Sharp DX-411H CD player Lab Report

Lab Report

Second generation it may be, but this early 16-bit CD player still faced strong competition from Philips' first-generation CD100 [HFN Oct '11], CD303 [HFN Nov '13] and CD104 [HFN Apr '14]. Their 14-bit/4x technology offered the potential of lower distortion, a wider S/N and superior low-level resolution (+1.5dB over a 90-100dB dynamic range) – and all without the phase shift incurred by time-shared DAC. In practice, Sharp's own 16-bit DAC used here delivers better all-round results than we saw with B&O's CD50 [HFN May '15]. Both the Sharp and B&O players are otherwise built around a very similar (Aiwa-sourced) digital platform that includes Yamaha's YM2201F 2x oversampling filter.

The impulse response [inset, Graph 2] shows the pre-ringing associated with this basic FIR 2x oversampled digital filter which offers a limited 22dB stopband rejection while also inverting absolute phase. It does reduce the interchannel phase-shift of a single time-shared DAC and while the frequency response [Graph 1] shows the same +0.25dB/20Hz bass lift we saw in the CD50, the DX-411H's custom analogue stage delivers a gently declining mid/treble trend that rolls away to –0.4dB/10kHz and –2.8dB/20kHz. In-band response ripples are also much reduced over those seen in earlier-generation players.

The DX-411H's 2.03V output level is standard and even if the ~3kohm impedance is really too high at least the 101dB A-wtd S/N ratio is acceptable, as is the –1.9dB error in resolution at –90dBFs and fairly consistent ~0.0025% THD from 20Hz-20kHz. At lower digital levels, the effect of Sharp's analogue filter reduces distortion harmonics at high frequencies [blue trace, Graph 2]. Jitter is a little high at ~1100psec – mainly data-induced and with ±100Hz switching noise from the PSU rectifier. PM


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


Freq. resp. [top] and impulse response [below]. Pre/post-echoes reveal early 2x FIR digital filter

Maximum output level / Impedance 2.03Vrms / 3.13-2.48kohm
A-wtd S/N ratio 101.0dB
Distortion (1kHz, 0dBFs/–30dBFs) 0.0022% / 0.0063%
Distortion & Noise (20kHz, 0dBFs/–30dBFs) 0.0029% / 0.0015%
Frequency response (20Hz-20kHz) +0.25 to –2.8dB
Digital jitter 1100psec
Resolution @ –90dB/–100dB –1.9dB / +3.5dB
Power consumption 10W
Dimensions (WHD) / Weight 364x78x305mm / 4kg