Headphone jack vs. Line Out in a Personal Media Player

I know this might be a silly question but I need to ask it. I just purchased a Cowon Q5 Personal Media Player that I will be using mostly in the car. I bought it for FLAC support and the fact I can upgrade the factory 40 GB hard drive to a 120 GB hard drive. Since it too has a USB and runs Windows CE 5 I can hook up an external drive loaded with FLACs. Great for them long trips!

I’ll be hooking it up via aux to a Panasonic deck. L & R RCA’s at the deck end, 3.5 mm headphone jack on the players end for headphones. The Line Out uses a IO Port located at the bottom of the unit with supplied cord that includes componant, composite, coaxial optical & L & R RCA’s. Everythings already in place due to me using a Rockboxed iRiver ihp-120 for the last few years that I unfortenetly need to retire. The car is a 97 Buick LeSabre with a JL Audio stereo. (sub, amps, componants).

I know I want to use the Line out but my question is: What exactly are the differences between the two? I did a quick google and with other units (ipods) headphone jack is amplified, the line out isn’t. I’m going to assume this is the same with the Cowon Q5. I need to get the best sound possible out of this player. Apparently this is one of the better sounding players out there but I don’t think its going to beat the iRiver. Will the best sound be achieved by using the line out and not headphone jack? Is it a big no-no to use the headphone jack when not using headphones?

Here’s a link to the player with the specs. Website though doesn’t allow a direct link so a little bit of navigation is needed. At the top of the site, click on pmp and then on the right Cowon Q5W. Theres a bunch of pretty pictures, scroll down an inch and you will see specs tab.

Any advice & knowledge is much appreciated!

http://www.cowonglobal.com/

Audio quality wise, there really should be almost no difference. But the line-out is set at a fixed voltage (volume level) whereas the headphone output is controlled by your volume knob. I guess the line-out should be a bit cleaner, there would be less opportunity to clip the output, depending how good the amp design is in the player.

But ofcourse try both, but realize that the headphone output will probably have the potential to make a higher signal, which you can interpret as being louder through the speakers, but louder will not mean a cleaner signal.

ok thanks!