Best Preamp to Pair with Acurus A-250 and Vandersteen 3 Signature Speakers

If I were you, hold off on selling that Acurus amp.

i disagree in this case

i would get whatever money you can from selling the acurus and put that towards something better sounding

the tubed preamp idea into the acurus, driving vandy 3a’s, is bad advice in my opinion.... you can spend alot of money on a tube preamp (good ones aren’t cheap) trying to feed the acurus and be worse off sonically and money-wise -- than going with a decent modern ss integrated

the vandy sig 3a is a smooth sounding speaker needing power and bass control, there are many fairly powerful, decent modern ss amps or integrated (ones without old school solid state sonic nasties) that will do very well and are more moderately priced than a good tubed linestage

Thank you for all of the good feedback.  To the one who asked, yes, they are 3a signatures.  They need a ton of power to control the bass.  The 2a signatures didn't sound bright with the A250.  They are just such a smooth speaker.  That is why I was hoping a tube pre-amp might do the trick.

I have 3a Signatures and run them with a pair of Belles Aria monoblocks and a Schiit Freya + preamp.  I agree with the recommendations to sell the Acurus and spend the $5K on a quality integrated or new separates.  Honestly, 2 Schiit Vidars (new model) as monoblocks with a Freya + tube preamp would be much better than a system built on that Acurus and would run you about $3K. Or you can also get a Belles Aria dual mono integrated with that budget.  But don’t spend $5K to get better sound from a (now) $600 vintage amp.  I bought my 3a’s used last year and continue to dial them in.  Great speakers.

To piggyback off @nymarty Johnny R is an incredible resource for both Vandy and Belles.  By all means give him a call, and especially if you’re on the east coast go to Audio Connection and have a good listen.  He won’t steer you wrong.  Best of luck.