BOUNTY: Optical Mods

[Shou]

As a means to encourage the discovery/publication of certain mods, I am willing to put money where my mouth is and offer a modern game (Wii/PS2/PS3/360) of your choice + cost for parts if you can provide me with an optical mod and working specs for one of the following consoles:

NO A->D CONVERSIONS WILL BE ACCEPTED!

3DO FZ-1
AV Famicom
Mark III
Mega Drive 1 + Mega CD + 32X (needs to all work but doesn't seem possible)
Neo Geo AES (heard that only A>D is possible but not the real thing)
Neo Geo CDZ
Nintendo 64
PC Engine (more specifically Super Grafx and Super CD-ROM)
Wii

[NFG]

Since most of these systems output fully-formed analogue audio from chips, there's nowhere on the board to tap a digital signal.  Short of replacing these chips with custom units, there's no way to do what you ask. 

[Shou]

Since most of these systems output fully-formed analogue audio from chips, there's nowhere on the board to tap a digital signal.  Short of replacing these chips with custom units, there's no way to do what you ask. 

Can you specifically say which ones? I know for the AES and MD1 that's how it is but I am hoping one of the various models is different.

[NFG]

The PC Engine sound generator's part of the CPU, there's no sound chip for the N64, so it's internal somewhere too.  The Famicoms have internal sound too. 

[l_oliveira]

It might be possible to build a digital converter board for the YM2610 chip (Neo Geo AES and MVS) with a CPLD. It does output serial PCM but in a Yamaha proprietary (and usually chip specific) format. That digital stream goes to the small 16 pin Yamaha chip that is usually close to the A/V portion of the Neo (YM3016)

The Neo Geo CD outputs I2S PCM on both it's custom YM2610 variation of audio chip and the CD-Rom drive. The only issue would be having to mix them before sending to the toshlink/spdif encoder. The NGCD has two D/A chips and the mixing is analogic. A digital mixer inside the custom YM2610 chip would be much cheaper (all consoles since the Saturn and Playstation do it)


Nintendo 64 has a I2S stream coming out of the RCP chip, just like the SNES had. This one is probably feasible.
3DO FZ-1 has a Asahi D/A chip, again I2S. 100% possible. (I don't have one to try it though)

[panzeroceania]

what about the Mark III and it's FM chip?