This can be dangerous!!!Does your home have properly grounded outlets? Check to see if there is a ground lift switch flipped. The Odyssey amps look like they have a grounded plug I think?You could call them and ask if they are. The ones on their website look like they do.
I have no idea about the preamp,or model.If you have a power
strip,try plugging everything in it.Also if you have a digital
multimeter(DMM),you could usually find them at home centers, Sears,for $20 or less for a budget one.Set it to check for 120
volts AC in the instructions.Try touching one probe on each amp or preamp one unit at a time,while the other probe could be touched to something metal that you got shocked on.Don,t touch anything while doing this except the plastic probes to the meter! If you get any kind of a reading over 10 volts from that piece of gear,a screw or something that is bare metal.That piece must be the problem piece. Also do this without any interconnects on them.The bad unit must be grounding through the interconnects. That is one probe touching preamp,the other probe touching a water pipe,furnace register,or anything that may be grounded.If you get a reading over 10 volts to ground or more,that piece of gear has a problem.Don't forget,touch the insulated probes only!This could be deadly!!!There may be 120 volts on one of your units.If your not comfortable doing this,don't! Have any friends that are electricians? Sometimes imported equipment doesn't meet UL standards.I'm leaning toward the preamp having a problem since you never had a problem before.Don't for get the lethal risk!!!Here is a link talking about ground loop problems.Link>>>>>[http://www.trinitysoundcompany.com/grounding.html]
