I purchased a used DX-1 and a used Gamma DAC around the same time earlier this year--the DX-1 to replace a failing CAL Icon and the Gamma to "warm up" a Philips CDR unit, which it has done beautifully. I've since given away the DX-1 as I replaced it with a CAL Delta/Alpha combo playing thru a Jolida 302B integrated tube amp (beautiful). In the meantime, I had a month or so to A-B the DX-1 vs the Philips with the Gamma DAC. The Philips CDR unit is pretty basic sounding on its own, but the Gamma makes listening to CDs a pleasure as I copy from them. To make a long story shorter, I believe the onboard DX-1 DAC is identical (or nearly so) to the Gamma. Nevertheless, I preferred listening to the otherwise lousy Philips driving the Gamma marginally more than I enjoyed listening to the DX-1. It is a little smoother sounding yet has slightly more presence , imho.