Quick question regarding audio ground pin

[Ed Oscuro]

When I was recently testing out voltages recently (all are fine, the +/-5V lines are just under and 12V is just on), I noted audio ground wasn't hooked up. I understand that the audio ground pin in JAMMA is the test switch on the MVS. It may have been with this in mind that Fire-bug didn't hook it up on my supergun, or something. Whatever the case, I found that Sengeki Striker (a cartridge/motherboard game) suffers an odd effect where sound effects start to distort and cover each other - cutting out entirely when there's a good amount of stuff going on. And Raiden Fighters 2 (another cartridge/motherboard title) wouldn't boot and froze the one time it did. All the "classic" PCBs I've tested work fine.

[emphatic]

I've read somewhere that some games "prefer" to use JAMMA ground instead of "SPEAKER -", quite often when it's a SuperGun. I don't care to elaborate.