Hi,

I've got a Technics SL-PD688 CD Changer and I would like to extract a
digital audio signal from it to feed into a external DAC. The DAC has
a digital coax input.

Has anyone done this with a CD player that does not come with a
digital out option? Do I just need to find the input to the internal
DAC and tap a signal off from there or is it more difficult than
that?

John.

If you are asking this, I do not think you are up to it. What you
need is the service manual and schematic. From those, you can
determine what signal format is used as input to the OSF/DAC chip(s).
There's only a small possibility that it is in S/PDIF format, so you
will then have to convert it and buffer it for output. If you are
extremely lucky, all you need is a buffer and/or transformer.

Frankly, I do not think the effort is warranted for this one.

Kal


On Tue, 02 Oct 2007 09:25:03 -0700, wrote:

Hi,

I've got a Technics SL-PD688 CD Changer and I would like to extract a
digital audio signal from it to feed into a external DAC. The DAC has
a digital coax input.

Has anyone done this with a CD player that does not come with a
digital out option? Do I just need to find the input to the internal
DAC and tap a signal off from there or is it more difficult than
that?

John.

wrote:
Hi,

I've got a Technics SL-PD688 CD Changer and I would like to extract a
digital audio signal from it to feed into a external DAC. The DAC has
a digital coax input.

Has anyone done this with a CD player that does not come with a
digital out option? Do I just need to find the input to the internal
DAC and tap a signal off from there or is it more difficult than
that?

Easy, and if you've never done anything like this - well why not have a
go! Just watch the power electrics and avoid gazing at the laser...

Google will find you loads of links of people who have done just this ...

-- With a Car radio head unit
http://www.turboegt.com/Audio/Car%20Audio/Digital%20Outs/digital_outpu-f.htm

-- With a portable CD player
http://www.bunniestudios.com/bunnie/proj/cdhack/cdhack.html

- With a NAD HiFI player
http://www.massey.ac.nz/~jcmarsha/hometheatre/522mod.shtml

Open the unit up, identify the main chips and look on the net for
datasheets for these. Unlike schematic diagrams, a lot of datasheets are
available for free download - and will show the first clue that a SP/DIF
interface may be possible.

--
Adrian C