Pre/Power Amplifiers

As I discussed in our review of Chord's flagship Ultima monoblocks [HFN Feb '19], 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 to double the amplifier's voltage capacity. Chord takes a different approach, its Ultima 2 sharing the same trio of ±110V switchmode supplies debuted in the flagship Ultima, operating in parallel here to deliver the current required to maintain the amp's voltage output across very low loads.

So, like the Ultima, the '2 bucks the industry trend for bridged output stages, making these two amplifiers the most powerful single-ended hi-fi designs in the world. Furthermore, the fact that the Ultima 2's output stage is half the size – 32 lateral MOSFETS instead of the Ultima's 64 – has very little impact on its real world performance. In practice, it's the three PSUs calling the shots here – supporting dynamic outputs of 825W, 1595W, 3041W and 5617W in the Ultima and 810W, 1590W, 2963W and 4850W into 8, 4, 2 and 1ohm loads, respectively, for the Ultima 2. So while the Ultima delivers a clean 75A of current for short-term musical peaks into the toughest loads, the Ultima 2's 70A is no less impressive.

The most powerful amps we've tested? Up until the advent of D'Agostino's Relentless monoblocks [HFN Mar '20], that crown was 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 continued to 8820W into 0.8ohm. But the £250k Relentless – another balanced/bridged design – has set a new benchmark with 1740W, 3350W and 6360W into 8, 4 and 2ohm and 11,325W (or 106A) into 1ohm. Astonishing, but at a price! PM