"The stasis circuit developed by Threshold , guarantor for load-stable power supply in the low-impedance power range, worked in the well-known power amplifiers, and in the flat receivers! The SR-2,3 and 4 receivers, the SR-4 even remotely controllable, had a good sounding phonosection (the 2er unfortunately only MM) and of course an excellent tuner built in. In terms of sound, these parts tend to a natural, rather deep and wide, rather than high stage. An SR-4 sounds much more natural than, for example, an Accuphase E-206, which plays louder and bigger, but much more unmusical. Details are wonderfully resolved with the emphasis on the subtleties and structures, analytical in the best sense. ... are easily adjustable, just no debris. ... If you get your hands on a semi-neat device today, after more than 20 years, they run flawlessly. A manufacturing quality that the Europeans and Americans were running after! ... the newer ones from the series Amp 1, 2 , Receiver 1,2,3,4 and CD player with music bank system. This series is often talked about badly, because it is produced in a time of the declining HIFI market. Despite the use of sometimes simpler components, these devices are excellently processed, well designed and make stress-free music! More than many devices from that time. The amplifiers with the amplification principle developed by Nakamichi himself are musically, warmly and bass-strong tuned, due to the absolute primacy of the CD- at that time. Unfortunately not quite as load-stable anymore, but still very good! ... "