Case in point: the Koss PortaPro headphones first hit the market in 1984 and have become such a favorite with audiophiles that the company leaves the design (and the price tag) untouched. You can still pick one up for less than $50, and they come with a lifetime warranty, no receipt necessary. Check out our favorite budget headphones for more selections.
The iPhone will drive the headphone fine and make a very nice sound, but the amp will make a big improvement in harmonic extension and soundstage. Use the amp whenever possible. Both Headfonia and I concur that the E07k is a great amp, and probably the best thing you can get for up to twice the price. I’m familiar only with the E07k, the E17, and the E12. I think the E07k beats the E17 (and both are also USB DACs), while the E12 is just an amp, and has a darker sound but with more power for inefficient headphones. The Philips is not inefficient.
A planar magnetic driver consists of a relatively large membrane that contains an embedded wire pattern. This membrane is suspended between two sets of permanent, oppositely aligned, magnets. A current passed through the wires embedded in the membrane produces a magnetic field that reacts with the field of the permanent magnets to induce movement in the membrane, which produces sound.
I will get to these today. Just imagine the sound you hear is a line stretching left to right, with bass at the left and treble to the right. Now the line is tilted toward the right so the bass is higher (stronger) and the treble lower (weaker). That’s an example of getting darker. It’s not a perfect analogy, since any complex combination of sounds or balance is possible, but in general when something sounds darker you’ll have less influence of the treble.
Recently released this summer, the Headphones 700 are the best wireless over-ear headphones that Bose has to over. The combine the best-in-class noise-cancellation with great audio quality. Other than the design overhaul, the biggest difference from the QuietComfort 35 II is that the Headphones 700 have a significantly upgraded microphone array. This allows the headphones to have a wonderful tranparancy mode (or ambient listening mode), and makes maybe the best headphones you can buy for call quality.

This is better than I thought it would be. Worst case is the T51p won’t have the excitement of the more “V”-shaped headphone sounds, but you’ll hear more of what’s actually in the recording. The more neutral headphones are most often a little bright (that’s what most users say), and can irritate on electronic and improvised music, but the T51p didn’t show any of that with these 3 tracks.
Once you’ve got that all order, to put a cherry on top it would be ideal for the amp to play nice with my laptops (PC at work, Mac at home) *and* my *iPhone* 4S.  I haven’t found a headunit that works with PCs and iDevices.  If one doesn’t exist it would be a big plus for the amp to include inputs so I can get digital sound out of my iPhone (with the Pure i20 or its ilk) and into my headphones.
Choosing the right headphones makes it possible for you to hear your music the way the artist who made it intended, with all the nuances from the right bass and treble levels so you can hear every drum beat and guitar strum. Not all headphones are ideal for everybody and are a matter of personal taste, comfort and style. Find the ideal pair of headphones to use with your mobile device, stereo or computer, available at our Every Day Low Prices, and get your groove on.