Hi, I'm planning to purchase a pair of Sennheiser PX100 headphones for
use with an Ipod and I'm not certain if I need to concern myself with
the purchase of a headphone amp.

Eventually I plan to use the "Line Out" section of the iPod...but for
now I will use the Headphone jack.

1 - What benefit will I gain using the amp and the Senn's in either
Line Out or headphone jack?

2 - Is the amp intended to be used with larger units?

cheers,

Richard