This page describes the procedure for wiring up the sound signals from your Gauntlet PCB.

This document assumes that the reader has at least a passing familiarity with crimp-on connectors. I recommend Bob Robert's Crimping Page to those who have never used these connectors before.

Wiring up the Sound connector (PST)

The Gauntlet PCB generates unamplified stereo sound output, which is amplified by a separate board and sent to two speakers in the Gauntlet cabinet. I do not have this extra board, and I only have a single speaker in my JAMMA cabinet, so I will show you how to wire up the PCB in a mono JAMMA cabinet. I'll also try to provide some information for other setups (e.g. stereo JAMMA cabinets).

Cabinet with a Mono speaker

If you have a single speaker in your cabinet, you will need an external amplifier to drive this speaker, as the Gauntlet board generates unamplified sound. This is a useful thing to have in your cabinet anyway, as several other classics (Mr. Do! series, Donkey Kong series) also require an external sound amp. You can build your own using an LM380 as described in the conversion FAQ, or buy a pre-built one from various sources. I built one from a kit I bought through Jameco for $10, which runs off the existing 12V supply in my cabinet. I don't want to go into too much detail about how to wire up the amp to your speaker - if you don't think you can figure it out, you might want to explore one of the other options I list at the end of this document.

Once you have an amp installed in your cabinet, all you need to do is convert the stereo signal to a mono signal. Some people suggest just tying the two stereo signals together, but to be safe I run them through a pair of 2K resistors (the exact value doesn't matter - either 1K or 2K should be OK, as long as both resistors are the same value), so we don't stress the PCB by having two parts trying to drive the same piece of wire to different voltage levels.

Here's the circuit you'll build:

I just built the circuit on a little breadboard I bought from Radio Shack for a couple of bucks, but you could probably just solder the resistors directly to the wires without any problems. Just make sure you insulate them so you don't get any shorts.

You'll need an 11-pin .100 inline molex connector - as usual, a larger pin count (like a 12-pin connector) will work fine if you just ignore the extra pins. I broke off a toothpick in the 3rd pin housing to mark the "key" pin. One note - this connector has the key on the 3rd pin, just like the PVIDEO connector - to be safe you should mark the connector as PVIDEO or PST so you don't accidentally swap the connectors.

Wire up your connector like this:
 

Pin on PST header	Color of wire I used in my adaptor	Signal	Position on JAMMA fingerboard
1	-	-	-
2	GREEN	Test switch	15, Comp side
3 (KEY)	-	-	-
4	WHITE	Audio (left channel)	to "Stereo left" in circuit above
5	BLACK	GROUND	to 'speaker -' input of amp
6	WHITE	Audio (right channel)	to "Stereo right" in circuit above
7	-	GROUND	-
8	-	Coin Counter 1?	-
9	-	Coin Counter 2?	-
10	-	-	-
11	-	-	-

When you are done, it should look something like this:

If you make the connector and the resistor circuit above, you should now have unamplified audio and a reference signal (ground) to feed to your audio amp. Just connect these signals to your amplifier, connect the output of the amp to your speaker, and you are done!

Cabinets with Stereo speakers

You'll either need a pair of external amplifiers (or one external stereo amplifier), or else you'll need to obtain the Gauntlet aux board, which contains a stereo amp. I do not have the Gauntlet aux board, so I do not know how to wire it up. I have heard rumors that you can just connect +12V DC to the 12V AC and 15V DC inputs, and -5V to the -15V input, but I have not verified this, and in fact I have no first-hand information about the aux board at all.

If you have two external amps in your cabinet (or one stereo amp), you can wire them up to the board in a similar manner to what I describe below for a Mono speaker cabinet, with the exception that instead of tying the left and right stereo signals together via resistors, you should route them directly through your amplifiers.

Other options

For people that do not want to deal with wiring up an amplifier in their cabinet (if you've made it this far, you are probably quite capable of doing the wiring) - you can just add some self-powered amplified PC speakers to your cabinet, and wire them directly to the sound output. I haven't done this, but I've heard that it works pretty well. Radio Shack sells a number of different speakers of this type - some part numbers to check out are 40-1404, 40-1407, and 40-1408.

Congratulations! You've finished your adaptor - I've not seen such bravery!

If you have any comments or suggestions for how to improve or extend this document, please let me know. Thanks!