Hello everyone, I'm new on the board, and wanted to find out some more info on portable, or wired head/earphone amps. How necessary they are, and how much they really clean up the signal/sound.

I've had a pair of Etymotic ER*4P's for the past 2 years, and have always just listened to them by plugging into my mac, or my iPod for tunes.

Any help towards articles or other posts would be greatly appreciated.

Marc