Certainly seems that there is a difference. I've had an idea, but have no idea if I'm on the right track.
Spielmanszug is definatelly THE military band, used for military purposes, parades etc.
The Musikzug could be the more informal band, ie., the band used for dances in the officers mess, public performances etc., etc. I guess its composition would be made up of members of the Spielmanszug. But why a different leader.
Now I'm as confused as you are.
Hope someone can clear it up.
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