Re: USb interface background noise.
It sounds like a PC problem, in your case since both interfaces have the problem. I had an MAudio Fastrack Ultra 8R and dead quiet, no noise. USB powered interface units can have issues if there is not enough USB power, especially with Laptops.
Franklin D-10 Pedal Steel Guitar (primary instrument). Nashville Telecaster, Bass, etc.
ASUS Maximus VIII Hero M/B, i7 6700K CPU, 16GB Ram, SSD and conventional hard drives, Win 10 Pro and Win 10 Pro Insider Pre-Release
Sonar Platinum/CbB. MOTU 896MK3 Hybrid, Tranzport, X-Touch, JBL LSR308 Monitors,
Ozone 5, Studio One 3
Member of Nashville based R.O.P.E. Assn.