Amps for Vandersteen 3A Signature SS or Tube?

It's shocking that no one has mentioned Quicksilvers yet. They are a synergistic match with Vandersteens. I've used a pair of the old quicksilver kt88s on this speaker before, and I don't doubt that their current equivalent (the mid-mono) would be a great-sounding, trouble free match. The V4 is another strong possibility: Richard Vandersteen uses a pair.

The Defy 7 is a great match and one of the best tube amps ever
made. Outstanding combination.

There are other threads on this...to sum up though, the best I've heard on the 3A Signatures are the BEL 1001 Mk Vs and the Quicksilver V-4 Monoblocks.

I have a pair !!!!!
My setup is Audio Research LS 16 mkll pre,
BEL Canto EVO (gen2)amp,Audio Research Cd3mkll CD player,
Vandys like yours,MIT interconnects and speaker cables-
The sound is dead neutral and oh so spacious and musical-
those speakers are capable of magic !
I installed a dedicated line for the system and put a Shunyatta Hydra 6 and use their pwer cords - Power Snakes-Diamondbacks mostly and an Anaconda.Really superb!
I cannot say enough good things about The Bel Canto!!!