Vintage

In common with its CDP-552ESD model, and in contrast with the preceeding CDP-502ES which used Sony's CX20152 DAC, the mkII CDP-502ES from 1986 used neither Philips nor Sony DACs but a pair of monolithic PCM53JP-V converters from Burr-Brown. These 16-bit DACs were deployed with Sony's CX23034 2x oversampling filter to form what it described as its 'Unilinear Converter System'. The impulse response [inset, Graph 2] shows the pre- and post-ringing associated with this linear-phase 2x digital filter while the frequency response with its mild +0.06dB bass shelf and ±0.02dB HF ripple is still significantly flatter than that achieved by Sony's earlier-generation players that used the PCM53P DAC [HFN Feb '21]. Combined with Sony's 'GIC' analogue filter, the stopband rejection is a full 87dB while distortion at the peak (0dBFs) output of 2V is very low (especially for the era) at ~0.0004% right across the 20Hz-20kHz audio range. There are disc players and outboard DACs that don't achieve that kind of figure at 20kHz some 35 years later!

The low-level linearity and trend of distortion vs. digital level offered by the PCM53JP DAC is also markedly improved over the PCM56P, although the fact that THD is generally lower at 20kHz than 1kHz (0.009% vs. 0.013% at –30dBFs) is as much a function of the analogue filtering pinching off digital harmonics above 25kHz or so [see Graph 1, below]. The player's linearity is good to ±0.5dB over the top 100dB of its dynamic range, and with a 101dB A-wtd S/N ratio this corresponds to a resolution of some 16.5 bits. Jitter, meanwhile, is moderate at 430psec and while free of PSU sidebands is almost entirely data-induced in nature. Subjectively this is not especially ideal but, back in 1986, it's not something we (or Sony) could measure. PM