Hi Steve,
the Mini VBar was first not designed for use with the VBar Governor.
We did then re-program one of the servo signal inputs on RXA (used with standard receiver hookup, one wire per channel) to accept the RPM signal when the port was not in use (e.g. with a single line receiver, or Spektrum sats).
But RXA was designed to to work only with < 5 V of signal gain, which was OK for servos (as an output).
So on a Mini VBar, you would have to verify that the input signal is < 5 V, or use a voltage divider if you were to use HV (2s LiPo or HV BEC).
If you are not sure about the ESC together with a Mini VBar, you can check the signal voltage on a lab scope, maybe even with a volt meter (it will probably show half the actual voltage, because it's clocked).
With the full size VBar black, blueline, silverline as well as the VBar NEO, there are no such limitations.
Kind regards
Eddi
Born to fly ...
forced to work.