I have previously owned several Lector CDP 7TL CD players, including a MkII that had the BB-PCM63 20-bit DAC chipset, and the otherwise identical MkIII that used the newer BB-PCM1704 24-bit chipset. The PCM1704 chip was said to be just a little more accurate with better resolution but some (including me) found the PCM63 chip to be more musical with a more engaging tone. As I recall, there were (at least) three types of PCM63 chips, with the PCM63P-K providing the highest dynamic range and lowest harmonic distortion. Below is a description of the chip:
DESCRIPTION
The PCM63P is a precision 20-bit digital-to-analog converter with ultra-low distortion (–96dB max with a full scale output; PCM63P-K). Incorporated into thePCM63P is a unique Colinear dual-DAC per channel architecture that eliminates unwanted glitches and other nonlinearities around bipolar zero. The PCM63P also features a very low noise (116dB max SNR;A-weighted method) and fast settling current output(200ns typ, 2mA step) which is capable of 16-times oversampling rates. Applications include very low distortion frequency synthesis and high-end consumer and professional digital audio applications.