Are these really Electret instead of Electrostatic? Difference? (Not familiar with, those technologies are exotica for most Headphone Nerds) (Post here so the other DROP buyers can see it, and, please don't say "do your research." This isn't FB.
VNTG-4UElectret as far as I'm concerned.
The main difference is the moving membrane is pre-charged on electrets, but electrostatic membranes has to be charged actively with high voltage (hence why you need an energizer to drive electrostatic headphones). Electrets' membranes are pre-charged, so they can be driven off regular amps.
Think of an electret as a cheaper cousin to a true electrostatic.