Line level (unamplified ) audio from Jackie Chan arcade boards

Categories: [blog]
Tags: [arcade], [modding]

The Jackie Chan fighting game arcade boards produced by Kaneko (Kung Fu Master and Fists of Fire) both only output amplified stereo audio output - both from the Jamma header and from a 4-pin header on the motherboard near the amplifier heatsink.

Many arcade cabinets and supergun setups these days prefer unamplified, line-level audio, and here's how to obtain it on these boards.

Jackie Chan PCB image

The trimpot to the right of the image adjusts the level of the amplified audio - or more accurately, it adjusts the level of the audio input to the amplifier. I believe the input to this trimpot is roughly line-level, and so suitable for our needs.

If we say the pin on the trimpot closest to the edge of the board is pin 1, then:

If you want control over the volume on the board, then tap pins 3 and 4, otherwise 5 and 6.

There aren't any great places on the board to mount the jacks, unfortunately - in this case I had some which wedged into the heatsink fins pretty much perfectly though. Whatever works...

For those interested, the power amplifier is a Toshiba TA8210, with a pretty reference implentation surrounding it (as seen in its datasheet).

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