DIN8 RGB + Stereo

[Sumez]

The PC Engine mod page suggests using a DIN8 plug for the RGB mod, since it can easily replace the existing DIN5.
That makes sense, so I'll obviously use that. It also says that I need to drop composite in order to get stereo sound.
How does that make sense? The way I see it, I need just eight pins for an RG signal with stereo:

Lchannel
Rchannel
Ground
+5V
R
G
B
Composite

Since sync is already in the composite signal. To my knowledge, scart cables don't even use a clean sync signal. -> http://utopia.knoware.nl/users/eprebel/Sou...ring/SCART.html

[NFG]

You should read all the words, not just some of them:  

"The disadvantage though is that you can't have both composite video and composite sync if you plan to run stereo sound, +5v, GND and RGB as well. You run out of pins, and a switch would be required. "  Obviously if you don't want composite sync this doesn't apply to you.  =P

[Sumez]

Oh right, I missed that. I was confused because the suggested 9 pin plug doesn't have composite sync either.

[Sumez]

This is somewhat off-topic, but related to the same mod.
I can't decide how to map the DIN8. I have three choises, basically:

1. Use the same pinout as the PCE DIN5 plug, and using the three extra pins for RGB, which will make it more "PCE compatible".

2. Base it on the Neo Geo AES pinout, but replace the sync with Rchannel for stereo sound. The cable will then technically work on AES, Master System and MegaDrive, except for the sound, unless I decide to make some kind of stereo mod on those.

3. Use the exact same pinout as AES, with mono sound, and tap the stereo sound from the CD-ROM Interface Unit, like the Neo Geo or SMD headphones trick, which will make it fully compatible with the other machines, but is a bit messy and requires using the interface unit for stereo sound, and more hard work making the cable.

I know it's a matter of taste, but any suggestion as to what to do? It's probably gonna be either 2 or 3, but I can't really decide what I want. :|

[Sumez]

Oooh, one more thing. If I don't use the composite sync signal, I assume I don't have to amplify the composite signal, since I'm taspping it from the existing video output?

[NFG]

Correct, the 9pin doesn't have enough pins for composite sync + video, that's why I used a switch.

Yeah, it's completely a matter of taste and preference.  If you're able to do these sorts of mods there's a better than even chance you can make your own cables as well so there's only a small time-saving advantage to preserving any kind of connector compatibility.

regarding your last question, you're right: using the signal that you've been using already (composite video) does not require an amp.

[Shimarisu]

If you're doing a mod for a UK SCART TV there is no need whatsoever for more than 8 pins, so if that's what you want then go for it. I do precisely these types of mod myself. Although I can never seem to get DIN sockets with the ground pins at the front in the same place as the ones on the original socket. So I have to glue it in to make it stable, as below:

Something else that's neat is to remove the RF modulator from a white PCE and JB Weld (that's really awesome epoxy that holds as well as surface mounted components) an 8 pin mini din into the casing where the socket for the RF went. Of course you can do this precise trick with a 9 pin DIN too, so if you want extra pins on the mod, buy a chassis mount DIN socket and glue this inside the casing. On white PCES and Core Grafx etc, you have to cut away a tiny bit of casing inside the unit to do this, but it looks good and you can't see it from the outside.

[Sumez]

Thanks for the warning.

Seems I have to look for a din socket.