Preamp pairing with B&K ST-140

Hello all:
I'm ending my mid-fi ways and entering the hi-fi entry level realm. I was recently blessed with a B&K ST-140 and I'm using it with a Newcastle R-925's pre-amp out. Sounds good, but I'm told if I upgrade the preamp I'll give the Newcastle away. I split time between a pair of Paradigm Studio 40's and Klipsch Forte's. The ST-140 will hang for a lil' while but I foresee replacing it in about a year???
Any input appreciated,
My local guru at Wilson's audio highly recommends ARC. He has a SP-7, recently serviced, but the $800 tag may be a little steep right now. I do want to minimize swapping components, as I can see you can spend more $ if you don't hit the right price point.
No oil in my morning coffee... yet,
Walter in New Orleans
I'm learning and was recently exposed to this. So you should match a preamp with relatively low output impedance with the SS's low input. Any rules of thumb to go by on this, like ratio's or either not to exceed?

I must admit, It sounds really damm good thru the Newcastle's pre, especially hooked to the Forte's (Many HiFi's shun them). Not harsh, great mid's. Percussion is repro'd very life-like. Sounds like there's a drum set in the living room. And the bass must have been canned and shipped in.
Hi T-kid,

FWIW, I owned an ST140 for many years and mated it with several different preamps from a dyna PAS 2 and PAS 3, Luxman, Acoustat TNP, and a Music Reference RM5 mkII. All sounded great with the St140. The St140 was always considered a "giant killer" and is a great sounding very tubelike sounding amp.

With the Klipsch Forte's, I wouldn't worry too much about any impedence mismatch with a tube preamp, and being in this hobby for over 25 years, I totally disagree with Rrog's and Upstateaudio's remarks. From reading their remarks, it sounds like they've never tried their B&K with any other preamps other than B&K; however, I have and with great sucess too.

I would not recommend an ARC SP7 as the SP7 was SS, and ARC's solid state preamps were nothing compared to their tube units. Also, at $800, you could do far better than an SP7. Please let us know your budget so you can be better advised,
Tabascokid, I disagree with Lou_setriodes. Keep in mind some people have better taste than others and all preamps mentioned by Lou-setriodes are mediocre at best. Also, his comment regarding your Klipsch speakers and mismatched impedance with a tube preamp makes no sense at all and I doubt he has ever owned an Audio Research preamp in his life.

You can't go wrong with the same brand amp and preamp. You will hear a rightness to the sound with like brands.