j-wall glad to hear you solved your issue. Good advice from Whart as well!
I rolled the stock power tube on my h3000 with a NOS Mullard years ago and got a huge bump in performance in my system. Frankly, I was shocked that it could make such a difference.
Good luck with your journey with power cables - I also believe the same brand should be used throughout. I have tried an embarrassing number of IC/SC but not a lot of PC’s. I have stuck with wywires for all components and have been pleased. I also plug everything into a Shunyata Denali V2 fed buy a Sigma XC PC. This was also a big bump in performance in my system.