Gents,
I have had the amp running for most of a week, now powering my Spatial M4 Triode Masters. I had a musician pal come by last weekend to listen to some music. He knows my system very well and noticed the difference right away with the new amp controlled by my Sachs preamp. The music seems so alive and realistic that I listen for hours, just palpably real. Driving the Spatials as loud as I could tolerate, there was nary a hint of distortion or breakup. If the amp doesn't capture the top of the top end, it is not a bother as my ears don't hear much above 9 kHZ. The mid-range is just sublime, warm and seductive. Reliability aside for the moment, I will go out on a limb and say that this amp is very near the top of my list of reasonably-priced audio gear that delivers on its promises (at the top of the list is my Oppo 103D). This amp needs the proper speakers to perform its best... as Charles said above, "The more efficient the speakers, the better the results." As with the 6SN7's, there is real magic in 300b tubes. Heck, there is magic in all tubes! If the Class D designers can reproduce this sort of sound, then they are really on to something. My VTV Audio amp with the Purifi module, while very good, sounds nothing like this Willsenton amp.