Another 'hum' thread...

I am running my Meridian 508.24 into a passive Adcom preamp, which then runs to a Merlin BAM, to a pair of Monarchy SE-100 Delux monoblocks and then to Merlin VSM-SEs. All interconnects are Nordost SPMs. I am getting an extremely loud hum from the speakers when I plug in the preamp outs. Strangely, if I wiggle the preamp out plugs the right way, the hum will completely disappear. I have to position the plugs just right, and it will go away, but if I bump the preamp and the plugs/cords move, the hum will come back. The hum is not dependent on the position of the volume controller. The preamp is completely passive, and hence, has no power cord. I have already lifted the ground plugs on the amps. The hum occurs whether I have the BAM in the circuit, or not. I assume that it has something to do with the RCA connectors on the preamp, but I don't know if it is something that I can fix or not. I have an old Pioneer receiver with preamp outs that I have hooked up to test it, and there is no hum with the Pioneer.
Do you have any suggestions?

Thanks in advance,
-Kurt Jeffers