For Marantz cd 57, 60, 63, 67 and SE versions of each. They also have a complete DIY DAC project for die-hard tweaker, plus a cd-clock upgrades.
http://www.tnt-audio.com/clinica/tweaks.html
Here's another using the Phillips 1252-10 cd engine
http://www.geocities.com/agalavotti/cdpro.htm
Here's another for a Technics SL-PG 580
http://www-user.uni-bremen.de/~carnivor/cdp/cdp.html
This one has a bunch of DIY DAC's
http://www.diyaudio.de/
A 24/96 DAC
http://www.geocities.com/CapeCanaveral/Galaxy/6623/24bitdac.html
This DAC has a tubed out put & sells PCB's
http://www.megabaud.fi/~jtolonen/projects/projects.html
Tubed DAC w/ $125 PCB from SDS Labs
http://www.clarkson.edu/~stokessd/dac.html
Hope this helps prove that it's possible.
http://www.tnt-audio.com/clinica/tweaks.html
Here's another using the Phillips 1252-10 cd engine
http://www.geocities.com/agalavotti/cdpro.htm
Here's another for a Technics SL-PG 580
http://www-user.uni-bremen.de/~carnivor/cdp/cdp.html
This one has a bunch of DIY DAC's
http://www.diyaudio.de/
A 24/96 DAC
http://www.geocities.com/CapeCanaveral/Galaxy/6623/24bitdac.html
This DAC has a tubed out put & sells PCB's
http://www.megabaud.fi/~jtolonen/projects/projects.html
Tubed DAC w/ $125 PCB from SDS Labs
http://www.clarkson.edu/~stokessd/dac.html
Hope this helps prove that it's possible.