Ok, before you go ripping out wiring or amps in search of the cause you should eliminate the empeg as a possible cause.

An eq bug recently came to light whereby if you have the L and R channels 'locked', the player gets it wrong, and the channels end up with different frequency and q values. It is apparantly fixed in the next release. So, if you created your eq with the channel lock on then your settings could be inconsistent between L and R. If you had channel lock off, then L and R will be correct to whatever you set them to.

So, try selecting one of the flat unmodified eqs, and see if you still hear the 'static'. If you don't, try to recreate your chosen eq with the channel-lock turned off. Swapping left/right is also a good diagnostic idea (as you have already realised.)