Astro City Stereo Wiring
The Sega Astro City line is capable of Stereo sound output, and this page will tell you what you need to know to get your cabinet up and going with Stereo sound, there are a few reasons why you would want to do this, but the most obvious reason is much better sound in stereo supported games. Some games have surround sound and will use balance on the speakers to indicate where certain things are coming from, making them easier to play with stereo sound. If you have a stereo game, wire it stereo, it will make the game much more enjoyable.
Before we begin, we need some things
- A Stereo Amp
- A Stereo Game
- A Wiring loom for your amp, If you have a optional JVS wiring harness, you will have RCA connectors somewhere in your cab, and that works great for Gradius IV and CPS2 games for example
That list assumes that you have a stereo amp in your cabinet already. If not, don't fret, they're pretty cheap on eBay and easy to install.
The first step is to disconnect the Mono harness from the speakers, Sega made a good decision when they designed this, as back when these cabinets were built it was rare to find boards that could handle mono and stereo output at the same time without blowing out their sound chips. To disable your mono output, find the two connected yellow AMP-Universal Power connectors sitting in the bottom of your cabinet, The female connector should have a small loop between pins 2 and 3, a red wire and a blue wire coming out of it. Disconnect the two, drop the female end to the bottom of your cabinet. You don't need it anymore for Stereo games (Don't cut it off, you will need it if you want to add a mono game at some point to this cabinet.)
Next, connect the Male end of those two connectors you found in step 1, and shove it into the Yellow connector on your power supply labeled "Sound Out". This connects your speakers to your amplifier. Do yourself a favor right now, grab that volume knob and turn it all the way down, so you don't accidentally blow your speakers out when connecting a game.
Our third step is to connect a loom of some kind to the amplifiers Input port, helpfully labeled "Sound In" and colored in a nice red color. I used the JVS conversion loom for my CPS 2 and Gradius IV kits, which works great for anything with RCA output ports, or a 3.5mm output port (Standard headphone jack, use a Headphone to RCA adapter, you can get those Anywhere.) For more annoyingly wired games, like Konami's older games which use a 4 pin JST connector, you will have to wire something up, But the stereo sound in Gokujyou Parodius is more than enough incentive to do that. Pins 1 and 2 are the left speaker on the 4 pin AMP-Universal Power connector, Pins 3 and 4 are Right speaker, use the manual for your game to determine where you should connect those pins.
Lastly, connect your game to the amplifier and Jamma harness, Turn your volume knobs ALL THE WAY DOWN and SLOWLY adjust them skyward once the game has booted (Use a sound test mode if you have one) so you don't blow out your speakers. Enjoy stereo sound!