I am still running 110 with mame32FX
try your version with the FX os and see if it is available then.
I use it becuase it balance's all the volume's out.
I hated it when one game you have to crank it up just to barely hear it and then when you start another game it sounded like the speakers were going to blow becuase it was up to high from the last one.
this way you set it where you want it and get the same volume level for all games wich is much nicer plus you dont have to keep farting with volume control all the time..