Headphones

The 4800mAH Lithium-Polymer battery rolled out in the original iDSD Diablo, combined with an onboard switchmode step-up converter taking the rails to ±15V in 'Nitro' mode, provides both models with extra 'grunt'. This is reflected in the high 2450mW/32ohm rated output of the Diablo 2 via its single-ended 6.35mm socket and realised, in practice, as 9.6V or 150mW into high impedance (600ohm) in-ears, 2490mW/32ohm and a full 2200mW (2.2W) into very low impedance 8ohm headphone types [see Graph, below].

The 300mohm output impedance is also usefully low, ensuring the iDSD Diablo 2/headphone system response is largely unaffected by swings in load impedance – from ±0.02dB 20Hz-20kHz out to +0.5dB/100kHz. Overall gain is –0.1dB (Normal, or unity gain mode), +8.5dB (Turbo) and +17.2dB (Nitro) where distortion is a very low 0.0003-0.0015% (20Hz-20kHz) into 600ohm with a slight rise under load to 0.0005-0.0025% into 32ohm.

Noise is low too with a residual of just –100.5dBV (9.4µV) and a S/N ratio of 95.9dB (Nitro), 100.8dB (Turbo) and 103.1dB (Normal, all re. 1V/32ohm), ensuring the Diablo 2 is both very quiet with high sensitivity ear buds and potently powerful with low impedance cans. The iDSD Diablo 2 is certainly the most capable compact headphone amplifier so far tested in Hi-Fi News. PM