Amps ARE NOT always the answer!Don't get me wrong, I'm a big fan of headphone amps. But I think it's interesting that even people who claim to consider themselves "audio purists" (high end "audiophiles, or whatever term they may choose) largely insist that an amplifier is ALWAYS better. It isn't! Amplifiers, like any other piece of gear placed in a signal chain, CHANGE THE SIGNAL! The TRUE purist approach is to have as few doo-dads in the signal path as you can get by with (as can get the job done!). If you have an extremely sensitive headphone which is delivering signals at a volume level high enough for you, with peaks that are completely "un-clipped", then an amplifier IS NOT necessary!
I think even Tyll from Headroom will admit that even the best amplifiers (and Headrooms are certainly among the best...in many respects THE best) change the signal passing through them in some way. NO amplifier is the proverbial "straight wire with gain".
Now I'm a radio production "wiz". I'm certainly not against using compression, limiting, equalization, WHATEVER during the creative process to achieve the sound that I'm after. But once that sound has been achieved, I'd prefer that it not be randomly changed by passing through unnecessarily long signal chains, with pieces of gear in the signal path that simply aren't necessary....like a headphone amp connected between a device which already has plenty of output to drive 'phones, and extremely sensitive 'phones such as many of the more popular models from Sony, Grado, Koss, etc. Of course, I consider my work to be a "finished product", so if I were king graphic equalizers, tone controls, etc. would be outlawed as well! But that's a topic for another thread, in another place.
I love my Total Airhead, but find it unnecessary when using my Sony MDR-7506 with my cd, md, or fm portables. But when I want to plug my HD-580s into my portable, OF COURSE I plug in the old Total Airhead! (Contradicting myself just a bit, I DO prefer the KSC-35 when driven through the Total Airhead! It just has more "oomph".)