Halcro Eclipse Stereo Power Amplifier Lab Report

Lab Report

Much about the Eclipse is truly exceptional, but it is not breaking any audiophile records for power output. Rated at 2x180W/8ohm and 2x350W/4ohm, it achieves 2x210W and 2x370W, respectively, though its clipping behaviour is very abrupt indeed. Class D and high-feedback Class AB amplifiers typically exhibit this type of behaviour, although we are assured the Eclipse is neither! The near-instant clip is readily observed on Graph 1 which shows the 'zero headroom' 210W, 371W and 195W achieved under dynamic conditions, and the current-limited 109W allowed into 1ohm. So the Eclipse is powerful enough, but it won't be giving D'Agostino [HFN Aug '22], Constellation [HFN Dec '19] or Michi [HFN Oct '20], et al, sleepless nights.

However, what Graph 1 starts to illustrate (within the limits of a 10-cycle/1kHz data acquisition) is the extraordinarily low levels of distortion incurred through the Eclipse. THD is reasonably consistent with power output over the rated 180W range and is at its lowest around 100Hz at (best case) 0.00003%, rising to 0.00004%/1kHz and 0.00011%/20kHz [see Graph 2]. These are, by some margin, the lowest levels of distortion I have measured from any amplifier (and I have tested more than most in 40 years!), pushing at the limits of T&M hardware and processing software. The output impedance is phenomenally low ('Devialet-low') at 0.0015ohm (1.5mohm) through bass and midrange, conferring exceptional damping, while the response is a load-independent ±0.1dB from 20Hz-20kHz with –3dB limits of 3Hz-180kHz. The final, and equally astonishing, parameter is noise – so low that it achieves a record-breaking 106dB A-wtd S/N (re. 0dBW). PM


Dynamic power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads. Max. current is 10.4A


Distortion versus frequency versus power output (1W/8ohm, black; 10W, pink; 100W, red)

Power output (<1% THD, 8/4ohm) 210W / 370W
Dynamic power (<1% THD, 8/4/2/1ohm) 210W / 371W / 195W / 109W
Output imp. (20Hz–20kHz/100kHz) 0.0015-0.018ohm / 0.17ohm
Freq. resp. (20Hz–20kHz/100kHz) +0.0dB to –0.1dB/–2.05dB
Input sensitivity (for 0dBW/180W) 190mV / 2600mV (balanced)
A-wtd S/N ratio (re. 0dBW/180W) 106.3dB / 128.9dB
Distortion (20Hz-20kHz, 10W/8ohm) 0.00004-0.00011%
Power consumption (Idle/Rated o/p) 205W / 650W (5W standby)
Dimensions (WHD) / Weight 400x790x400mm / 62kg
Price £40,000 (£46,000 Premium finish)

Halcro (Longwood Audio)
Adelaide, Australia
Supplied by: Sound Design Distribution Ltd, Cardiff
0800 0096213