I just got my PAC-S10 and it works great.

Genesis games play flawlessly, as well as Sega CD games.

The problem comes in when I try to use optical audio.

I've heard that some PACs had problems such as only the music playing and no sound effects, but mine plays both... only in analog audio mode.

If I switch to optical audio, I only get the music. Is this the way it's supposed to function, or is my PAC bad and I'm lucky enough to be able to at least use analog?