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

@dogearedaudio "...anyone with a technical understanding of tube amplifiers (and I’m barely on the periphery of that circle) will shudder at the idea of a "one-size-fits-all" amplifier. ;-)".

To your point, while you can run different output tubes in many of DH’s creations, stemming from his former life with Cary Audio, and recent times creating Inspire, like the early years of Cary V12, V12R, or SLA-70 @immatthewj is referencing periodically - his amps were/are designed and listened to with a very particular output tube in mind. in the case of the V12/R. It’s the classic EL34 tube, paired with particular transformers and input/driver tubes that make for an interesting blend an sound.

Today, If you splurge and buy one of Dennis’ small and more recent 300B amps, you buy it with the new re-issues WE300B tubes, and you pay a bit extra for it and that’s how the designer likes it and wants it to be. Only comes with these tubes.

Falling on my own sword, my existing mono amps were designed with specific power transformers and plate voltage (650v) and such to run TungSol KT150 output tubes in their optimum operating window. With my speakers, I enjoy both sets but also really like how KT120s sound in these amps. Go figure, lol. :)

FWIW, Gary Dodd, shortly before he died in 2015, was contracted by a very rich person who heard his "Blue Monster" amps:

to build the "best sounding amplifier possible; even better than the Blue Monsters."  What he came up with was monoblocks with 4 KT77 output tubes run in OPTIMIZED ultralinear mode with 2 6BL7 input tubes; custom would massive power supply and output trannies, huge inductors on both input and output stages, 700 volts on the plates and Dueland CAST coupling caps.  He died before finishing the amps.  6 years later, his great friend and talented tube audio builder, Charlie Cocci, completed the two amps.  Charlie, who has been building tube amps for at least 50 years, stated "These are not only the best soundfing amps I've ever built, they're the best sounding amps I've ever heard...and I've heard a lot of amps!"

FWIW.

Those amps are in my living room.  The Dodd Audio Balanced Power Supply that is shown in the 2nd photo powering the Blue Monsters now powers the amps in my living room.

I'm a very lucky person.  Confirmation bias confession?  I don't think so, I think I just agree with Charlie.

FWIW.

@immatthewj

"Zero" feedback? Really? I’ve looked at the CAD-280SA V12 manual online and it doesn’t mention feedback, but perhaps that's a different model. Hard to imagine they use NO feedback. Maybe not global feedback, which encompasses the output transformer. Internal feedback can be used to good effect, but no feedback at all is hard to imagine.

@decooney

Oh sure, there are amps that will work well with different output tubes, and "non-optimized" can offer some interesting sound signatures. Like I said, nothing wrong with that. ;-)

Apologies if this came up earlier in the discussion...Do you guys re-bias and adjust for volume difference when you change between UL  and triode?  UL plays notably louder at the same volume setting than triode on my amps, and I'm assuming others too.

It’s nice to have gear with different sound options. Why be stuck with just one sound unless sure that’s the one you like best.