best budget pre used

Hi all...

i'm looking for advice on which pre might sound best w/my setup consisting of:

b&k st-140 > maggie MMG / mirage sfx-8 sub

I plan (eventualy) on getting a benchmark DAC-1 as my front end and bypassing a preamp entirely, but I need something to get me through for a while. anything at all will be an upgrade from what i'm coming off of.

so, anything in the sub $300 range will do. I see plenty of cheap rotels going for under $150, but i have to wonder.

thoughts?
would a b&k pre be best suited to the ST-140?
a tube pre? I'm eyeing a few within my pricre range. I love the tube sound, but I hear this ST-140 is warm sounding on its own and would rather have something clean and clear ahead of it.

thanks...
I apprecaite all of the great advice given to me over the last month or so.