The Ayre Acoustics AX-5 integrated amplifier, which I reviewed two years ago, was an ear-opening experience. At the time, I stated that “the AX-5 is not only, overall, the finest-sounding amp I’ve ever heard, it ranks as one of the finest components I’ve heard of any type.” The AX-5 featured a technology previously unused by Ayre, called the Diamond output stage, which has since been extended to Ayre’s top models, the R series.