Chunkulus,
Please post again here if you ever get this figured out. I've build two different styles of switching systems so far the past year and a half. One uses PNP and NPN transistors to switch LDR's on and off, the other uses Integrated chips to switch LDR's on and off.
Both of my circuits work just fine, and they both have their pros and cons.
The PNP / NPN switcher is nice for small numbers of LDR's. Quick and easy build, but I don't trust it to run the number of LDR's in my new build, so I came up with the integrated circuit switcher.
The new switcher uses a 7404 inverter to interface between the footswitch/and/front panel switches, the inverter sends a signal to a 573N octal latch, which does the actual switching, and the octal latch sends the signal to a 2803 darlington driver chip. The LDR's "could" possibly be ran from the outputs of the octal latch, but I'll be running about 28 LDR's (and front panel and footswitch LED's) for the 4 channel switching on this build, so I've added in the 2803 chip, because it's MEANT to drive bigger loads (current).
I've got this circuit up and running, on breadboard, and PC board. (blue goop on PC board is RTV silicone)
I don't have the amp built totally, but I'm confident in this switcher, I've ran it for hours on the breadboard.
I've searched and searched for ready-made systems for channel switching, always come up empty handed.
https://drive.google.com/open?id=1oUemxfybH6QiTEFrnAX0BEZCjCF-mAM7https://drive.google.com/open?id=1FQ4Raw6WQMxQvB-MOdd9fLmr--VQ2CT1https://drive.google.com/open?id=1fXpLseDODCohku4qQCWDbCAnh8rlSPNqhttps://drive.google.com/open?id=1OP21_bLN3FP0Ot0I1x_yFhESIUZf-CyC