Stereoeditor;580201 Wrote: > Just saw this question. If you are talking about the undithered tone at > -90.31dBFS I show in all my DAC measurements, I use this signal, not > because it will be typical of music, but because it is diagnostic for > DAC problems. In 2s-complement PCM encoding as used on CD, the change > in level from digital "0" to +1 LSB actually involves all bits in the > 16-bit word changing value. By contrast, the change from "0" to -1 LSB > involves just the LSB changing value. So you can immediately see from > the symmetry of the waveform, and how well-defined the 3 voltage levels > are, whether or not the DAC is sufficiently monotonic and the analog > noisefloor is sufficiently low to allow those data to be correctly > decoded. > > In other words, it's a thumbnail indicator of DAC quality. > > In general, the test is not as useful in these days of sigma-delta DACs > as it was when all we had were multi-bit DACs. However, you still come > across pathological designs that fail to reproduce this signal properly > - see, for example, fig.8 in the Cary review in the September 2010 issue > of Stereophile. > > John Atkinson > Editor, Stereophile John - thanks - very interesting - please bear in mind I haven't read the article in question so I was basing my remarks on an interpretation of what others had said (!?)... Hopefully I will get to read the article at some point. regards Phil
-- Phil Leigh You want to see the signal path BEFORE it gets onto a CD/vinyl...it ain't what you'd call minimal... Touch(wired/XP) - TACT 2.2X (Linear PSU) + Good Vibrations S/W - MF Triplethreat(Audiocom full mods) - Linn 5103 - Aktiv 5.1 system (6x LK140's, ESPEK/TRIKAN/KATAN/SEIZMIK 10.5), Pekin Tuner, Townsend Supertweeters, Blue Jeans Digital,Kimber Speaker & Chord Interconnect cables Kitchen Boom, Outdoors: SB Radio, Harmony One remote for everything. ------------------------------------------------------------------------ Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=82050 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
