Help selecting a power cord.

You ask good questions. I have had some form of upgraded power cord for so long i forget which is most sensitive but I have recently been doing some upgrades. What is your equipment? You want to be investing in cords that raise the performance level enough that it would not have been better to invest in better components. Yes, power conditioner is probably the first step.

Shunyata, PSAudio, and Hydra are some to check out. These are not products to go cheap on. You should either try a couple from a dealer or get with return privileges. It should make a significant improvement. If you get a really good one, it can outlast many component upgrades.

.

Then comes power cords, they are like interconnects, which cord sounds best is dependent on your equipment and tastes. It is imperative to try them. I would get at least 4 different brands... rent or borrow. Shunyata, WireWorld, DHLabs. Since you have tube equipment I am guessing you are not looking to warm up your system... that leaves out Cardas I think. Although the new Cardas Clear Beyond seems to through off the typical warm and lacking in details stereotype.
I would get two pair of each and put on preamp and amp. Typically the low power digital components would have a different type (noise reduction... and they don’t have massive current). I have used DH Labs silver as inexpensive cords as standard until I have time to evaluate. I think they are among the most cost effective. But they need lots of breakin time.

.

The decision of if the power cord is worth it should be easy. The performance increase should make you say, “wow, this is a good deal!” I have said that about $1,500 power cords and $2,500 interconnects. If it doesn’t then keep looking or just wait until after your next system upgrade.

Looking over your equipment power cords may make a difference, maybe not. I would look in the $300 range... no more. If you spend more, then the money would be better spent on upgrading components. DH Labs on amp Power Plus and Preamp would be a good place to start. If this doesn’t have a significant positive impact... then they are good solid investment on your next generation system. 
.
If you listen to streaming... my next investment would be a high end streamer. The Yggi is capable of a lot with a better input. Aurender makes some outstanding streamers at every price point. 

If you can’t instantly hear the difference in a blind test, then you shouldn’t buy it. Unless your system is at really high levels of performance and you are comparing expensive to very expensive power cords... it should be a no brainer. Most of us who have built great systems over many years remember their first digital cable, analog cable, and power cord upgrade moment... the moment we went “holy cow, how can a power cord make that much difference?”. If you don’t get that... just keep working on upgrading components.

+1 Duckworp

@budburma 

+1 on effects of power cords. I have optimized my final system multiple times through 1. Speaker cables, 2. Interconnects, and finally 3. power cords.  Each time the final system was very significantly better at the end… by at least a component swap level because of it. But in different systems… the same cords and interconnects would not have been optimal.