Shunyata Power cords Too Boomy and screechy?

High every one I have just bought a couple new power cords a year ago. And finally finished upgrading my intergraded amp to a high power tube power amp and tube preamp with phono. The power cords i bought are shunyata Zitron Vipers for my cd player and preamp and a Zitron Alpha Anolog for the power amp. Which I use on the preamp since it dose more good hooked up there. My speaker cables are Kimber 12tc with WBT gold bananas connectors. My interconnects are silver streaks with wbt ends as well.

I notice when i start playing female vocalist like Partrica Barber, Diana Krall and Ariana Grande, or most recordings with a piano, every thing starts to screech. And on the other hand some bass hevey or dynamic stuff like Michel Jackson, John mayer, Daft Punk, Sam Smith, Or Classical music it sounds like poping my woofers not even cranked up. Plus I don't have a quick system Cary SLP-98p CAD120s preamp and amp and totem forest speakers. And running kt-120 tubes which made the problems more noticeable.

I have tried trying out different interconnects that are copper and didn't make much of a difference. Then the main dealer I get most of my stuff from told me to try out the new Audioquset NRG-1000 power cords and three of them for my hole system. Which smoothed every thing out and all issues where gone!

The one thing is I'm stuck with now is what do I do with all of my shunyata cords. Which I bought from a different dealer that led me down the wrong path! Which I was lucky to go to an audio show. And got a 6ft NRG-1000 used in an audio demonstration, for around $900.
Has anyone had the same issue or noticed the same traits with shunyata?

I must say though that shunyata delivers the power to your system that it needs, but just harshens every thing up. Which the Audioqest gives you the power and without over powering anything and is more smooth detailed.
How did you burn in the PCs, power cords?
Connected to what load/s?
Amp draw of the load/s?
How many hours of break in time?

It sounds like you did not burn in the PCs properly. What you describe is how many after market PCs sound that are not burned in.

Example it took about 100 hours of burn in time on a Kimber Kable PK 10 power cord connected to a dehumidifier that draws about 5 amps.
My main system has 9 Shunyata power cords and 3 Hydra conditioners and I do not get any screeching or boomy bass. The Kimber silver streak cables are quite bright and wouldn't work in my system.
Burn in certainly could be an issue. However, if you are happy with the AQ cords, it seems that the simple solution would be to use the AQ cords and sell the Shunyata cords.

I buy and sell cords and cables all the time. Generally speaking, I'm not buying new from a dealer though, it helps to cut losses.
I have had them for just over a year and been playing fatefully at least 6 hours a day. And usually more then 6 hours on weekends. Plus my main dealer got my Kimber cables below cost. And trying to keep my interconnects and speaker cable all Kimber. And silver streaks bring out the best of my system. Though the nrg1000 just seamed to smooth things out with out loss of detail. I guess more suted for Kimber cables.
My experience with the Kimber Silver Streak was that it is a cable that can be quite glaring and that cable is probably causing, as you call it, "every thing starts to screech".

If you like the sound of silver try getting a cable which is soft annealed and uses higher grade silver. Such as .999 or better.
Try the Clear Day cables and get rid of the Silver Streak.