Do you mean amps of any kind including the integrated amplifiers used in computers? Because I notice that even the max volume of my Thinkpad T510 is just barely able to drive these. The sound is flat, the clipping is apparent, and its not really all that usable. It is *much* better on the 2011 15" Macbook Pro I also have, but I definitely feel it could be better. I figured I would kill two birds with one stone and get a better DAC along with a much better amp for these and eventually my future headphones (Considering Sony XB1000 for dubstep music and Beyerdynamic DT990 600 ohm headphones for some of my orchestral music due to the highs being a little too harsh on my 900s (and muddy on the XB1000s)). I also still have my reshelled Super.fi 5 EBs but I don't think they honestly need any sort of amping. They can already get as loud as I can comfortably handle iwth "boom" to spare. It would be nice if the same amp could handle a JH13 though in the future.
I know its hard to have a "one amp fits all" approach same as with headphones but I'd hate to buy a basic amp only to have to upgrade when I bring others into the fold.