I think "the best phono stage under $500" is a used preamp with built-in phono section. If you go with one less than 10 years old, then you won't have to re-cap it. Items like the Counterpoint preamps and the MFA preamps and even maybe some of the Audible Illusions earlier models may be available in that price range. If you don't mind re-capping, then you can go back to some early ARC preamps like the SP-6, or the Precision Fidelity C-7, or even some SS preamps with phono stages. Just use the "Tape Out" and run it into a "Line In" on your existing preamp, and this will bypass the volume controls and other unwanted circuitry in it, prior to entering your main preamp.
New $500 "best" phono stage?
A friend said he recently read an article by Mickey Fremmer in which Fremmer said a $500 phono stage was among the best he's ever heard. But my friend couldn't recall the name of the phono stage. Anyone know what my friend is referring to? As a Plinius Jarrah owner, I had figured I'd have to spend 4 times the cost of the Jarrah (about $650) to hear something better. So a "best" $500 phono stage could be very appealing. Thanks, everyone, for your assistance.