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Subject: Re: Cheap/good digital-audio Boston Acoustics BA735

Re: Cheap/good digital-audio Boston Acoustics BA735

From: David McIntyre <>
Date: Fri, 5 Sep 2003 15:56:03 -0700

The MAS data sheets have an errata that covers unstable S/PDIF clock signals.
They recommend using parity and checking after every frame. Talk about a pain
in the butt! I wonder if that's handled in the Archos code.

On Fri, Sep 05, 2003 at 05:28:06PM -0500, LoveLearn wrote:
> Sharing research results:
> 1984 standard S/PDIF is unbalanced .5 volt originally designed for
> lengths up to 1 meter.
> For long feeds, lots of vendors sell S/PDIF converters to produce 1985
> AES/EBU (Audio Engineering Society/European Broadcast Union), a balanced
> 5 volt similar standard reportedly useful to 100 or 200 meters,
> depending on which description you read.
> >From
> "You can run S/PDIF up to a metre or two without any problems at all,
> almost regardless of the type of cable, and if you use decent 75(omega)
> coaxial cable (proper 'digital' cable or standard video coax) you can
> run an S/PDIF signal several metres.
> However, if you are intending to run an S/PDIF signal to a D-A converter
> I would say keep the cable as short as you possibly can, because
> cable-induced jitter will affect the decoder's clock in a detrimental
> way. The D-A relies directly on the embedded clock signal and cable
> jitter will mess this up. The longer the cable, the more capacitive it
> is and the greater the jitter will become. Very few budget D-A
> converters have decent jitter-rejection properties able to cope with the
> effects of long cables. Jitter can be heard as a vagueness in the stereo
> imaging and very flat, two dimensional sound stages on well-recorded
> acoustic material."
> Satisfied S/PDIF cable user reports seem to stop at about 12 feet. So
> much for the cheap long runs pipe dream. I still don't know if a single
> S/PDIF output can simultaneously drive two inputs using a simple in-line
> splitter.
> Here's an instructive S/PDIF site:
> Andrew's S/PDIF Stuff

David McIntyre
PGP Key fingerprint = CAB5 A73A 43FA 19E3 449D  20B8 25D7 FA84 8847 D6A7 for geek code, pgp key, etc. 
Received on 2003-09-06

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