Mikhail

Hi guys! I buyed Klipsch R6 On-Ear Black and have the problem... I hearing hissing when i pluged my headphones to my pc. I've buyed USB DAC(Asus Xonar U3) but already hearing hissing! When i plugged my headphones to another laptop i hearing same hising(p.s. i hear hiss when nothing is played). But when i'm plugged my R6 to iphone or ipad hiss is gone! So i think problem with sound card? What sound usb card you can suggest me? I want good budget variant.