have Triode / Ultra Linear mode switches on my MonoBlocks. I like Triode Mode better. Midrange detail is better. I guess it depends on the speakers you are using do to lower power output.
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Very interesting. Most posters seem to enjoy triode mode. Why not just make a superior triode amp, save the cost of switches and additional wiring? Actually, I think I know the answer. Most consumers are impressed by power ratings, nothing else.
The only tube amps I've gotten along with have been pentode/UL. SE, yet to hear a PP. As you likely can guess I mostly listen to metal, classical, and electronic music. Frequency extremes are important.

I agree on dedicated amps without switches, I like purpose built equipment. Too many options seem to me like a lack of direction from the manufacturer. There are plenty of SET fans out there, I don't see them missing the switch. And it's kinda neat to see what you can pull off with really low power amps, I'd be tempted if it wasn't for the mid-range focus of much of these amps
I had a VAC amp that was switchable from ultra linear to triode and always preferred ultra.  Triode was too soft and lacked dynamics even with my ESP speakers which present a tube friendly load.  Now I have a BAT amp which is only triode and lacks nothing in drive.  I don't believe the switch option provides a fair comparison.  Pure triode sounds awesome at the expense of inefficiency and massive heat. 
I find my lofi tubed system absolutely needs the UL/triode option. The majority of my listening is records, many are simply too "hot" when cranked 
ocaissionally in UL. Hearing a Les Paul or cymbals at near concert levels isn't the same when I heard the same song 40 years ago.

UL for me is also a "loudness" switch when listening at low volumes.

I suppose  actual system configuration also,determines what you like.

Presently listening to SD "Katy Lied" in triode. Sounds pretty good for an album they hated for its SQ.

After decades of tube and SS stuff I'm way into a Dennis Had single ended pentode amp now ("Fire Bottle" HO, ranted about by me frequently…sorry... ), and although you should use it with relatively efficient speakers to enjoy all the 12 watts each side offers, I doubt I will ever go back to anything else…as with any great amp (used properly) it doesn't care if it's called on to pump out Steely Dan (I still have all my 70s vinyl), or Benjamin Britton or acoustic jazz…everything works, and surprisingly at all the loudness I seem to need…a great low volume sound also, and other than turning my 2 REL subs up or down here and there I have no tone controls (my DAC has filter options, but that's it). Katy Lied indeed, and I like it.
Also, I think tube guitar amp companies should all consider making a little stereo amp…that Mesa Baron was so cool, and if you can buy a USA (Kentucky) hand made tube rectified single ended class A tube (EL84s) amp head like my 18 watt Burris Royal Bluesman (it's royal blue…get it?), which includes a preamp section and spring reverb for around a grand new, these guys are missing the audio geek boat, so to speak.
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