Archived from groups: alt.comp.periphs.mainboard.asus (
More info?)
"Paul" <nospam@needed.com> wrote in message
news:nospam-1912041007000001@192.168.1.177...
> In article <lm7xd.7248$iE.1420@fe40.usenetserver.com>, "David Swager"
> <dwswagerREMOVE@knology.net> wrote:
>
>
> It is possible there are three ways to get audio from a CD:
>
> 1) Connect analog four pin cable from drive to CD connector.
> (See lower left corner of motherboard for CD connector).
> 2) Don't bother with the old four pin cable. Enable DAE (digital
> audio extraction), which allows the CPU to pull blocks of
> digital data across the IDE cable, for playback through the
> sound subsystem.
> 3) Try the two pin digital output on the drive. It is some kind
> of PCM (pulse code modulation), but I find conflicting comments
> in Google on the topic. Some claim it is SPDIF, and at least
> one high end audio product hooks onto that output, and uses
> some high quality DACs to make audio from the stream.
>
> Comments in Google claim some drives have the 2 pins, but there
> are no electronics in the drive, to put signals on the pins.
>
> One person claims he connected the two pins to his SPDIF input
> and it worked. (Who knows, maybe he was using DAE and didn't
> know it.)
>
> In any case, be aware that the 2x3 SPDIF header on the Asus
> motherboard does not use standard SPDIF levels. SPDIF is usually
> transformer isolated and low amplitude, like <1 volt or so.
> The header on the Asus motherboard is intended for use with an
> Asus bracket first, and the bracket converts what presumably
> are logic level signals down to the low amplitude signal. One
> Asus bracket I looked at, has a resistor divider network on
> SPDIF_out, to convert the signal from the 2x3 header, to the
> proper level. On the input, that bracket had a buffer chip,
> to convert the <1 volt signal into a logic level.
>
> Note that, there are also some older versions of the Asus bracket
> that contained no buffer chip on SPDIF_in. It looks like someone
> at Asus thought that the AC97 chip would amplify the signal level
> or something, and a number of users were disappointed to find that
> their SPDIF_in (on the ALC650) wouldn't work, even though the
> chip rev number was sufficient for the purpose.
>
> This is the bracket I would try to find, if I were to try your
> experiment. Basically, you would run a coax cable from the two
> pins on the drive, to the SPDIF_in on this bracket. The 14 pin
> chip on the bracket converts the SPDIF_in signal to a
> level suitable for the 2x3 header on the motherboard.
>
> Since I never received any feedback from previous posters, I
> don't know whether anyone could find this, or got it to work.
>
>
http://usa.asus.com/products/mb/images/accessories/SPDIF-IN-OUT-COA-Module.jpg
>
> And, this is the module I wouldn't want, as it has no buffer
> chip, and the design was presumably based on a wrong assumption
> about how the motherboard works:
>
>
http://www.asus.com.tw/mb/mbimages/accessories/SPDIF_COA.gif
>
> AFAIK, this is the SPDIF spec for a real SPDIF device. The
> Asus only meets this on the RCA jacks on the SPDIF bracket
> (or any built-in jacks on the back of the motherboard).
> You'll need an RCA plug, length of 75 ohm cable, plus a
> couple of pins and contacts for the CDROM end of things.
>
> Cable: 75ohm +/-5% (l<10m) or 75ohm +/-35% (l>10m)
> * Line driver:
> * Zout: 75ohm +/-20% (100kHz .. 6Mhz)
> * Vout: 0.4Vpp .. 0.6Vpp, <0.05Vdc (75ohm terminated)
> * Line receiver:
> * Zin: 75ohm +/-5%
> * Vin: 0.2Vpp .. 0.6Vpp
>
> If you go to this site
http://frontx.com/order_c.html you can
> find a 1x2 plug and some pins:
>
>
http://frontx.com/cpx075_8.html "1x2 header plug"
>
http://frontx.com/cpx076.html "female pins"
>
> If the pins on the drive are on 0.1" centers, the Frontx parts
> might work. But, there is a slightly smaller kind of connector
> sometimes used, and I don't know where to find a solution
> for that. I think the male pins in that case are smaller as
> well, and the frontx pins would be a sloppy fit.
>
> For all the hassle, I think investigating DAE is infinitely
> simpler.
>
> If you try this the hard way, please post back with your
> experiences, as there are still a few people who want a
> way to do SPDIF_in.
>
> Paul
Thanks for the responses. I ended up letting the DVD-ROM and DVD Writer use
the IDE Channel via the DAE options in the properties settings. This works
fine.
Connected a Leadtek PVR2000 TV/MPEG card to the only analog in port on the
motherboard. Funny thing is that the Sound from this card is fine in
Windows XP Media Center application, but I don't get any sound from the
Leadtek PVR application.
Thanks again!
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