This is interesting for the idea of using a HF carrier to reduce the transformer size. Not really new, actually very old, but I have not seen it applied to an audio tube amp in many years. Otherwise it seems a fairly average tube amplifier. And of course the reviewer takes a healthy swipe at objectivists (sigh).
https://www.stereophile.com/content/linear-tube-audio-zotl40-mkii-power-amplifier
https://www.stereophile.com/content/linear-tube-audio-zotl40-mkii-power-amplifier