when using short interconnects. Headphone jack what??? Get a "mini stereo to rca jack adapter" at rat shack, and insert it into the line output of your sound card. I use IC's with directional grounds, the arrow goes in the direction of signal flow, connect the PC line out to an Aux input on the Sony. My HK385i receiver tape out is also fed back into the PC's line inputs for dubbing Vinyl to CD. How long are your IC's? Would an extension cord to get the Sony and PC on the same outlet be too difficult(if they are in the same room, they probably are on the same circuit already)? Are you sure the noise is not being picked up in the long IC's, vs. being generated by a gnd loop? As Wayne mentioned...IMPEDANCE MISMATCH is very likely going from a headphone jack out into a preamp input. Sam