I recently purchased a pair of KRK Rokit 5 Studio Monitors. I connected them via RCA to 3.5mm jack into my PC. They sounded great, except that they had a white noise/popping/crackling noise emitting from them that changed when I opened a program or moved my mouse. When I plugged the jack into my phone and played music from that, they worked beautifully. I did some research on the problem, and found that you needed an external DAC to fix the problem. I've purchased this DAC from amazon http/. I've connected my optical from my pc to the DAC, and RCA cables from the DAC to my KRK's. However, now I have a new problem. Whenever I play audio from my pc, the speakers emit EXTREMELY loud white noise. I've also plugged headphones into the DAC through its jack and still get white noise in my headphones. It's not the optical port on my pc because I've been using headphones with optical for about 2 years. You guys will either look at this post and majorly facepalm because of some stupid mistake I made (I'm not an audio wizard), or you'll be just as confused as I am. I also do not have much money to spend, so I need a cheap solution (not a $150 mixboard to run XLR through or something of that sort) Thank you very much for any support.