DACs, any experiences?

I´ve bought a DAC really just to test it out, I bought the Fiio E17 and uses a pair of Sennheiser 280 HDPro headphones to test it out on a iMac, but honestly I cant tell the difference.
I´ve tried to google a little, and some said it needed to "play in" for about 48hours, but how could that be? Its electronics, its not a speaker element.

It also is a headphone amp, but I really have no trouble using the headphones in neither the mac or phone, so I cant find a reason to connect it to the phone, except if it makes so that the phone doesnt drain battery as fast, but then its an expensive battery!

I´d rather wait for iPhone 28 or something with its endless batterylife.

Any reason to keep the Fiio E17 or just return it?

I'm not sure I buy that "play in" claim either.


If you honestly can't tell the difference, I guess there isn't really a point.

I know that I can hear a difference between my macbook's audio card and my interface's better headphone amp. And my 2g ipod touch does not even compare when I try to use my good headphones with it (too high impedance).
So it should make a difference, but if you can't hear it, no sense in trying to convince yourself (or letting others convince you) that it does.

...the difference comes when you're monitoring a work in progress.....

on finished mixes it's hard to tell....

but when you start from scratch you get better results in the end.....

but a real audio interface with some multiple in's and out's iAND a headphone amp is the better investment.....

After some googling, it seems most Macs have pretty good DAC´s built in, so it might be the reason the difference isn´t there, and my phone´s amp is strong enough to drive my headphones so I have no reason to keep the E17, returning it today, the money is better spent on something else.