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View Full Version : Modifying squeezebox clock



Christian Pernegger
2005-02-28, 15:25
>You're missing the point completely. It's not as simple as "the bitstream
>is transmitted intect or it is not". At the implementation level, this
>"bitstream" is actually a sequence of precisely-timed voltage transitions.
>This stream is decoded by the DAC to produce the analogue waveform. If the
>timing of those transitions is slightly out then the analogue waveform is
>distorted.

Only if you don't buffer. :) For any sane transmission protocol it is just
as simple as bit-identical or not. How well this data is transformed into in
anologue waveform and what distortions the analog signal might suffter on
its way to the speakers is another chapter.

>>Everything else can be fixed by reclocking and hinges on the quality of
>>the reclocking.

>Ah, but who said anything about re-clocking?

I did. IIRC in every post from the very start. You probably just read my,
admittedly stupid, bitrate --> jitter conclusion and discarded the rest of
my posts.

>Not all DACs do re-clocking. Those that do it well are not cheap.

I remember having written something along the lines of "why don't all DACs
do this, when RAM is so cheap?"

>http://www.av123.com/products_product.php?section=processors&product=1.1

$1000 for a DAC with a bit of RAM? I guess they can get away with it...
makes me wonder how something like the M-Audio 66 stacks up, jitter-wise :)

>You seem to be saying that you agree that jitter exists as a problem

Sure

>and are presenting several mechanisms to reduce it.

Spot on again. I think this whole thread was about reduction of jitter,
seeing as it started with the suggestion of replacing the clock chip.
Personally I find buying a DAC that properly buffers and reclocks preferable
to a clock chip upgrade.

>I never said that jitter is *always* a problem, merely that in low-budget
>equipment it often is.
>Consumer audio equipment is designed to a budget

K, maybe I'm really confused... I think we were talking about combining a
Squeezebox (high priced consumer item) an external DAC (hardly a consumer
item) and perhaps other upgrades (clock) to get something audiophile out of
the Squeezebox.

A consumer just lives with the analogue out. It's not _that_ bad really.

For the audiophile enthusiast, what's $1000 for a DAC. If it's done right
it's the only thing you'll need to get great sound quality out of almost any
kind of digital input.

Chris