Plinius is famous for waking up speakers and delivering dynamics you never thought they had. Drum hits and bass plucks jump out as they should yet the SB 301 MkII still delivers the micro dynamics, sound stage and beauty in the overtones that is so hard to get with most solid state. This amp is being sold by the repair and upgrade facility in the US that only works on and upgrades Plinius. We are experts in all Plinius models. This unit has received a more robust hi speed power supply by us with remarkable results. It is important to say this amp did not have a problem nor is it "B" stock. It was part of an experiment to further improve the already great dynamics into the very biggest speakers in the biggest rooms. We were not surprised to hear the sound improve across the entire range. This mod is now part of our upgrade and improvements to all Plinius models upgraded by us. Much more info about this and a long list of customer comments can be sent if you call us. 716-688-3527. The amp is new. All offers considered.