Have you asked C-J? They're pretty good at getting back and providing any info they have, try them via their website. conradjohnson.com Good luck.
c-j technical questions
Does anyone know of any tests that show the power out-put of conrad-johnson's solid state power amplifiers into a 4 Ohm load. I'm particularly interested in the 2300, 2300A, 2500 and 2500A amplifiers. I'm also interested to know what the out-put impedance range preceding these amplifiers should be.