a research or krell pre amp for krell ksa-150 amp?

i am looking to buy a pre amp for my krell KSA-150. i have been planning on buying a krell used in the $800.00 price range. i noticed AR were signifigantly less expensive and from what i have read, seem to pair well with krell amps. is there a pre amp that is known for this combo? i listen to all kinds of music from jazz,R&B to rock. i definately need slam but i also want warmth and detail. what is the best way to accomplish this?

please advise
I have Krell ksa-250 and use a Bent audio passive (transformer volume control) as pre. You would have to spend big $$$ to do better. Has rca/xlr in and out and runs about $1200 new from bentaudio.com, they will let you try one if you want. The guy to talk to is John Chapman and he's a great guy. My Krell is great with this unit, huge soundstage, great slam and midrange to die for.
First of all, the KSA150 is several generations old. The improvements that have been made by Krell are not small. First was the "S" series which was much sweeter with all the slam of the 150 and more control. Then came the FPB series which blows away even the S series, especially on the mid/highs.

The difference with preamps, in my opinion will not be as great. Of all the Krell preamps that I have had (and I've had a few), the KBL was the best bang for the buck. You can get them used for $1200 + or -. (By the way, I now use the KRC-HR with two Krell amps)

Drrdiamond, so what are you trying to say, his ksa-150 is an old piece of crap. He asked about a pre to use with his ksa-150 and you tell him all the newer krells just blow the doors off his. For one thing that is not true at all, as a matter of fact the old ksa-150 sounds much better than many a krell that came after it. As a matter of fact, most of the reason that krell got a bad rep. for being brite and lifeless came from the amps that came after his ksa-150. The new krell line sound very good and its about time because none of the krells made between the ksa-150 and the new line will smoke his.
Drrdiamond, when i become more wealthy...i will buy a new one. till then i have to make this one sound good.

Just to explain my self on MY opinion:

When I was upgrading from my KST100, I compared the KSA150 to the KSA250. My vote went to the 250, not for the power, but that it sounded less grainy. At the time, I was using one amp to drive double Cello Amatis. I later changed to the B&W800's.

It was on the B&W800's that I personally compared the KSA250 to the KSA300S to the FPB300.

With the aid of the Krell KBX active x-over, I now use the KSA300S for my bass and the FPB300 for the mid/highs on my actively biamped B&W800's.

I am not suggesting that "drum" should scrap his amp, but I would suggest not spending large amounts of money on the preamp, because the improvement would be more significant if spent on the amp.