I'm so glad to find this post! My DV-50 has been in the house about three weeks and it still never misses a chance to make me break out in grins...
I'm using the Audioquest Panther RCAs and they seem very well-suited. Admittedly, my player is still "breaking in" somewhat...
The RDOT / FIR filters are still being auditioned, although I agree with another post on this thread: at times, the RDOT+FIR will sound a bit "hashy" with a bad CD (those "relics" from the 80s...). But for almost everything else, I've left the RDOT+FIR filter combo in place. It seems to give the music "heft"...in a good way.
I haven't tried grounding the player to the amp yet. Has anyone ?????
I have to admit, I'm a big fan of this player, but it has one major flaw.. The DV-50 will expose any improvement, as well as any detriment, you bring to the system... For instance, (and I know this isn't REALLY a problem, but bear with me): put a better cable in the signal path and the sound jumps up quite a bit.. you begin to get that nagging "audio-enthusiast" question banging around in your head, "well, maybe if I add this ONE MORE BYBEE FILTER...". I can't remember wanting to tweak my system like I have since the DV-50 showed up.. you just want to put it in the best environment... it seems so "up to the task"...