I have a Proceed PAV\PDSD, and use the remote feature to turn on my sourround sound amp. You need to use a mono mini jack. A stereo jack will not work. Also, you may need a steady current (not pulse), to keep the amp on. My PAV\PDSD allows me to switch from pulse to steady current through the menu interface. Not sure about the Proceed Pre, but check your manual...
Good luck.
Good luck.