Audio Research Ref 110. Fabulous sounding tube stereo power amplifier. Balanced inputs. Excellent condition. Little used, approx 1,000 hours on tubes. Review: Audio Resurgence What Makes The Ref 110 Special? It has an effortless presentation and never holds back on loud complex passages. It presents detail but given adequate warm-up time and suitable ancillaries, the detail is never etched or clinical sounding. It has a large enveloping soundstage, particularly front to back, with good image placement and plenty of air and space around elements in the soundscape. It provides a good, solid bass foundation, better than most tube amps that I’ve heard to date. It is remarkably transparent. Speakers are able to disappear unimpeded and the window into the music is clear, without any discernible opacity. It has dynamic drive and punch and is great with rock music, but if the recording is bad, it isn’t going to gloss over the fact. Review: Stereophile The Audio Research Corporation's Reference 110 amplifier replicated, over many weeks of listening, the magic I'd experienced in those few hours of listening at Home Entertainment 2006. In certain areas the amplifier produced a level of realism startling enough to make me reluctant to turn the stereo off. I had this experience with all types of music, as well as with movies. Although the 110 was an excellent match for ARC's Reference 3 preamp, I didn't need an ARC preamp to hear its magic.