After going through several design iterations, we're close to finalizing a simple 3 input (2 output) companion switching board for the LDR3x preamp controller board.
Below is a summary. If you have any thoughts, wish lists, must haves, can't stand, can't live withouts etc, now is the time to pipe up with your input.
1) Switches between 3 stereo inputs using control signals from the LDR3x
2) Provides for connecting 2 outputs in parallel
3) Left/right channel grounds are kept separated (should each be tied to power/chassis star ground)
4) 0.1 inch pitch screw terminals for landing inputs/outputs/grounds
5) as alternative to 4), also has solder holes for terminating I/O plus ground
6) 0.1 inch pitch screw terminal for interfacing with the LDR3x board
7) Uses LDRs as signal switches in lieu of electromechanical relays. Roughly 40-60 ohm resistance when on, several megaohms when off.
8] Control/power interface with pin/jumpers to the LDR3x. Note that the LDRs have to be current limited when switched on. This is handled by 6 diode/resistor pairs that need to be installed on the LDR3x board and will be provided with the IOBoard.
9) 1.6 by 2.5 inch board size