Matching Preamp for Rotel 990BX and Snell E III

I am using a Rotel 990BX power amp with Snell E III speakers. My current preamp is a B+K Pro5 preamp. I'd like to spend no more than $750 on a preamp to upgrade from the B+K Pro5. I worry about pairing many of the preamps at that price point (e.g. older Threshold) with the amp and speakers. I've never been an Adcom fan (though, admittedly, I've not listened in 10 years). I need a phono input.

I would be grateful for any advice. It's not easy being a teacher and enjoying audiophile gear!

Thanks,

Matt