Shunyata new VTX

Neither.
The Hydras VTX's are power cords for the power conditioners, like the Triton, Talos, and Hydra series.
The Black Mambas have been superseded, but not replaced, by the new ZiTron Cobras...

Shunyata research told me that the Hydra HC VTX power cable is not a direct replacement for the black mamba, but I was also told that this cable is preffered over the black mamba. The new VTX geometry was developed with the DTCD test device. These new geometries are suppose to be the best incarnation of the Shunyata line. The Hydra HC PC is lower cost than the black mamba because it doesn't have the fancy wrappings. While the Hydra HC is certainly perfect for the Hydra units themselves, I was also told the Hydra HC VTX is great on amps. Remember - the VTX geometry replaces the older CX geometry.

Just got two 15 amp HC VTX for my amps and one 20 amp HC VTX for my hydra 4. They are being broken in with a fan but I've been hooking them up in between time as I can't resist. So far better bass and a more authoritative presentation. Previously the amps were fed by AQ nrg 10s and the hydra 4 by a diamondback 20 amp. It appears that there have been no trade offs as tonality is intact and nothing funny is going on anywhere else. A word of caution though they are a stiff cords and relatively heavy.