I checked out the edcor link. $49.98US
The ignorant neandertol in me wants to ask how far towards the high end do the specs they quote fall?
Total Harmonic Distortion (THD): Distortion is less than 0.05% (midband) at full rated output.
Frequency Response: 20~20k Hz, ± 0.25 dB.
THD less than 0.1% is believed to be inaudible. The (claimed) frequency response is excellent too, even most high-end amps don't get as close to ideal.
In other words, the specs say you should spend a lot more than $49.98US on headphones to match its quality...
Borislav