Regarding A/B'ing the Tenor OTL's and hybrids, I did that in my home over a 2 week period when I had both amps.Contrary to what I've heard others say, and I'm not sure how many of them actually had both in the same system or heard them in different systems which isn't a fair comparison, I felt the 300's were superior. The midrange magic that some feel the OTL's had over the 300's is simply not the case in reality. The authority and significantly better botton end of the 300's balances the 300 across the spectrum, so the although the midrange magic is still there, it merely doesn't stand out as much as it does with the OTL's, relatively speaking. In my system, the DarTzeel is even better, same midrange magic that comes out of an even blacker background with virtually no noise floor, excellent extension at the frequency extremes, and a palpability that I'd not previously heard in a solid state amp, and very few tube amps. It competently heandles all the audiophile requirements, but more importantly is easily forgotten once the music starts and stands aside for the music which, to me, is its greatest attribute.The Tenors are some of the finest amps out there, and I could easily have lived with them for a long time. But the DarTzeel is magic.