This is a rare amplifier is based upon the Marantz PM66 se, and is considerably modified by AH! in Belgium; they also produce the Neu Tjeob CD players. The basic approach is to add a tube stage, in the case they have fitted a high quality tube based preamp. See the link below for a review which gives more details. It is in full working order and has had the tubes up-graded to Russian NOS Navigators. It is 50 watts per channel, and produces a lovely airy sound.