Here's a running list of electrostatic amplifiers our team has used with CRBN to good results:
Please note: Although the Stax amp listed has the "pro bias" of 580 volts and will work with CRBN, there are some (older) Stax amps that have both the original "Normal" (230 volt bias) and the "Pro" (580 volt bias) sockets. The CRBN requires the use of the 580 volt socket to work properly.
Mjolnir Audio Carbon/Carbon CC
Linear Tube Audio Z10e (also works with regular headphones)
Headamp Blue Hawaii SE
Eksonic Aeras / T2
Malvalve Headamp 3 MK4 (also works with regular headphones)
WOO Audio WES
For use with conventional speaker amplifiers to drive electrostatic headphones.
Woo Audio WEE