Sonic Defender
Headphoneus Supremus
As far as I know, without an electrostatic headphone amplifier, an electrostatic headphone would require an electrostatic converter like the Woo WEE in order to be driven by a speaker amp. I can get the STAX amp for less than the WEE costs, much less buying a speaker amp. Not sure how your solution would be saving money.
My apology, my bad, I got caught up in speaker tap enthusiasm! You are correct.