USB audio, etc.. Re: Re: EgoSys U24

Unorthodox Behaviour wrote:
> 
> Very good card but quite expensive. I just discovered
> OPTOplay in http://www.audiotrak.net/eng/index.html

Some of these USB audio dongles seem to have rather substandard
codecs.  Particularly the Philips uda1331 chipset has rather
high distortion at low scale range.

The Burr Brown/TI PCM2702 looks quite a bit cleaner but
it only renders 16 bits and is just a DAC.  Still, a really
nice package solution.

> If any MAD-user knows an even cheaper 24 bit solution,
> please inform us - it seems that these new USB devices
> are the future of digital audio "cards". I expect that
> costs for these gadgets will reduce dramatically since
> there is no PCI bridge chip involved, no big PCB etc -
> just the DSP chip, audio stream to serial data
> converters and plastic parts.

Maybe at some point, but I haven't found integrated devices
which generate/accept SPDIF data.  Thus I suspect devices
like the OPTOplay are a vendor engineered solution and not
a carbon copy implementation of a chip vendor app note.

With the proliferation of low cost USB devices, it will be
interesting to see whether isochronous USB will become more
of an audio interconnect 'standard' compared to more
specialized interfaces such as SPDIF, etc..  The PCM2702 is
under $5/unit in production quantity.  I can believe a $10/unit
BOM cost is possible.  I have not seen SPDIF solutions even get
close to this.

-john


-- 
John Cooper   [email protected]