I suggest an audition of the PS Audio Perfect Wave Transport and DAC. It offers multiple choices of sampling and filters. The setting that is most pleasing is 44.1,and auto filter setting. I have spent hours listening to this and there is no fatigue. I'm not a gear type guy, and the only reason I parted with my Theta Separates was that the new company owners wouldn't repair them. Auditioned players that I couldn't afford such as AR CD 8, The Ayre DAC server, Meridian, Marantz, and they all sounded pleasant, but not better. A friendly suggestion to try the PS Audio gear a try. I think you'll get off the upgrade path, and see how good your system really is.