I showed you my Neo-geo MVS 1 slot motherboard in my last post which is pretty awesome! And one of the awesome things about it is the MVS system produces stereo sound from the motherboard. Normal JAMMA games are mono only, but Neo-Geo broke the mould a bit by adding in a second speaker into their MVS cabinets and gave all us geeks stereo. So if you have the corresponding connection and cable you can have 2 speakers wired up and get some left to right speaker action going on!
My Supergun is wired for Jamma Mono as it's wired to the JAMMA standard except for the controller ports, so an option to have stereo sound from the MVS motherboard is pretty cool.
There's a problem though, the stereo connector on the motherboard isn't just a coax jack or anything as simple as that. Its just 4 pins, and that's it. What do you do with that if you don't have an MVS arcade cabinet that has all the required wiring inside it to set up all the stereo etc?? You make a connector that's what you do! haha
Well I couldn't think of how wire up a phono jack to it off the top of my head but one saturday morning last month I woke up early with a brain fart! I must have been thinking about the 4 pins in my sub-concious because I woke up with the idea going round my head that a floppy disk power connector from a PC PSU might fit that kind of 4 pin arrangement!
I jumped out of bed and went to our hobby room and stared bleary eye'd scrutinizing the 2 FDD connectors on my spare PC PSU. I got the MVS motherboard out of its box and offered up the connector...... it didn't fit! Dang it! It was really really close but the pins wouldn't go into the connector. Trying not to be disheartened I tried the other connector on the PSU just to eliminate all the options and guess what? That one fits!!! :D
After quickly getting dressed and brushing my teeth I was off to the kitchen to where my soldering stuff is with my MVS manual in hand.
Looking at the MVS boards wiring diagram it shows the stereo jack being wired : pin 1 +, pin 2 -, pin 3 -, pin 4 +. So pins 1 and 2 are the left speaker and pins 3 and 4 are the right speaker. One of the nice coincidences with the wire colours on the FDD connector is the 2 middle wires are black which is a ground colour for me. So it will be easy to make sure pins 2 and 3 are going to be ground or speaker negative.
Here is a photo of my parts and the schematic in the background.
The red and white stereo ends are from the donor coax to phono cable I had lying around. I snipped them off and the idea is to solder the phono connector to the FDD cable. This will then be the stereo connector for my MVS.
I seperated the 4 wires on the phono cable and made them right and left and trimmed the insulation off the wires and tinned them. I put some heatshrink on the wires to insulate them once soldered. A quick touch with the soldering iron and all 4 wires are soldered together.
I quickly wrapped some electrical tape around the solder joints and went upstairs to check it all worked and ding ding! Stereo sound coming out of the MVS! YES!!
I unpeeled the electrical tape, slid the heatshrink over the solder joints and gave them some heat from the hair dryer and bingo bango, I had a completed stereo connector and can now enjoy my Neo-Geo games in glorious steri-eri-ooo.
Here is the new connector and speakers hooked up.
And here is the finished cable on its own.
It's a very easy cable to make and I recommend it if you have an MVS motherboard that has the stereo connection option on there. Its just a matter of getting hold of a donor phono jack and a spare floppy disk power cable from an old PC PSU and your sorted. :-)
Catch you later yo for the next thrilling installment in the 'making your own arcade cables'!! :-P