Originally Posted by bunnyfluffy
I just checked their page, and the E17 actually says 150 ohm. That's weird, cuz I've seen 300 ohm written in on retailer websites.
I am interested in why they're fine amp wise, and why they would be conservative, if you have the time to explain it. Thank you.
Fiio used to say the E17 was able to drive 300Ohm. They changed that when the E18 came out because E17 and E18, while they can get pretty loud volumes with 300 Ohm headphones, they might be slightly in the limit regarding the current.
This is just my opinion but, while both might be in the limit to drive them properly, we are talking about a portable device, which means that the DAC part is going to be the one providing the of sound. In other words, if your computer has a crappy DAC, it doesn't matter if the headphones are properly driven because they are going to still sound like crap. Now, if you add the DAC in the equation, it doesn't matter if the headphones are slightly underpowered because the sound is going to be good (not perfect but much much better). That's why if you are thinking in mostly portable use you should go the Amp/DAC combo way.
E12 is more meant for orthodynamic headphones, and I highly doubt the HD650 are really that much underpowered (if any) on a E17 or E18. Even more, the difficulty of being driven doesn't relate with the impedance. For example, HE-500 or Q701 are difficult to drive, and the impedance is fairly low (less than 100 Ohm).Edited by Ashade - 1/2/14 at 10:19pm