Sounds like a grounding issue, two options.
1. Get a groundlift plug.
2. Get an external A/D interface.
I like #1 for the price, but #2 for quality. Audio output circuits in consumer computers are typically noisy. Two many power stages, and circuits crammed into a small space, that plus an emphasis on economy and good enough for most lead to compromises.
Wireless streaming to your reciever can work, but adds in a whole nother A/D and D/A step and adds compression to the data.