I have to agree with boxer12 and jbrrp. Over the past 20 years, power cords have made the largest impact in my system when it came to cable upgrades (i.e., ahead of IC and spkr wire). Depending on your box count, IME the first place the cord should go is the amplfier and a close second on your digital source (with a PC designed specifically for digital gear).
On another point, off topic a bit, is the use of isolation transformers. I've owned several well known PLCs in the past, but the most effective by far is an isolation transformer. While there are several audiophile approved companies making them and audiophile prices upwards of $2K, I found a hospital grade Powervar iso xfmr on Ebay for a tad over $200. I put in some better outlets/wire and WOW! Line noise gone, lower noise floor, more texture, etc.and no downside. Granted Imy amp is only 100w/ch, but larger iso xfmr are available.
On another point, off topic a bit, is the use of isolation transformers. I've owned several well known PLCs in the past, but the most effective by far is an isolation transformer. While there are several audiophile approved companies making them and audiophile prices upwards of $2K, I found a hospital grade Powervar iso xfmr on Ebay for a tad over $200. I put in some better outlets/wire and WOW! Line noise gone, lower noise floor, more texture, etc.and no downside. Granted Imy amp is only 100w/ch, but larger iso xfmr are available.