Audiodharma make a suitable set of adaptors (RCA to USB) for use with their cable cooker, and while you’re at it might as welll buy the cooker as well, it is well worth the $
http://www.audioexcellenceaz.com/products/audiodharma-cable-cooker-cable-conditioner/#tabs-12-0-2
cost is $95
http://www.audioexcellenceaz.com/products/audiodharma-cable-cooker-cable-conditioner/#tabs-12-0-2
cost is $95