Pre/Power Amplifiers

Whether a misprint or simply devilish humour, Hegel’s original specification for its ‘Master and Commander’ integrated pegged its power output at 301W/8ohm, a very precise figure that’s met in practice at 2x310W and 2x590W into 8 and 4ohm, respectively. That +2.8dB increase from 8-to-4ohm is illustrative of the H590’s massive and tightly-regulated power supply, a reservoir that feeds a dynamic output capability of 325W/8ohm, 640W/4ohm, 1.24kW/2ohm and a huge 2.285kW (47.8A) into 1ohm [see Graph 1]. This power is delivered through a low 0.013-0.045ohm source impedance and a response that’s flat to within –1dB from 6Hz-73kHz (–1.8dB/100kHz). Noise is very low too, the H590’s sensibly ‘low’ +32.6dB gain (balanced inputs) contributing to its wide 90dB A-wtd S/N ratio (re. 0dBW). Distortion is equally low and climbs only gently with increasing output from 0.0015%/1W to 0.0022%/10W, 0.004%/100W and 0.007%/200W through bass and midrange. Versus frequency, THD increases beyond 5kHz although it still only reaches 0.005%/20kHz at 10W/8ohm.

The digital board, based on an AKM AK4490 DAC with minimum phase/fast roll-off filter selected by Hegel, offers very low distortion of just 0.0006-0.00095% (20Hz-20kHz, 0dBFs), with a minimum of 0.0001% [see Graph 2, below] and with response limits of –0.28dB/20kHz, –1.4dB/45kHz and –3.8dB/80kHz (to –24dB/90kHz) with 48kHz, 96kHz and 192kHz media, respectively. The fixed line-level output offers 2.46V from a high-ish 555ohm source impedance, and a passable A-wtd S/N ratio of 101dB with a resolution of ±0.3dB over a 100dB range. Jitter, meanwhile, is impressively low at <15psec. PM

Continuous power (<1% THD, 8/4ohm): 310W / 590W
Dynamic power (<1% THD, 8/4/2/1ohm): 325W / 640W / 1.24kW / 2.29kW
Output impedance (20Hz–20kHz): 0.013–0.045ohm (555ohm, pre)
Freq. resp. (20Hz–20kHz/100kHz): +0.0 to –0.15dB/–1.8dB
Digital jitter (S/PDIF at 48kHz/96kHz): 15psec / <10psec
A-wtd S/N ratio (re. 0dBW/0dBFs): 90.1dB (Analogue) / 101.4dB (Dig)
Dist. (20Hz-20kHz; 0dBW/–20dBFs): 0.002–0.0053%/0.0001–0.0002%
Power consumption (idle/rated o/p): 105W / 1015W (1W standby)
Dimensions (WHD) / Weight: 430x171x445mm / 22kg
Price: £9000