The amp was up and kept running 4hrs/day for 2 weeks. This amp is indeed very good. Being dynamic, detailed, and a bit of "tubby" sound, I like it very much.
BTW, I some times wonder if it's possible to use the new-designed KT family as the output stage. BH use EL34 as triode. Though EL34 is pentrode and KT77 is beam tetrode, I thought they were almost identical(working). The new-designed KT120 or KT150 can handle a little bit higher voltage and much bigger current output. So if it's possible to use KT120/150 as output stage, maybe there's no need to use current amplification like ciclotron?
Plus, using dht tube like 300B/845 may have humming problem. So maybe using KT family is better?(though the voltage is lower....)