Basic Preamp - suggestions?

Awesome. I will look into those Adcoms. How are NAD preamps?

Do people have opinions on whether buying a dedicated preamp is better than just using a decent receiver as a preamp?

My setup is

Linn Espek speakers
Oppo 970HD (cd transport)
Rega P2 turntable
Rotel RB 1050

You asked for used, but if not absolutely opposed to new, the Maverick Audio tube DAC /Preamp /headphone amp might be just the ticket. It's $200 and you could roll to a better tube later down the road ... like a GE 5-star 5670. With your set-up, you can go digital-in with the Oppo, put a basic Pro-ject pre between the Maverick/Rega and you're in business without dropping a whole lot a coin in the process. In addition to headphone amp, the Maverick D1 even has line-in for iPod. I have this great little "Swiss Army knife" component anchoring my office system.

I would look for a PS Audio 4.5 or 4.6 preamp. It is passive or active has an excellent phono stage that can handle LO moving coils and it's pretty versitale and has an outboard power supply that's twice the weight of the preamp. Even the PS IVH is still a pretty good unit and
is easily found under $200. There are several hafler units out there DH100 or DH101 but the PS still has a better top end than the Haflers. Good Luck

I noticed you have a Rotel amp. I have a Rotel preamp that used to drive a Rotel RB1080 and I was very happy with it. Might want to consider the RC1070 pre. I have since upgraded the amp to a tube amp and I am now in the process of upgrading my pre to a much more expensive tubed pre, so don't take my moving away from the RC1070 as a bad sign. I think the RC1070 is a very good unit.

I have not heard the Maverick that Strateahed suggests, but sounds interesting.

The amp/preamp interaction should be quite important. You might want to check with the Rotel forum at HTGuide and see what people are using. Keep in mind many there are Rotel fundamentalists, though...

Good luck!

My friend has B&K gear. The preamp is a CS-117 model wih built in phono section; not sure on the amp model. He runs Paradigm Monitor 9s and has a Pro-ject Debut III table. He acquired the B&K preamp for around $170 used. For money spent it the best system I've heard.
So, check out B&K gear. I prefer tube gear but must admit the B&K gear sounds much more musical than my older NAD or Aragon gear. A great bang for the buck.
prior to that had had a small preamp - Superphon I think.
That also sounded darn nice for the money.
rpeH
Good luck