Article Index
Astell&Kern AK120 portable player
Page 2
Sound Quality
Measured Performance
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Rohde & Schwarz UPV

Rohde & Schwarz UPV  – the world's most advanced audo analyser.


Like the AK100 tested in our March13 issue, the headphone output of this player delivers very high output of 1.6V, close to the 2V from a CD player and much higher (+14dB) than the usual 0.3V of a typical portable player.
    The DAC and output amplifier were even quieter than the AK100, noise measuring -115dB with a notched out -60dB tone (24bit), to avoid output muting. This raised EIAJ Dynamic Range to 115dB with 24bit, making the AK120 comparable to the best stand-alone DACs. The headphone output is in effect a high quality analogue line output and can be used as one.
    Frequency response was flat from 4Hz to 73kHz (-1dB) using a 192kHz sample rate signal, as the analysis from our Rohde & Schwarz UPV analyser shows, so here again the headphone output performs as well as a quality DAC, maintaining the full analogue bandwidth of 192k sample rate digital.
    Distortion at -60dB was low with 16bit, measuring 0.18% and very low with 24bit at 0.04%, as our distortion analysis shows. This result and low noise both contributed to the player’s high EIAJ Dynamic Range figures.
    Jitter on the digital output was very low in all areas, uncorrelated jitter hovering at 6pS across the audio band, with little high rate jitter above 20kHz. Signal related jitter (1kHz, -60dB test tone) measured a very low 10pS and low rate clock wander was also low at 45pS. These are excellent figures.
    The AK120 produced exceptional results for a portable player, improving even upon the excellent AK100. It has massive dynamic range, low distortion and negligible jitter and is way ahead of other portables, comparing with the best stand-alone DACs. NK

Frequency response (-1dB)
192k sample rate    4Hz-73kHz

Distortion (16 / 24bit)    %
0dB    0.0008 / 0.0008
-60dB    0.18 / 0.04

Separation (1kHz)                109dB
Noise (IEC A)                       -115dB
Dynamic range (16/24bit)    102dB/115dB
Output                                  1.6V


FREQUENCY RESPONSE    192kHz sample rate


DISTORTION     24bit, 0dB


DISTORTION     24bit, -60dB


EIAJ DYNAMIC RANGE  (–54.7 + -60)






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