The set of grounding leads you got with the empeg (the ones which fit at the amp end) - there are 2 sets and you may want to do the fix on either the one which drives your subwoofer or both.

Open up the plug end of these - the hoods unscrew. Inside here you fit a 1k resistor between the 2 terminals. This can be done pretty neatly and the top should still fit back onto the plug.

That's it really. The resistor doesn't dissipate much energy so any old 0.125w will do.

Hugo