Thinking of buying a pair of Splendor D7.2...

Very tough question gearhead. In fact, I disqualify myself from answering it. My tube preamps consisted of the long-discontinued Audioprism Mantissa and the almost current ARC Ref 6. 
Do yourself a huge favor and call Galen Carol. He will not steer you in the wrong direction. 
A hidden gem is the Schiit tubed preamp though. To me, figuring out the volume control is half the battle with a preamp and the Schiit design does that. But-Galen Carol will say-truthfully-he can not comment on 
Schiit since it is sold factory-direct. 

I might suggest a used Audio Research DSI200, which can be found in your price range.
It’s what I use to drive my Spendor D7’s.
It’s solid state, class D, but doesn’t use off the shelf modules like most class D today. ARC designed the circuits to sound like their tube amps. Runs cool to the touch and can be left on all the time with min current draw. I am very happy with the combination.

I am reviving this thread to comment upon this surprise-who would believe that the Spendor D7.2's could sound great with 8 watts? I had a feeling they would play loud enough for my smallish room but had no idea they would sound as good as they do. The Ampersound Nautilus may only measure at 8 watts but all that iron it employs evidently puts out some grunt that does not measure as watts. The sound is the most halographic and true to texture and tone that I have ever achieved at home. There is always a trade-off and in this case the deep bass is not tight. It is not bloated either, it is just soft, not as extended as it can be, and even a bit muted based upon playing albums and cuts I know better than my own wife of many years. But the pleasure factor is off the charts. Ever since getting my Nautilus delivered three months ago my ARC Ref 150 SE has sat gathering dust. I have no intent to sell it. I love the ARC amp. But the Nautilus is simply too pleasing for me to give up yet. Perhaps if we have a cold winter the ARC with it's eight KT150's will go back in for the sake of warming up my listening room.