Pre/Power Amplifiers

Our first exposure to Emotiva's exceptional watt-per-pound value amplifiers came with the XPA DR2 [HFN Oct '18] which is rated at 550W/8ohm and 800W/4ohm but, on test, delivered 650W/8ohm and 1.02kW/4ohm. The XPA DR2 uses two of Emotiva's amplifier modules in bridged mode with a derivative of the switchmode PSU that we see in the XPA HC-1 tested here. However, the HC-1 uses one amplifier module per channel in single-ended fashion and so, without the voltage headroom of bridging, it supports a lower 220W/415W output into 8/4ohm but exactly the same 32A current before its electronic protection kicks-in. So the DR2 offers 2060W/2ohm and the HC-1 an 'equivalent' 1035W/1ohm [see Graph 1]. Few other £800 amps will support 1kW/1ohm, so this is a very load-tolerant monoblock.

Graph 1 also illustrates a more fundamental difference in the behaviour of the HC-1's single module where distortion is highest at low power output (and typically 3rd, 5th, 7th odd harmonics) before decreasing as power increases, from 0.045%/1W to 0.015%/10W down to the rated 0.005% from 100-200W (all at 1kHz/8ohm). This trend, plus the general uniformity of distortion vs. frequency at moderate power is also clearly illustrated in Graph 2, below. Overall gain matches that of the DR2 at +29.3dB (balanced in) but noise is slightly higher and the A-wtd S/N lower at 86.5dB (re. 0dBW). The response is also unchanged over the DR2, rolling gently away at HF to –0.45dB/20kHz and –5.4dB/100kHz, just as the output impedance holds to a steady 0.04ohm from 20Hz-5kHz, increasing gently to 0.065ohm/20kHz and 0.34ohm/100kHz. PM