I read that those expensive headphone amps have very low impedances so that it can have higher damping factor for supposely better sq. Googling around gave me some infos like ipod's output impedance to be 5ohm. I read that as general rule load impedance should be 10 times more than the source impedance so that the amp have better control of the drivers. What I can conclude is that other than amplifying the sound to suitable listening volume, the amp can provide lower output impedances to improve sound quality especially on lower impedance earphones/headphones, is this correct?

What's the impedance output of the Fiio E5? Does the impedance output of this amp affected by the input impedance(since E5 have preamp and opamp inside)?

Just got my E5 too, I'm using it's bass boost with my hippo shroom.

If you have iphones or ipod that supports LOD then E1 is better. Otherwise E5 if the general amp to use.

if you use the normal mode, you will lose the bass that's below 100Hz. it's as much as -1dB at 30Hz
I'm using Eterna without the E5 now.

Of course the volume controls on ipod cannot be used with E1, it's because E1 takes the line-out signal from ipod instead of headphone out. Main reason for using E1 is to get cleaner signals from line-out and/or driving harder to drive headphones/earphones which will sound sucky if plugged directly to the headphone out.

Any news on Fiio E7 when it's going to be in and the price?