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Ayre Acoustics AX-5 Twenty: $12,950
In 2013, AD described the original Ayre AX-5—a $9950 integrated amplifier built around a recently rediscovered configuration of bipolar transistors known as the "diamond" circuit—as "one of the three best, most musical, most human-sounding solid-state amps I've ever heard." Then, in 2015, Ayre debuted a new version, the AX-5 Twenty—a nod to the company's 20th anniversary—promising even better sound. The AX-5 Twenty is built into the same foursquare aluminum case as the AX-5, and is controlled by the…