Meridian MCD CD player Lab Report

Lab Report

Comparisons with Philips' earliest 4x oversampled 14-bit player, the CD100 [HFN Oct '11] is clearly of most interest as Meridian used the CD101 as a 'donor' chassis for its proprietary upgrades while also coating the bodywork in a Nextel finish. At the time, improvements to the PSU and tracking/focus performance of the swing-arm mechanism were cited – the transport being able to read the CD-R discs we use today for lab testing (recordable CD was introduced in domestic guise in 1992). The MCD necessarily retains Philips' first-generation 14-bit/4x oversampled DAC, the TDA1540, and so its 'digital' performance – the ~430psec of (complex) jitter, the excellent +0.5dB linearity error at –100dBFs, the idle pattern tone at 3.75kHz (–118dB re. 0dBFs) and the 52dB stopband rejection is unchanged. As are, I might add, the ±0.25dB in-band ripples caused by the limited number of taps and truncation of the impulse in its first-generation FIR digital filter [see Graph 2, below].

Distortion, too, at ~0.0025% (0dBFs, 20Hz-20kHz) is linked to the DAC, including the 'steps' at –25dBFs and –80dBFs [see Graph 1]. There are differences between the CD100 and MCD, and most are related to Meridian's aftermarket output stage with its 4th-order analogue filter. So the very top-end of the frequency response drops to –1.3dB/20kHz instead of –0.6dB while the improved buffer offers a lower, and more cable-agnostic, 13-26ohm output impedance instead of Philips' 48-250ohm. The improved PSU and analogue PCB layout also reduces low frequency crosstalk to below –100dB while the A-wtd S/N ratio is improved from 104dB to 107.5dB here. The maximum 2.1V output level is not significantly different but the polarity of the output is inverted [again, see Graph 2]. PM

1121vint.lab1

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

1121vint.lab2

Frequency (magnitude) and impulse (time)responses. Note ±0.25dB response ripple

Maximum output level / Impedance 2.1Vrms / 12.6-28ohm
A-wtd S/N ratio 107.5dB
Distortion (1kHz, 0dBFs/–30dBFs) 0.0027% / 0.015%
Distortion & Noise (20kHz, 0dBFs/–30dBFs) 0.0023% / 0.0078%
Frequency response (20Hz-20kHz) +0.07 to –1.3dB
Digital jitter 427psec
Resolution @ –90dB/–100dB +0.4dB / +0.5dB
Power consumption 16-22W
Dimensions (WHD) / Weight 320x73x267mm / 5kg
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