Can anybody tell me if the headphone output jack on an iphone is a good quality source to connect to an amplifier? I don't own an iphone but would like to get one if its a good quality source.

What would be a good upgrade from these cans that still have a similar amount of bass?

I currently have a  asus xonar essence st and a pair or ultrasone pro 900's, What kind of headphone amp would be the next step up that would offer a significant upgrade from what i currently use? I don't really have a budget but how much would i be likley to need to spend to notice a significant...

Will using a 1/4 inch jack to 3.5mm  smaller jack along with a 3 meter exsention cable effect the SQ of my ultrasone pro 900's? The stock cable is one of thoose spiral round ones and keeps getting tangled up which is pretty anoying.

Hi everyone   Ive been browsing on here for a little while which deciding what headphones to buy, I knew pretty much nothing at all about headphones a couple of weeks ago, i have been into car audio for a while and have built a few big bass heavy systems 6000 watt rms rms on the subs tuned...