Audible Illusions Modulus 3 is one of the best. They can usually be had for well under 1K. There's also the 3A, but some listeners like the original 3 better, probably because the circuit is simpler. I had one for some time and the only reason I don't have one again is because I've gone to a Klyne. Klyne's are usually going to show up rarely and outside of your budget, although with patience, you may be able to score something like an older SK4 or 5. You'll be hard pressed to find a better pnono section than a Klyne.