Chord Hugo 2 headphone amp/DAC Lab Report

Maximum output via the Hugo 2’s variable line or headphone sockets is close to 5.2V but the signal is clipped at this point and so the next (lowest) value via its stepwise volume is 4.57V at which point distortion is just 0.0002%/1kHz and 0.0025%/20kHz. Power output is 825mW/25ohm at this volume position, with distortion increased to 0.09% – a figure in line with Chord’s claimed 740mW/33ohm. A sub-1ohm output impedance is key to the Hugo 2 being able to drive low, variable impedance headphones/earbuds without further modification of the overall frequency response. The Hugo 2’s response is influenced by your choice of its four digital/analogue filter combinations and is most evident at higher sample rates. So with 96kHz/24-bit inputs the response varies from 0.0dB/20kHz to –1.25dB/45kHz (Filter 01; 256x WTA), –0.0dB/20kHz to –1.35dB/45kHz (Filter 03; 16x WTA), –0.85dB/20kHz to –4.7dB/45kHz (Filter 02; 256x WTA plus HF filter), and –0.85dB/20kHz to –4.8dB/45kHz (Filter 04; 16x WTA plus HF filter).


THD vs. digital signal level at 1kHz (black, 600ohm; red, 25ohm; 0dBFs = 825mW and –29dBFs = 1mW) and 20kHz (cyan, 600ohm; blue, 25ohm)


High resolution 48kHz/24-bit jitter spectrum (unchanged between line and headphone outputs)

Meanwhile, under headphone loading, there’s a very mild increase in distortion, the Hugo 2’s vanishingly low 0.00006-0.0009% THD (20Hz-20kHz at –10dBFs) increasing to 0.005% through bass and midrange to 0.011% at 20kHz into 25ohm [see Graph 1]. But digital jitter at just 5-8psec [see Graph 2] is as low as we’ve seen from a portable USB DAC – beating the Questyle QP2R [HFN Feb ’18], the Oppo HA-2SE [HFN Dec ’16] and Chord’s own Mojo [HFN Jan ’16]. Noise too is fabulously low and contributes to another standard-setting figure for S/N of 104dB (re. 10mW/25ohm). Relative to its full line-level output, the A-wtd S/N is a massive 116.1dB. PM

Maximum output (re. 0dBFs into 47kohm): 4.58V (line out)
Max. power output (re. 0dBFs into 25ohm): 825mW (headphone out)
Output Impedance (20Hz-20kHz): <100mohm
A-wtd S/N ratio (0dBFs; re. 2V/10mW): 110.1dB / 103.5dB
Distortion (20Hz-20kHz, re. 10mW): 0.0003–0.009%
Freq. resp. (20Hz-20kHz/45kHz/90kHz): +0.0 to –0.dB/–1.5dB/–7.3dB
Digital jitter (into 25ohm / 600ohm): <10psec / <10psec
Power consumption: 2x2600mA/3.7V batteries
Dimensions (WHD) / Weight: 100x130x21mm / 450g
Price: £1800

Chord Electronics Ltd
Supplied by: Chord Electronics Ltd
02890 279839