Peavey’s TL604 Adapter Kit.
You will need soldering iron, solder and a bit of installation ingenuity (parts and instructions included).
The TL604 dual analog switch is obsolete and no longer available. Please note that this adapter kit will effectively replace the 604 and provide the same functions required in Peavey products. The only drawback, of course, is the size of the board versus the original part.