Disc Players

ATC has extracted an exceptional performance from its choice of AKM’s 768kHz/32-bit AK4490 ‘Premium’ DAC although the player’s massive 14.5V (balanced) output with CD/digital inputs is still rather higher than typical. The maximum achievable output is 18.4V (via the analogue input) and, with its low 9.85ohm source impedance, the CDA2 Mk2 will surely drive the most adventurous interconnect/power amp combinations! The response via digital sources, and its favourable time domain behaviour, is governed by ATC’s choice of the ‘Short Delay/Sharp roll-off’ digital filter – one of five algorithms offered by the AK4490 DAC that we explored in depth in our review of the TEAC UD-503 DAC/headphone amp [HFN Apr ’16].

This minimum phase filter offers a 100dB suppression of stopband images with CD and a response that rolls-away very gently to –0.3dB/13kHz and –0.6dB/20kHz. With 48kHz, 96kHz and 192kHz digital inputs the response is –0.5dB/20kHz, –1.15dB/45kHz, and –1dB/48kHz to –17.6dB/90kHz respectively, although the inherent (analogue) response of the preamplifier is –1dB/4Hz to –0.04dB/20kHz and –0.7dB/100kHz.

The A-wtd S/N ratio is 110.7dB (digital, re. 0dBFs) and 101.7dB (analogue, re. 0dBV) while ‘digital’ distortion is as low as 0.0001%/1kHz and 0.0009%/20kHz at –10dBFs [see Graph 1]. Distortion via USB and S/PDIF inputs is 0.0006-0.004% from 20Hz-20kHz at 0dBFs (measured at 4V balanced output) while the inherent THD of the preamp stage is 0.0001-0.001% over the same span. Digital jitter is well managed although not entirely eliminated at 55psec (48kHz/24-bit) and 35psec (96kHz/24-bit) [see Graph 2]. PM

Maximum output level / Impedance: 18.4Vrms / 9.85ohm (XLR)
A-wtd S/N ratio (LPCM / CD / Preamp): 110.7dB / 110.7dB / 101.7dB
Distortion (1kHz, 0dBFs/–30dBFs): 0.00064% / 0.00035%
Distortion & Noise (20kHz, 0dBFs/–30dBFs): 0.0043% / 0.00075%
Freq. resp. (20Hz-20kHz/45kHz/90kHz): +0.0 to –0.5dB/–1.2dB/–17dB
Freq. resp. (Preamp, 20Hz-20kHz/100kHz): +0.0dB to –0.05dB / –0.7dB
Digital jitter (48kHz/96kHz / CD): 55psec / 35psec / 145psec
Power consumption: 10W (9W standby)
Dimensions (WHD) / Weight: 445x90x330mm / 7kg
Price: £2950