Just in case any one interested in the freq. resp., I generated one of my own.
Go-vibes USB DAC is the baseline, compare to Practical Devices XM3, Travagans Colors (dogbone), and FiiO E3 of course.

Also want to add that
FiiO E5 is currently under development, and will have the below features:
* Independent On/Off switch
* Electronic volume control to eliminate hissing after long usage
* Back clip
* Build-in rechargeable Li-ion battery
* USB charging circuit
New functions include:
* Output power increases 30%
* Better SNR
* Less distortion
* Better resistance to electromagnetic interference
E5 will be roughly the same size as E3, but slimmer.
No release date yet.
This post has been edited by ClieOS: Sep 11 2008, 10:04 AM