I added a separate passive pickup, volume pot and output jack to my passive Spector Performer bass (bridge and neck passive EMG pickups). Each original pickup has a separate volume and tone pot, so 5 pots all together and 3 pickups. The share the common ground, which is the bridge. When I plug one output jack to one amp and second output jack to the second amp, I get a ton of hum and buzz. It does not appear that anything is inappropriately touching anything it shouldn't. Any ideas what the problem could be or how to fix? The bass amps do not have polarity switches... Thanks!!