I had the opportunity to listen to a friend's ARC Ref 1 preamp. His system was very good: Linn Genki CDP, ARC Ref 1 preamp. ARC PH3 phono stage, Linn Sondek LP12 TT with Linn tonearm & Dynavector 17D cartridge, Symphonic Line Kraft 250 stereo amp & Newform Research R645 speakers.
The ARC Ref 1 was a total disappointment in that system. The sound (for all the very nice electronics) was mediocre at best & left a poor impression of such an expensive preamp. FWIW.