Tube Preamp Recommendations?

I have a Tube Pre-amp with Tube Power Supply for Sale an alternative choice would be the Atma-Sphere Gear which is world class in my opinion the amps and pre-amp will perform at a league not many can compete on.

I think the OP already bought an AR SP6b. Just curious to hear how he likes it... This is of course if he ever returns back to post his impressions.

Thanks for all the responses. I indeed purchased an AR SP6b.  The sound is wonderful.  I also purchased around the same time an AI L3 dealer demo directly from AI.  AI is upgrading the power supply and some internal caps so it will more or less be an L3A.  The unit still hasn't arrived.  I'll post my impressions after I receive the AI.

Thanks for your patience.  The L3 took a lot longer to arrive than expected.  It is an L3 dealer demo that went back to AI where it was essentially upgraded to an L3A and then sent to me.  

I love so much about the AR SP6b, particularly the bloomy midrange that works so well with my ProAc Response 2S speakers.  It especially shines with vocals and acoustic instruments.  It feels like the tubes are backed by an enormous reservoir of power that effortlessly pushes out warm notes that suspend in the air for just a moment before the next note.  I can listen to the thing all day long; it's really enjoyable.  What it is missing, however, is detail, particularly in the high end, and imaging.

The L3+ has that detail that the SP6b is missing, along with the imaging. The build quality is exceptional.  But it feels dry, flat, or maybe sterile, compared to the SP6b.  It's probably more accurate than the SP6b.  In the right system, which would probably be mega $$$, I might prefer that accuracy.  But in my system, it just doesn't move me.

So, how do i get the midrange bloomy sound of the SP6b with more detail and better imaging?  Folks on this thread mentioned above:

1. Mapletree Audio Design Ultra 4c 
2. a Don Sachs preamp--not sure which
3. Atma-sphere MP-3

Would one of those would fit the bill?  My budget is $2k (notice the creep from my original post.)  

The other alternative is to overhaul the SP6b--I suppose new wire and caps might brighten it up, although i don't know if that means more detail and better imaging.  Also, i'm not sure who could do it, and I'm not sure that i want to do violence to a vintage piece of equipment.

Please bear in mind that i've done some reading, and a little listening, since my original post, but i'm still very much new at this thing.  You're hearing my subjective listening experience.  Apologies in advance if i have maligned a piece of equipment that you hold dear.  Folks have been very generous with their time and advice which i really appreciate; some have been grumpy when i don't respond right away--please understand that life circumstances prevent me from being tethered 24/7.  Thanks so much for any thoughts.

G'day Robert,

If you are lucky enough to find a Vincent SA-T8 then this will give you what you are after. Massive step up over an AR SP-6 & AI L3. Fully balanced all tube design, has massive soundstage depth & width & oozes musicality in spades. Just has that "just right" midrange "warmth" and has none of the dry, etched, overly analytical presentation that plagues many Pre-Amps, which you are trying to avoid.

Replace the "crap" stock tubes with Psvane's and you will have a Pre that competes with or betters many Pre's costing multiples of it's cost.

Hope you can find one.