Pioneer cd changer with JVC H/U with cd controller?
Assuming you have auxilliary input on the head unit (not all JVC decks have that) or that you can find a cable to connect to the bus then the direct connection isn't really a problem.
However, providing a direct audio connection for the audio has nothing to do with controlling the changer. You will not be able to change discs or tracks from the JVC head unit. That model of changer is designed to work only with a compatible Pioneer head unit.






