ATM am on either an Essence ST or a basic CD player from Philips. I don't want to buy a DAC, so am planning on buying a good CDP (Denon 710 / CA 650C), also because I keep my headphone rig in the bedroom - no space for a DAC. The only reason I haven't gone out and bought one of these CDPs is I'm totally divided on the reviews. The CA will make a better complement to my speaker rig, while the Denon CDP has a headphone out, which can be useful, it also has a newer DAC.
Amping is not required for the these cans, but I use my LD Micro Tube - finally. Upgrading that is also due, WA6SE most likely, because I need the two outputs. But I need to save up. ATM, on my current setup, I do not notice much of a difference between both versions of the Grado - more like a subtle tonal shift in the mid-range, and slightly extended highs, but that could be pre-burn in brightness...only 10 hours on the RS1i ATM.
Denons (D7000) are also in the mix of things, as is the AT A900 and SR225. But I am not getting time to listen to music on my HPs which is pissing off...only speakers ATM.