As of tonight, my ZMA has a selector switch.  works and sounds great.  I have my good DAC loaned out but with my backup DAC, it is sounding great.  
Tonight I switched to movie mode for the first time since I got the ZMA wihout having to swap cables.  Works and sounds great.  
While I was in there I replaced all the signal cables with Mundorf Angelique (silver, gold, copper) wire.  I also replaced the RCA connectors with  KLEI low mass connectors.
Here is a photo of the switch and the new connector. The switch is just in front of the output transformer, one per side.  Looks great.
https://share.icloud.com/photos/0813QSD5UrSOREOOdhgtmSFkg