michael123;571627 Wrote:
> Phil,
> I think you ignored time scale, what about phase response?
Timescale is fixed by the DAC clock, which is supposed to be a constant
for the duration of a replay event.
Almost no DAC's take their clock directly from the s/pdif stream any
more - they almost all lock on to determine the Fs and then read data
out of a word buffer using a local high-precision clock, set to match
the rate of the s/pdif clock. They are thus immune to changes (jitter)
in the s/pdif embedded clock as they rely on their internal clock to
drive the data into the DAC at a constant rate. This is why improving
the DAC clock and its PSU CAN have a dramatic effect on reproduction
quality, regarless of what is happening in the transport. The Transport
just has to get the correct bits to the DAC... without introducing
RF/noise into the s/pdif line that can worm its way through to the DAC
and upset the DAC clock and other post-DAC circuitry.
{dons flame-proof suit and waits for fireballs from hell...)
All we have is a bunch of samples (digital words) that represent
instantaneous amplitude values, replayed at a fixed (ignoring jitter)
clock rate, creating amplitude changes over time = frequencies.
Variations in clock rate will alter the frequencies.
Or to put it another way, phase response accuracy is a function of
frequency response accuracy - you can't change them independantly, even
by accident.
--
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.
------------------------------------------------------------------------
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View this thread: http://forums.slimdevices.com/showthread.php?t=71321
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