Best Pre-amp for $500??

I would choose a Dynaco PAS 4 preamp with phono stage. Great preamp!

I would go with George suggestion and get a 5-6 year old $3,000 avr that they are selling for nothing because it has no HDMI instead of paying a ridiculous 70%-80% of new price for a unit that had a 70% mark up to begin with

There are at least 5 processors close to your price range like that listed here right now. They have same or much better DACs or twice as many DACs than used stereo pres that people want 5-10 times as much for. Plus you could use them for audiophile audio in 3-4 rooms at the same time with amps. Or just run hdmi to your tv and digital out back to receiver and you have everything the new models have and more.  lis758ec    lis761c4    lis75623  

In the theme of dinasty, the Parasound AVC-2500.  Does everything you're asking for.  Originally $3500.00, used $400ish, maybe even less.  You didn't specify what digital in's you needed.  The AVC-2500 does not have hdmi, but it does have optical, coax and, of course analog.  It's for home theater setups, so it has bass management plus some other eq functions. 

This Grant Fidelity DAC-11 can be configured to work as a preamp, input capability, versatile little DACs and you can play with tubes   - inputs-  2 sets RCA, 1 coaxial, 1 optical and 1 USB-, no remote. http://shop.grantfidelity.com/Grant-Fidelity-TubeDAC-11-D-A-Converter.html

I still like the Classe option, having used one for a while and plenty of others, tough to beat for the money. That and a Sim Audio D100 could be swung for around $700.