The Muzak (TM) box my wife gave me was mono. Maybe they do stereo but not at her place. It also had 70v and regular 8 ohm outputs.
The 70v was bad but the 8 ohm still worked. My neighbor is using it now. I coupled the stereo line level input from an MP3 player through a ground loop filter (pair of transformers) to a "2 for one" RCA cable and it seems fine. I was concerned about tying to outputs together directly too.
I think this box only has outputs to feed an Amp
