Tube preamp options

Backert, VAC, ARC Ref6 all are worthy contenders. I'd search hard regarding VTL service issues before considering. 

ARC is known for synergy with Vandersteen...a proven winning combo for many. IMHO this is partially because the Vandy adjustability allows tailoring that may offset the ARC erring towards the drier, more clinical SS end of the spectrum vs. the others mentioned. 

VAC Ren V w/phono is what I recently purchased, vs. BAT previously. I'm experimenting with tube rolling on the phono side, but happy with the vintage Amperex Orange Globes that came with mine on the line stage side. IMHE, both the BAT & VAC are tonally a bit warmer, fuller than the ARCs I've heard including the Ref 5 and earlier, but not the 6. 

The Backert is also fantastic and perhaps tonally between those others, with tremendous rhythmic drive and plenty of air on topic. They are single-ended designs, so if running a balanced amp, there's a disadvantage there.

OTOH, As a longtime friend of the Backert team, I can attest to their knowledge and experience is far greater than some might assume with a relatively newer company vs. these other legends under discussion. There products are so good that local audio club members in their area have flocked to own the preamps after hearing them in many friends' systems over many pricier competitors at a rate I've never seen of any other audio product. 

You've got options! Cheers,

Spencer

I wanted the same thing and got a 6SN7 based pre and love it. Take a listen to deHavilland (hard to find) or Don Sachs (sometimes used) or Aric Audio as possible options. Aric writes right back and will custom make things. 

One other consideration is your room. I have done a lot of experimenting to get soundstage depth and room factors play a large part. You might search within this forum or elsewhere for replies to this question.

@sbank thanks for your thoughtful info. You may know something I don't know about the backert. I think my long term goal is to replace my m180s with the vandersteen bespoke amplifiers. I've heard they are absolutely unbeatable but they are balanced. Looking at the backert products, they have balanced in and out so I thought they were balanced units. Is that false? Did they jerryrig the circuitry to add balanced I/O to an unbalanced design? 

Also ony list but it's impossible to find to listen to would be the Brinkmann Marconi. I've been extremely impressed with the TT and wonder if the electronics are of the same caliber.

Well below your budget and even less if you buy direct, the Herron VTSP-360 is excellent.