What is the best used sub-$500 DAC?

I heartily recommend the Oritek-modded Zhalou at this price point. It's sins are mostly of omission (and it has very few, for this price). Gives up a little extension, dynamics and life compared to pricier models, but hangs with much more expensive pieces. It replaced a Modwright P3A and Consonance 120 in my system.

Thanks for all the responses. i'm usng a trends audio class t (TA 10.1) amplifier and a pair of tekton design 6 inch fostex full range speakers and plan to replace the amp with something low powered and single-ended. what about the venerable CAL Sigma? is it competitive anymore? thanks again for all the options...just what i needed.

Nhtran: How would you compare the sound of three units you mentioned? I am very curious, thanks.

EAD DSP 7000 sIII

A friend had the CAL sigma long time ago, without a jitter box it was not good.

Don't forget about modded Art DI/O's, which can be had for a song these days. Still a very competative DAC. Lots of detail and resolution and dynamics and very musical. Able to handle soft, sweet stuff and complex music with ease.

It is NOT an overly soft NOS sound, so if that is what you are looking for then look elsewhere, but I've found that NOS DAC's generally can't handle anything with punch or big dynamics or that is complex.

Enjoy,
Bob