Most other 300B single ended amps turn into dirty, dull mush in the trebles, and have very weak bass. So it comes as quite a shock to hear a 300B deliver the kind of trebles that the PAT-777 does: clean, articulate, fast and extended - yet still delicate, with just a touch of liquidity, softening and rounding treble transient attacks. Bass control is very good in the upper bass, exceptional for a single ended power amp.