Yes, R3LL1K is right about the audio between a MVS setup and a JAMMA setup.
Normally pins J and 10 on the JAMMA harness are used as Audio+ and Audio- as a part of a mono configuration.
MVS however, uses J and 10 as both the Positive output for audio, instead as Left+ and Right+ for a stereo configuration that wouldn't require another cable harness like some Konami boards did. The Negative polarity of the audio is handled by the common ground so you could connect it to the power supply's DC ground, or pins A, B, E, F, 1, 2, 27, and 28 of the connector.
They both still use 8 ohm speakers though.