Line out is in the dock connector pins. Headphone out is on the 3.5mm jack. The headphone output has gone through the headphone amp internal to the ipod.
I won't bother to argue which is better, or sounds better. But they are different.
There is a product called "PocketDock Line Out" that will give you 3.5mm access to the line out for a comparison. I can tell you from experience that the sound improvement is a trade off.
The SNR on the headphone out may be better in some cases because you can crank up the volume before the signal leaves the iPod. With good cables in a good environment eliminating the noise from the iPod's internal amp may produce better sound. Cranking up the volume also takes a toll on the battery life unless you are charging the iPod at the same time.
I personally like using the line out unless I am using headphones. The line out "volume" does not change with the iPod's touch wheel volume. Once the receiving device is set there are no "volume" surprises. What I don't like is that many devices that use the dock connector also use the USB pins and lock out the iPod navigation so I am forced to use the receiving devices control system.
My Ipod used to be hooked up from the headphone jack to the auxiliary input on my deck's brain..
Once I got a deck that had the dock connector my life became soo much easier and I may have talked myself into it.. But I believe I noticed an improvement in sound quality.
My Ipod used to be hooked up from the headphone jack to the auxiliary input on my deck's brain..
Once I got a deck that had the dock connector my life became soo much easier and I may have talked myself into it.. But I believe I noticed an improvement in sound quality.
I honestly thing the change in sound quality is really minute, but it's there. I use a cheap male to male 3.5mm headphone jack for my iPhone to my head unit, and I can't tell a difference between that and my USB thumb drive.
I used to be able to tell a difference when I was using my old third generation iPod. But that's because the output voltage was really low and I didn't set my SLI accordingly out of laziness and apathy.
Listen to an ipod or even a burned mp3 on a really good system and if you cannot tell the difference something is wrong.
Even in my car while driving listening to a burned mp3 vs the original cd i can promise i will be able to differentiate the two every time as long as i know the music.