Best phono pre in the 500.00 price range Used

The the $500 range used, it's hard to beat a Conrad Johnson PV10 with included phono stage (or, for a bit more, a PV9A). Use it as a full function preamp or just use it tape out for a phono stage only.
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One vote: Dynavector P-75 for noticeably less than $500 and the rest on LPs. From personal experience, the P-75 works well with the OC-9. Good listening!

Hi- I've had the CJ PV 10 for about a year, you can see my related gear. I added about $150- to the $500- purchase by adding Telefunken output tubes on the analog side, which are noticably different than the CJ tube set. I like them, find them to be a bit more revealing/extended, fresher tone but that is subjective, you may find them different. Very straight forward well designed pre that adds just the right amount of tube to KAB/TECH tt/Bryston/Alon gear I have. The biggest drawback to me is that it's gold/alum faceplate doesn't go with anything. Once past that the good things start to add up in a hurry, starting with the sound. Some like the SS/Tube sound, some don't. I find it to be accurate at the bass end to pretty good mids (where the tubes shine) with the upper frequencies covered in spades. No listener fatigue at all, in fact quite the opposite. You might just have a very sweet sound from the Classe/ Cj/ B&W along with a very nice analog set up. The Conrad Johnson PV10's are also very liquid, if you decided to sell it you would probably get back your investment fairly quickly. Should be able to find a clean one for $500-. Good Luck and good listening.
Zen

I second the P75 - it is a very fast detailed phono for the price.

Pick up a used Audio Research LS3 pre amp. This is a great inexpensive pre and it can be had for 500-600 dollars.

Etbaby: The Audio Research LS-3 is a line stage and does not contain a phono stage.