Crown CD-110 CD Player Lab Report

Lab Report

Of the two 3.5mm outputs offered, the line out is fixed at 1.5V from a high 960ohm source impedance (increasing to 1.9kohm/20Hz) while the variable headphone output reaches a full 4.2V before clipping from a flat and usefully low 40ohm. Otherwise, the core of the CD-110's performance is largely determined by Crown's choice – and implementation – of Yamaha's 16-bit YM3015 DAC which incurs a very high ~4750psec of jitter withsidebands radiating out at multiples of ±14Hz, ±20Hz and ±30Hz. These frequencies will be linked to specific processes and/or IM distortions within the CD-110. The A-wtd S/N ratio is a sub-16-bit 92dB although low-level linearity is good to ±2dB at –96dBFs/1kHz, falling to –2dB at –80dBFs/20kHz.

A sequential sample-and-hold DAC would ordinarily result in a 0.0113msec offset between left (black) and right (red) channels, but this is halved here (and the interchannel phase lag reduced from 90° to 45o) thanks to 2x oversampling. This is a primitive linear phase digital filter, invoking both pre- and post-event ringing [see impulse, Graph 2], that delivers a poor 17dB stopband rejection (24.1kHz re. 20kHz). The filter also defines the player's frequency response [also Graph 2] with its +0.6dB/13kHz treble peak and steep –1.5dB/20kHz roll-off. The latter is important, for while stopband rejection is weak, the impact of the analogue filter bites more effectively >30kHz, helping to suppress HF distortion harmonics. This is the reason why THD at 20kHz [blue trace, Graph 1] is up to 10dB lower than through the midrange [0.005% vs. 0.02%, black trace] between –10dBFs and –35dBFs, and why treble harmonics are principally 2nd harmonic and midrange harmonics more extended. PM

1023vint.l1

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

1023vint.l2

Frequency (0.2dB/div) and time domain responses (left, black; right, red). Output is phase-inverted and note 2x linear phase filter ringing

Maximum output level / Impedance 1.52Vrms / 955-1880ohm
A-wtd S/N ratio 91.5dB
Distortion (1kHz, 0dBFs/–30dBFs) 0.033% / 0.019%
Distortion & Noise (20kHz, 0dBFs/–30dBFs) 0.14% / 0.0045%
Frequency response (20Hz-20kHz) –1.5 to +0.65dB
Digital jitter 4750psec
Resolution @ –90dB/–100dB +1.7dB / +3.5dB
Power consumption 3W
Dimensions (WHD) / Weight 156x51x203mm / 1kg
ARTICLE CONTENTS

X