Outboard DACs

When we tested the inaugural xDSD [HFN Jul '18] its performance marked a clear uplift on iFi Audio's earlier portable DAC/headphone amps, including the nano iDSD [HFN Dec '14] and 'Black Label' variant [HFN Apr '18]. It was also the brand's most powerful battery-powered amp – rated at 270mW/50ohm and 500mW/16ohm, it delivered a comparable 330mW/25ohm on test with 3.35V or 18.7mW/600ohm for high impedance headphones. Four years later the xDSD Gryphon, the xDSD's 1750mAH Lithium-Polymer battery replaced here with a 3600mAH cell for extra 'grunt' and +90g bodyweight, is rated at 320mW/32ohm. Again, on test, the xDSD Gryphon matches the xDSD's specification into high impedance loads with 3.33V or 18.5mW/600ohm but its extra current capability delivers an uplift into lower, tougher headphone loads at 314mW/32ohm and a full 520mW/8ohm [see Graph].

The 500mohm output impedance is also usefully low, ensuring the xDSD Gryphon/headphone system response is largely unaffected by swings in load impedance – from –0.2dB/20Hz to –0.05dB/20kHz (without bass/presence shaping) out to –0.7dB/100kHz. But, in a further twist, the nested feedback regime adopted in the Gryphon ensures distortion is a fairly constant 0.004-0.006% (20Hz-20kHz) into 600ohm with a slight rise under load to 0.008-0.015% into 32ohm. Noise is low too with a residual of just –101dBV (9µV) and a S/N ratio of 101.5dB (re. 1V/32ohm), ensuring the xDSD Gryphon is both quiet with high sensitivity ear buds and lusty with low impedance cans. PM