Best amp for Von Schweikert VR4SR mk2?

You might try McCormack's new preamp, which wasn't around when I was using his amp.

For my VR4SR's I use Nuforce Reference 9V3 SE monos and with proper vibration control (Hyperion Magnetic floaters) and mass loading (5lbs diving bag on top), they sound great. These tweaks are necessary because the amps are only 7 lbs each. Can leave them on all the time as they draw 2 watts at idle so are always ready and warmed up, and take them to friends houses easily to compare and for fun. Front end is Ayon CD5s. These amps are able to control the speaker really well across spectrum and allow it to express finess and naturalness.

I believe that these speakers were developed with Spectron amplifier. I know that John Ulrick of Spectron has these speakers and use his his Musiican III Mk2 (stereo) with them and thus I suspect that there is a great deal of synergy between them.

Good Luck

Simon