Just my 5 pennies. I had a DNA-500 too and it was a super amp. I started off of with a LAT Internationa AC-2 MKI and was very, very happy with it. It really 'lit' the amp up to my ears. The great thing about the LAT cable is, it's inexpensive and you can test drive it for 45 days. All you loose is shipping costs (marginal).
http://www.latinternational.com/index.php/product/ac-2%20mk%20ii%20%20new%21.html
You could do alot worse.
http://www.latinternational.com/index.php/product/ac-2%20mk%20ii%20%20new%21.html
You could do alot worse.