Ok so to summarize. Provided a good source, an amp would only allow me to listen louder without experiencing clipping, and with no "noise" when there's no music to listen to. And by louder I don't mean CRAZY loud, but just loud enough to listen to music with headphones with high impedance...

Listening to a 320kbps mp3 with my iPhone, I would benefit from a DAC ? The iphone's analog output is considered poor ?

Nononono sorry, I can push it beyond it's limits (what you call clipping?) with my CMoy/source at full. I was talking about just the iPhone without the amp.

Thanks :) I do find that my iPhone isn't loud enough with my DT770 compared to my SR80's...

Hello Head-fiers !   I've been reading this forum for quite some time now, but I'm not too much of a poster ....  Thanks to you guys, I've bought my first real headphones, Grado SR 80, then bought the HD 414 pads, cause 1/ they look awesome, 2/ I didn't like the original pads. Then...