Chord Anni Desktop Amplifier Lab Report

Lab Report

Although Chord offers no specification for its Anni headphone amplifier – aside from a general implication that it leverages off existing, tried-and-tested Chord technologies – the test results are anything but 'ordinary'. Gain is fixed at a modest 5.2dB (x1.8) – a 550mV sensitivity (re. 0dBV) – but this does mean the max. 10.5V single-ended output is only possible from a 5.5V source. Likely? Not really, but as this equates to 184mW/600ohm [black trace, Graph 1 below] your ears will long since have melted. It's also the voltage-clip limit of 3.385W/32ohm [orange trace, Graph 1] – a massive figure and, again, significantly in excess of what's required by even the least sensitive headphones. Using a standard 2V line source, the Anni will deliver 125mW/32ohm which is already the limit of most portable USB headphone amps. Into very low impedance 'phones the Anni is current limited, although 124mW/8ohm [red trace, Graph 1] is generous enough.

Along with the prodigious headroom comes very low noise and an A-wtd S/N ratio of 96dB, improving the Anni's potential for use with very high sensitivity 'phones. The usefully low sub-1ohm source impedance also makes it relatively immune to the peaks and dips of a headphone's load while incurring a minimal 0.1dB signal loss into a standard 32ohm setting. The Anni's native response is tailored, however, with its gentle –0.3dB/20kHz treble roll-off being less significant than the +3.6dB/30Hz low bass boost [black trace, Graph 2]. Distortion, meanwhile, is influenced by loading, particularly at very high frequencies where it lifts from 0.0028%/1kHz and 0.17%/20kHz into 600ohm to 0.003%/1kHz and 0.85%/20kHz into 32ohm at equivalent voltage outputs [blue/red traces, Graph 2]. For a deep dive into the main and highly novel amplifier, see boxout. PM


Power output vs. THD into 600ohm (black), 32ohm (orange) and low 8ohm (red) headphone loads


Distortion versus frequency (0.6V unloaded, blue; 10mW/32ohm, red) and freq. response (black)

Maximum output (<1% THD) 10.5V (47kohm load)
Power output (<1% THD, 600/32/8ohm) 184mW / 3385mW / 124mW
Output Impedance (20Hz-20kHz) 450-600mohm
A-wtd S/N ratio (re. 0dBV) 95.9dB
Distortion (20Hz-20kHz, 0dBV) 0.0018–0.14% (unloaded)
Distortion (20Hz-20kHz, 10mW/32ohm) 0.0009–0.85%
Freq. resp. (20Hz-20kHz/100kHz) +3.6 to –0.28dB/–4.0dB
Power consumption 10W (1W standby)
Dimensions (WHD) / Weight 160x43x97mm / 0.63kg
Price £1195

Chord Electronics Ltd
Supplied by: Chord Electronics Ltd
01622 721444