Originally Posted by
mattking52
For the record, there are actually six 'bridges' on the switch connections, per the schematic and the PCB.
It looks like Dev has already figured out the wiring, but in case it's helpful to anyone consulting this thread later, I'm including a diagram here that I used when removing the switch and replacing it with individual wire jumpers. The black connections (drawn on the PCB) denote the placement of the six jumpers for full passive mode ("Internal Crossover"), and the red connections denote the placement of the six jumpers for bi-amp mode ("External Crossover"). I tried the wires in both positions, and confirmed proper operation.
I've long since moved to a bi-amp configuration with a First Watt B4 and my own charge-coupled external crossover PCBs. Dev: I highly recommend the charge-coupled, bi-amped configuration as part of your explorations with your 4345s. Have fun and enjoy the ride!