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

atmasphere said: That’s a bit different from saying that it will ’work’; sure it will play but the output transformer should be optimized for a particular tube.

This is almost certainly the most salient content that this thread will produce. You want to hear great UL sound reproduction? Build an amp that uses KT77 output tubes...the only tube ever produced explicitly to run in UL mode, and specifically at a 43% winding tap and, of course, use output transformers...yep, with a 43% winding tap! As an aside, because the KT77 can handle big current, as long as you specify driver and splitter tubes that can handle big current (like 6BL& or 6BX7) and you use big inductors (on both input and output) to smooth that big current, you can do away with significant capacitance...this yields a very powerful, very dynamic, very fast and very linear, no, make that ultra linear amplifier!

Hate to break it to the assembled, but an amp that can run multiple tube types is not optimized for any of those tubes, neither is an amp that can run multiple topologies optimized for any of those topologies; IMO, an amp that does both represents the antithesis of high fidelity. I avoid them.

"I think use of the word ultra linear is a marketing term and kind of dumb"

Some posters never fail to... Sigh/shoulder shrug

Keyboard  strokes away for basic amp electronics knowledge 

https://www.analogethos.com/post/screen-ultralinear

Like anything, UL and triode will be a bit different with every amp and every system.  With my system with the Dynaco/VTA mods, triode is more refined with a more concise soundstage.  Especially notable with simple vocals, piano, and string, etc.  It's tougher to tell with more layered complex recordings.  My amps are monoblocks, so once in a while for giggles I'll flip one amp to UL, rebalance, and leave the other amp in triode....ultra triode?     

+1 @ozzy62, you said it all. I’ve owned 4 amps switchable between triode and UL, still have 2, and have auditioned a few others in my systems. Each is better in UL. This is true on all 6 pairs of speakers that I currently own, ranging from 86db to 102db. OTOH, I have 2 SET amps that sound better on my high-eff speakers (102, 99 db) than any of the UL amps. The triode option on a UL amp is simply not the same as a purpose-designed SET.

All I know is that on my system some music cds sound better in ultralinear but most sound better in triode.

I’m a big fan of high definition music (Blu-ray audio primarily). Nearly all of them sound better in ultralinear.

i have a horn system with a tube integrated amp fed by an oppo UDP-205 with the Modright magic tube modifications.