Do I need upgraded power cables?

I have had a good experience with the Cardas Parsec XLR interconnects and speaker cables, but your experience may vary if you are looking for a different sound quality from your cables. I think it's great that you are using the Lending Library from the Cable Company.

Several years ago, I borrowed interconnects from the CC and tested them in my home system. I listened to the Cardas Parsec, the Shunyata Venom, a cable from Synergistic Research, and another cable I can't remember at this time. What I do remember is that I liked the Parsec best. It had a smooth, musical delivery with absolutely no listening fatigue. In contrast, the Synergistic cable overemphasized the high frequencies in a way that was fatiguing and lacking in fullness of tone. The Venom was at the opposite end of the spectrum, sounding very smooth and pleasant, but not being especially lively or engaging. The Parsec was the closest to "just right" for my system and my preferences at that time. The Parsec had enough smoothness and richness to help tame my Thiel metal tweeters without excessive softening of the high end.

After living with, and enjoying, the Parsec XLRs and speaker cables for a couple of years, I decided to move up to more expensive options in the Cardas line of cables. I decided not to go all out on high-end detail, but I wanted to add a bit more transparency and openness without giving up too much of the Cardas' rich tonality. I settled on Clear Reflection, despite it being substantially more expensive than Parsec, and I have been very happy with Clear Reflection in my system.

I am currently testing out a few power cables I borrowed from the CC Lending Library. I have been quite impressed with the Shunyata Theta NR cables, although I wish they had just a touch more "meat-on-the-bones" for my taste and system. I'm afraid I'll have to spend more to move further up the Shunyata product line, but the Theta power cords are definitely a great value. I'm currently using Shunyata Delta V2 NR and Venom-12 NR power cables on most of my gear.

I think you are on the right path in trying out cables in your home system to see what sounds best to you. It's easy to be seduced by high-end detail, and too many cables go over-the-top in a way that is not very realistic and can become tiring to listen to. In your listening, be sure to pay attention to which cables help draw you in for extensive listening to your system. You want to select cables you can live with, not those that provide just an exciting "one-night stand."

I would encourage you to borrow the Acoustic Zen Satori cables and Matrix Ref. II Interconnects for reference if nothing else.  If you can find cheaper cables that can match those then you’ve really got something.  Best of luck in your search. 

I use the Cable Co. a lot.

What has worked for me is to borrow usually four cables at one time. I do a fair amount of research to try to narrow choices down to near four.

Because they are already burned in, I don’t have to wait for each one to sound the way it will forever (and its best).

Then I try each one for 2-3 days, listening to very familiar recordings, and taking notes.  Lots of notes.

Then when I have to send them back, I try to pick my favorite.  Most often, one of them is outstanding and sounds exactly like what I had hoped.   Sometimes, none of them sound like what I had hoped for, and I have to start over with another set of four. 
 

This strategy has certainly worked well for me.  I get exactly what I want—because I tried it in MY SYSTEM.  No surprises.  No disappointment.  
 

(Plus, the Cable Co. applies the rental fee to your purchase, so no loss.)

"Do I need upgraded power cables?"

Tangible “upgrade” sure, go for it!

Cable has to be compliant with manufacturer's IEC design, safety / UL is important too. 

Hello, and I hope you are well. You have a nice system. I would go to Amazon and purchase power cables (brand is Preffair and visit their site) for your amp and subwoofers. I am not affiliated with this power cord company or Amazon. I did build power cords, as it is not difficult, but time consuming. After the price of connectors, good cable by the foot/meter, and the dressing.....you are way beyond these Amazon prices. Your factory power cables are "bottlenecks" to the full capability of the components. 10 gauge cords, will make a huge upgrade. A nice "intro" to the power cord thing. You can select the plug material coating and the specific plug housing you want. I use the Alloy shells with the Rhodium plugs, which sound a bit more extended in the treble compared to the copper plugs, ime. I talked about these before here, and a few folks contacted me thanking me. Someone did not like them, as they were using much more expensive brands. Hope you try, at least one, for your amp. My best, MrD.