Originally Posted by nickchen
I personally find that your-can-doesn't-sound-right-because-your-amp sucks approach a bit questionable
It depends. If you're clipping the amplifier you're going to have distortion.
Honestly, do I believe a K701 needs to be amped? Maybe for volume, or if you want to add a tube sound to it . . . but on its own it's a relative simple load across all frequencies with no huge jumps to strain an amp.
On the other hand, the K601 is less efficient, and has a large peak in impedance needing at least an amp capable of powering a 250ohm load to not clip.
Then you get to Senns. They often pop into 600-650ohm territory. Once again . . . a very infamous load to drive.
Then Grado, Audio Technica, and some others offer comparatively easy loads to all of the above. They are efficient and tend not to cause amplifier clipping from any decent device.
The question is . . . how much amplifier do you need? Well consider that you can get 101dB at 1mw out of the K601 and 105dB out of the K701. These level are enough to kill your hearing as is, but some scream for dynamic range.
Look at these impedance plots:
As we can see . . . these may be harder loads for a simple MP3 player, etc. However I often hear "portable/cheap amps can't work", and to those I say: bollocks.
The Mini^3 HP edition can put out 300mW into a 33ohm load, and 30 into a 330ohm load. This means more than sufficient volume to kill your hearing and absolutely no clipping or distortion. Combine this with the solid RMAA results and there's no reason it's not capable of driving either phone.
Just to show that it doesn't take an expensive amp to make these headphone work properly. If we were talking Sennheiser on the other hand . . .
So for those considering these phones . . . make sure you can drive them properly. If you can and you still don't like them then sell them off unless you want to try using tubes to fix them . . . which if you must "fix" a headphone than there's already an issue.