Why do I get high-pitched sounds in Marvel vs. Capcom with Darksoft multi? [RESOLVED]

[Arcade-Projects]

I installed my Darksoft cps-2 multi today. It is working great for every game I've checked, except for Marvel vs. Capcom. In Marvel vs. Capcom I get annoying high-pitched audio tones in addition to the normal sounds effects and music.

Check out the video: Capcom cps2 marvel vs capcom sound test

My cps-2 A board is Japanese. The B board is a USA (blue case) revision 4. I'm using a HAS supergun. Audio is mono through the JAMMA edge. The ROMs are from the CPS-2 roll up pack (dated 2019-09-18) found in this forum.
arcade-projects.com/forums/ind…e73a1dfccb5e6e7f911a58a72

Any ideas?

More...