@charles1dad fyi, fwiw. Between my former Cary SLI-80 and Cary V12 amps, Denis built me an Inspire Hot Rod with KT150s. He really wanted me to try it given my past with his former Cary designs. I used my Cary SLP-98 preamp to drive it for about a year. Still use the same preamp today, like it quite a bit for my needs.
While the smaller Inspire amps were a little better at mid-volume levels, it never quite drove my 6ohm 93db sensitive speakers properly at low volume levels. Kept my Cary 6SN7 preamp and, re-sold all of the Cary Inspire amps. On to the next Mono amps I went. I share this as those amps are sensitive to speaker selection.
Next:
Due to my speakers not being ultra efficient or closer to stable 8ohm higher impedance, I had to try something else, more, different - it paid off.
Moved to larger Quicksilver Mono 120s with the much larger and higher quality transformers. For my own reasons to compare apples-to-apples, I upgraded to much higher-end coupling caps and a better small signal input/driver tube set. Much-much better drive and clarity at low volume listening levels (night time listening). After the cap and tube upgrades, boom, game over, done. Never looked back. The new QS KT Monos are sweet, more versatile for speaker matching. Simply put a great triode preamp in front of them, and the result is high value.