Integrated Amplifiers

Succeeding the H120, the H150’s analogue amp section can also trace its technical DNA back to the 60W-rated H95 [HFN Oct ’20]. Like the H95, the H150 is most comfortable driving 8-4ohm loads where its 75W spec. is exceeded to the tune of 2x90W and 2x140W, respectively, and where there’s sufficient headroom to sustain 126W/8ohm and 216W/4ohm under dynamic conditions (all <1% THD). However, with just a pair of output devices per side and a relatively modest PSU, the H150 has wisely been current-limited to just 18W/1ohm [Graph 1, below]. Otherwise the H150 retains a sensible +31.5dB overall gain (XLR input) with an improved, above-average 90dB A-wtd S/N ratio (re. 0dBW) and a response tailored to ±1dB between 5Hz-75kHz (–1.5dB/100kHz). THD is low, increasing gently with output from 0.002%/1W to 0.003%/10W, 0.005%/40W and 0.03% at the rated 75W (all 1kHz/8ohm). Versus frequency, THD only increases at the extremes – 0.006%/20Hz and 0.028%/20kHz (re. 10W/8ohm).

The streaming board is based on that in the H400 [HFN Oct ’24], albeit with an AKM AK4493SEQ ‘Velvet Sound’ DAC in place of the ES9038Q2M in the digital section. Hegel’s own upsampler and linear phase filter offers a 102dB stopband rejection with a response that shows a mild but consistent HF lift with all sample rates, reaching +0.2dB/20kHz, +0.75dB/45kHz and +0.9dB/47kHz (–28dB/53kHz) with 48kHz, 96kHz and 192kHz files, respectively. THD is 0.002-0.02% (20Hz-20kHz) with peak (0dBFs) inputs and falls to a minimum of 0.0004-0.0015% over the top 30dB of its dynamic range [Graph 2]. The 101dB A-wtd S/N ratio is a little below average [but see p85] while jitter is very low at <5psec. PM