Audio Research D-250 MK II Servo

This was the last version of the D-250. It has very low hour Svetlana Wing C 6550 tube purchased from the Tube Depot and are considered NOS . The tubes are still available from tube depot. Face plate has no scratches or dings. The main power transformer has scratches as shown in picture. The S/N is #23430016. Amp sounds wonderful and deserves a good home. I am selling it only because I am downscaling. Lived in non smoking environment. All coupling capacitors have been replaced with New RTX Multi Caps that are film and foil polystyrene, this made a quite an improvement in transparency of the amp. I'm sure William Johnson would have used this technology had it been available at the time! The "Servo" enhancement is basically just a means for stabilizing the DC balance between the two halves of the input stage. That may not sound like much, but it's a very important factor in minimizing changes in the amplifier's performance characteristics as the tubes gradually change during their operating life. Here is what Stereophile had to say about the D-250 MK II Servo: But the D-250's most overriding virtue is the sheer musicality of its sound. Everything about it has an intrinsic rightness to it that makes it difficult to concentrate on anything but the music. There is nothing to call attention to the fact that one is listening to a reproduction rather than the real thing. Much of this effect can be lost if the speakers aren't up to snuff, but when they are, the D-250 comes through as an almost perfectly neutral device. This, of course, is exactly what we ask of any amplifier, but the Audio Research D-250, like the incredible SP-11 preamplifier, comes about as close to achieving it as any amplifier I've heard.