Headphones

We've tested numerous iterations of iFi Audio's portable headphone amps, including the nano iDSD [HFN Dec '14], the 'Black Label' variant [HFN Apr '18], the 'original' xCAN [HFN Feb '19] and EISA Award-winning xDSD [HFN Jul '18], and ZEN DAC [HFN Jul '20] – all, except the xCAN, incorporating DAC and headphone amp functions. The new ZEN-shaped CAN, like the xCAN, is a purely 'analogue' headphone preamp but, by some margin, is its most capable to date, exceeding the output of all its predecessors by delivering up to 1580mW (1.6W)/32ohm and a not insubstantial 655mW/8ohm. However, power output is influenced by the CAN's gain setting, falling to 425mW/32ohm in its 0dB mode [see Graph 1, below].

Other factors, including distortion and the A-wtd S/N are also skewed by your choice of gain setting, not least because the ZEN CAN's auto level-matching op-amp input sees a marked increase in THD with inputs beyond 550mV (from 0.001% at 400mV in, to 0.02% at 900mV in). The input clips at 3.7V. With the gain set to +12dB or +18dB, THD falls to as low as 0.00025-0.0017% (0dBV/600ohm), increasing under load (10mW/32ohm) to 0.0013-0.0019% [see Graph 2, below]. In practice the 0dB mode is ideal for high sensitivity earbuds as it offers the widest 100.5dB A-wtd S/N ratio (re. 0dBV) and lowest –100dBV residual noise. The +18dB gain setting offers 93.9dB and –97dBV, respectively.

Output impedance is impressively low at 510-800mohm in the 0dB setting, reducing still further to 415-605mohm in the +18dB mode, while the response is flat to within ±0.1dB from 1Hz-60kHz. So, in practice, the ZEN CAN will cause very little modification to the overall system response regardless of the impedance of the attached headphones. PM