a demidoff integrated... a huge amp. i listened to it for around two months, and though it did everything right, i couldn't see keeping it. i was looking to displace my revox stuff, which i do from time to time, in weak moments. it powered castle harlechs and gradient revolutions. as far as sound goes, i would compare it to an electrocompaniet, or primare(smooth as silk) ...which is a complement. my only concern would be service....not because they are known to be troublesome, but because their presence in the US is minimal.