Quote:
Originally Posted by
Electrophile 
I just got a pair of dt770 premium 250 ohm from ebay today. The headphone was listed as new open box item. I briefly listened to it and found that they produce similar volume as my Akg 702s do when either plugged straight into my laptop or amp. Plus...when set on high gain, my UHA3 is able to drive it to comfortable volume with the volume nob only at 10 o'clock....
Does this mean I actually got a 32 ohm version??? I have no multimeter to test it nor could I find it written anywhere on my headphones, apart from being listed as 250 ohm on the box... I have 6 days left to return it and get refunded!
Could anyone give me some suggestions? Thank you.
I'd also appreciate if I can hear some comparisons between the dt770 premium 32, 250 and 600 ohm versions. I know the 600 ohm version is considered more neutral. But by how much? And are the other two version considerably worse than the 600 ohm?
You probably really have a 250 Ohm headphone. The reason why it is not quieter than the AKG is that it has better sensitivity, which negates the impedance difference. Basically, for every doubling of the impedance, you need +3 dB of sensitivity to keep the same loudness, assuming that the output impedance of the source is negligible compared to that of the headphones - if not, then it works in the favor of the higher impedance one. Although the following graphs do not seem to represent the frequency responses accurately, I assume they got at least the overall sound pressure levels more or less right (note: the DT770 is the Pro version, but it is probably not very different from the Premium):
It is a common myth that lower/higher impedance by itself guarantees that less/more amplification is needed, or that the headphone is easier/harder to drive.
Regarding the comparison of various impedance versions, I recommend reading this thread.
Edited by stv014 - 11/22/11 at 2:50am
