Pre/Power Amplifiers

Achieving high power outputs into moderate 8 or 4ohm loads is as much about delivering a high voltage across the load as supplying the current to support it, which is why most designers opt for a bridged-mode output configuration, doubling the amplifier's voltage capacity without complicating the PSU. Recent examples include D'Agostino's Progression Mono [HFN Jun '17] and Emotiva's XPA-DR2 [HFN Oct '18], achieving 640W and 650W/8ohm, respectively, on test.

By contrast, the architecture of Chord's ±110V switchmode supplies allows three of them to operate in parallel, thereby ensuring the Ultima is one of very few single-ended amplifiers available in this stratospheric power range. Furthermore, as we'll discover, these supplies are so tightly regulated that the Ultima's output nearly doubles into each halving of load impedance – right down to 1ohm where it sings out to the tune of 5620W, or a clean 75A of current for short term musical peaks. The most powerful amps we've tested? The crown is still held by Musical Fidelity's Titan [HFN May '10] and Tri-Vista kW [HFN Aug '03] – bridged designs that delivered 1050W and 1996W into 8/4ohm loads, the former achieving 5896W/1ohm (76.8A) while the Tri-Vista kW went on to drive 8820W into 0.8ohm, supported by over 100A! PM