Tube Amp settings: Triode vs UL; 8 ohm vs. 4 ohm ?

I believe that the triode setting will enhance the mid-range whereas the UL is more linear in freq response. That may help you to know what to listen for. There again, this is the theory.

Good greif! 

YOUR EARS are the judge. It's not technical. Whatever sounds good to YOUR EARS.

Thanks for responding. I should also say that perhaps consideration should be given to my Micro 3000 SVS Sub, related to the Triode vs. UL switch? As some will know the Sub settings are “ on the fly now with SVS installing their App on your phone?

A lot of people prefer triode operation over ultralinear for sound quality (smoother, less brittle sound), but the cost is lower output.  I have only heard a few amps where such a switch can be made for a direct comparison and I don’t recall liking triode operation that much more than ultralinear.  Again, give both a try.

(On a different amp) I was expecting to like triode better the UL, but that was not the case as the bass was thin. But the vocal were more airy in a nice way using UL.
(the beauty of a switch is it is easy to try it.)

Maybe another amp driving the woofers would be a thing for me to try.