Preamp for McCormack DNA500

Hi everyone!
I'm in the market for a new preamp for my McCormack DNA500 power amp. So far I've been using my Benchmark DAC-1 but it's time to move forward. Only thing that concerns me is the relatively low input impedance of the DNA500 which automatically excludes (at least partially) major preamps such as AR Ref3, CJ CT5, Lamm LL2 etc, all requiring input impedances over 20KOhm. I've read excellent reviews on Tom Evans's Vibe Lithos 7 but cannot find anything on synergy with low input impedance power amps.
Any suggestions or comments most welcome!
a buddy of mine had some success mating a Vibe with his DNA-500 and using his Kharma speakers it sounded very good (at least to my ears). He always listens at lower levels than I do so I know it sounds good at lower volumes (if that matters).
How about the new McCormack preamp?
That's the first thing that came to mind as well; stay in the family.
If you can find one, the Audio Prism (or Red Rose) Mantissa preamp mates really well with McCormack amps. Yes, it's tubed. I know there are several posters with this combo (including myself) that wouldn't dare change a thing.

It has been around for 8-10 years now, but is hard to beat for musicality, transparency, quickness, imaging and bloom and such. The hard part, as I said before, is finding one for sale.

The SMC VRE-1 linestage is the first one that came to my mind also. I currently use an Audio Research LS-12 and like it very much with my DNA-1s but plan on buying Steves VRE-1 down the road some day.
AE-3 will compete at this level.. Try it you will see.

SMC VRE-1 was recently reviewed online at 6moons and Positive Feedback. Although I have not heard the unit, both reviews were very enthusiastic about its performance.

The only reason I mention it is because I'm very happily using a DNA225 with SMC Platinum and ARC-2 mods and consequently anything Steve builds gets my attention.

Plus, SMC is a great company to deal with.
Marantz SC-7S1 lush, almost warm with great detail and imaging. Running with a Wadia player and B&W 803D's