@OP Carlyleciv - To answer your question about preamps in simple terms: the preamp is the part of the amplification chain that takes the input signals, allows switching between them and volume control, and passes the signal to the power amp, which is the part of the amp that creates enough power to drive speakers. Those two parts can be separated - pre/power, or integrated. Many integrated amps include a phono stage. This is required for vinyl playback because the output of a cartridge is lowere than that of a CD player and phono also requires specific frequency equalisation because of the way records are cut compared to CD.
Your one K budget is tight, but you can get a decent integrated amp like a Rotel A8 for under five hundred dollars. It's a properly engineered amplifier that sounds good. As a few posters have said above, the Kef LS 50 is an outstanding speaker though it really needs a more expensive amp to drive it. But if you could find a used pair they would still be a good buy. Buying new, you can get something like a Wharfdale Diamond, along with the Rotel for within your budget and have money left for some decent speaker cables.
If you can sell on your existing speakers, the next priority would be speaker stands, followed by an upgrade for the Rega Carbon cartridge.
I used to sell a lot of these type of entry level systems back in the eighties, but the recipe of a Rega with a decent integrated amp and a pair of stand mounted bookshelf speakers still hasn't changed, both to deliver good sound in itself and as the first stepping stone on the path to even better sound.