Vandersteen 3a Sigs, McCormack DNA 125, preamp?

What price range?

Audible Illusions L-2 or M3A if price is a concern. If not, then look at the Aesthetix Calypso, ARC Ref.II or one of the BAT's (31se or the 51se) I'm sure they're others to recommend but I have actually used these. I do think the McCormack benefits from tubes.

BigTee speaks the truth. McCormack and Vandy's want tubes. I would add First Sound to the mix.

Modwright SWL 9.0 SE Tube Linestage. Highyly recommended.

If price is a concern, I would highly recommend the Audio Mirror Tube Preamp. It retails new for about $700.00. Vladimir sells direct and builds VERY nice tube gear.

How about a TAD150?

Try VAC - I've had 2 of their preamps now with my DNA-500 and sonically the match is wonderful. Kevin Hayes is also great to work with and his gear is built to last a lifetime.

There are a number of people on this forum and I imagine elsewhere that have very successfully paired VAC preamps and McCormack amps.

Another vote for Modwright. I used it with a McCormack on 3 sigs. Great preamp.

The Audio Mirror is a nice pre and I heard it with several speakers but, my vote would go for the TAD-150 especially if you play vinyl. I have both the TAD150 and 60 and drive Vandersteen 2CE signatures....

I got very good results with an Audio Research SP16L along with the 3asigs and DNA 225

If you go tubes, I'd suggest a Herron VTSP 1A/166 because you ARE going to need the finely incremented volume control with the McCormack amp and, from epxerience, I know these two components match quite well with Vandersteens. First Sound is another fine suggestion.

Do not forget about passives. A Bent Audio NOH would fit in VERY nicely, IMHO. Make sure whatever passive is transformer-based, though, or you will sacrifice dynamics. Rumor has it that Steve McCormack will be comingout with a SOTA linestage one of these days, himself. I am waiting to try one, myself. :-)