Having owned the Paradox for some time now, I have been investigating a speaker amp to drive them, after having been impressed when using my Musical Fidelity A1 amp off the speaker taps. Since my Paradox are wired single ended, the amp needed to have shared negative common grounds. I did a bunch of research and came upon a relatively inexpensive amp (by 'high end' standards) by TBI called the Millenia MG3. I've included some links to reviews about the amp that compared it to some pretty esoteric SE tube amps and even some Pass Labs class A amps. It costs $500 and there is a 30 day trial period.
Even though it was not designed for headphone use, and the negative taps are not shared, the designer was happy to work with me to give it a try. First I tried it with some resistors to help with the grounding issue and to diminish background hiss from the gain of the amp. Then Jan (the designer) came up with a box to go between the amp and the headphones (with a resistor network to both take care of the negative grounding issue, the background hiss, and the impedance issue of the headphones). Now I believe this amp with the Paradox headphones is providing me with some of the best hi fi music reproduction I have ever listened to, since getting into the audio hobby in the mid 1970s. Although I am new to headphone use, I have owned in the past various top of the line Stax Lambda headphone set ups, but mainly have had some pretty nice stereo set ups (Magneplanars, Quad electrostatics, various Spendors, tube amps both push pull and single ended, etc., etc.) I have a pretty good idea about what constitutes good sound.
Also, Jan was outstanding to work with. He really wanted to help make his amp work, even though driving headphones was not what the amp was designed to do; others may well have suggested I look elsewhere. Oh, and the amp can work off 8 AA batteries (with 10 watts/8 ohms rather than around 30 watts on ac). Some prefer it on batteries. Either way, a phenomenal amp.