I tried a Venom HC (v1) power cord on an Isotek Aquarius power conditioner. It provided a significant improvement to the sound over the as-supplied Isotek Premier cord.
I also spent time listening with Delta NR v1 and v2 cords as well as an Alpha NR v1. Sound with those was better than with the Venom HC...but not by as much as provided by the Venom HC over the Isotek Premier.
Ranking would be...
Delta NR v2>Alpha NR v1>Delta NR v1>>Venom HC>>>Premier.
No experience with the Black Mamba.
Though I have not tried the latest version of this power cord, I believe the Venom HC is an outstanding value.
Hope this info is useful.
I also spent time listening with Delta NR v1 and v2 cords as well as an Alpha NR v1. Sound with those was better than with the Venom HC...but not by as much as provided by the Venom HC over the Isotek Premier.
Ranking would be...
Delta NR v2>Alpha NR v1>Delta NR v1>>Venom HC>>>Premier.
No experience with the Black Mamba.
Though I have not tried the latest version of this power cord, I believe the Venom HC is an outstanding value.
Hope this info is useful.