Buzzing IC's

RCA.

@cetla416,

Example, look like these?

Are the IC cable RCA plugs hard to push onto the RCA jacks on the ARC LS25?

Looking at the plugs they look like they would be.

Just a guess you are not pushing the plug(s) all the way onto the RCA jacks on LS25. Center pin of the plug is not making a good contact with the center contact of the jack. Try pushing harder to make sure the plug center pin is seating correctly into the jacks female hot signal contact.

Try connecting one cable at a time and see which one buzzes. Sounds like a defective cable. 

It’s the second set of cables reacting the same way. I’ll try one at a time and pushing in farther if possible.

Just a thought here.  Are you following the Arrow markings of the cables?  Signal flow From-To.  On the Source, preamp side, the cable Shield and Signal Ground wires are connected together.in the rca  On the subwoofer side connector, just the Signal wires are connected in the rca.  The shield is not connected.