11-16-10: Pearlaudiohi Just found some info and it confirms the MKII uses the solid state j-fet input. The original uses the 6922 tube as the input driver. Did anyone ever compare the two?
11-16-10: Rrog AR stands for Acoustic Research. You must mean ARC.
Besides using J-FET drivers power supply regulation is also improved.
I'm not aware of an Audio Research MKII that isn't a genuine improvement. Rrog (Answers | This Thread)
11-16-10: Jafox I would take the 6922 input any day. And remove the Sovtek tube, throw it in the trash and try out any number of tubes such as the Telefunken, Amperex PQ, Valvo, etc. Jafox (System | Reviews | Threads | Answers | This Thread)