Philips CD10 portable Lab Report

Lab Report

Sandwiched in between Philips' own very capable CDM-2P disc transport and analogue filter/output stage is the very same time-shared 16-bit DAC we saw in Sony's D-50 [HFN Jan '13]. As a result, while the two portable players share common digital features, the differences observed in the CD10 (launched about a year later) derive almost exclusively from its AC-DC power pack and RC analogue filter (the D-50 employed a more sophisticated, steep roll-off LCR filter). The impulse response [inset, Graph 2] necessarily avoids the pre-ringing associated with standard FIR digital filters – the 0.0113msec offset between left (black) and right (red) a function of the sequential left sample-by-right sample conversion. However, the challenge of tolerancing the RC components is revealed in the (correct) and 'peakier' +1.5dB/14.5kHz response and increased post-ringing seen in the right channel and further reflected in its superior 34dB stopband rejection (falling to just 9dB in the left). Source impedance, meanwhile, rises at low frequency but the 1kohm seen here [green trace, Graph 2] will have less impact on bass performance than the 2kohm of Sony's D-50.

Like Sony, Philips achieved a sub-16-bit A-wtd S/N ratio of 89dB in the CD10 while low-level detail is boosted in similar fashion, so signals at –90dBFs are up by +4.9dB. Peak level THD is moderate, reaching 0.003% at 1kHz and 0.006% at 20kHz before dropping away to a minimum of 0.0016% at 1kHz/–5dBFs [see Graph 1]. The player's jitter performance is also slightly high at 750psec, and data-induced in nature. Finally, the headphone output delivers a full 12mW/600ohm but has insufficient drive to maintain more than 8mW into a standard 32ohm load. PM


Distortion versus 16-bit CD digital signal level over a 120dB range (black, 1kHz; blue, 20kHz)


Freq. and time domain responses (left, black; right, red) and output impedance (green). No digital filter, so no pre-ringing on the impulse response

Maximum output level / Impedance 1.73Vrms / 418-1046ohm
A-wtd S/N ratio 88.9dB
Distortion (1kHz, 0dBFs/–30dBFs) 0.0032% / 0.029%
Distortion & Noise (20kHz, 0dBFs/–30dBFs) 0.0062% / 0.0019%
Frequency response (20Hz-20kHz) +1.10 to –2.75 dB
Digital jitter 750psec
Resolution @ –90dB/–100dB +4.9dB / +5.9dB
Power consumption 5W
Dimensions (WHD, inc. battery) / Weight 125x45x210mm / 1.2kg