I dont think there is a "save button" on the bryston sp-1 remote
There isn't. I had an SP1 for years before upgrading it to an SP2.
Switching to a different source auto saves the settings of the source you are exiting. Also a shutdown will save the present sources settings. There were a limited number of saveable settings though.
Certainly
each source allowed speaker configuration, Xbass setting, rear channel levels, subwoofer level, bypass status, thx status, and listening mode of either (Digital (Auto), ProLogic, Stereo, Mono or Music). You had to setup each source and then switch to another source to save it. If you were playing around with your settings and inadvertantly switched to another source, it would resave (a bit annoying).
Since DTS music was a function of the Music Mode, it would require the dts bitstream to revert to dts, but it would always require cycling to get out of dts music (as I remember).
My advice, upgrade to the SP2 - a different world altogether......
brucek