Since the EP9ES is dolby digital, NOT DTS, I would look for something that supports DTS is the same price range. I can think of a few choices offhand..
You should be able to find a used Marantz AV-560 in your price range that supports both DD and DTS, if you don't want DTS, a AV-550 or AV-600 should fit the bill as well.
You might also want to consider a Sherwood/Newcastle AVP-9080, I've seen them used for around $500.00.
The Harman Kardon Signature 2.0 can also be found for around $400-500 used.
You might also think about a Millinum DTS decoder ($200 used) paired with a Fosgate 3A, a Rotel RSP-960 or 970 or a similar preamp that can be had for around the $300.00 used mark.
Hope this helps..
Mark