Cowon J3 : is an amp needed ?

For the first part, an amp will improve the sound quality, how much though depends on what kind of amp you get and the quality of that amp.

For the second question, yea there are better players; the t51/sflo2 and Hickman players are going to sound better, although if you heavily use the equalizer the other players don't have ones of the same quality.

What is the difference between an umamped J3 and using an amp like ALOs Rx or pico slim. Is it really that much of a difference?

 

Anyone answer this?

Well this will depend on the genres of music you listen to and the type of headphones you use. 

 

For starters, you are amping a headphone out so the only benefit you will get is more power and the added signature that the amp will give. 

 

What headphones are you going to be amping? 

Almost everything sounds better with an amp and the P51 is a stellar choice. Keep in mind that when everyone says "it depends" they arn't saying "don't buy the T51 or the P51", or anything for that matter, they are just saying that the best choice is your choice. If you have the means, then buy something that's well received by the community (the P51 for example) it will blow you away(go head-fi). But don't let your voyage end there, trade your amp for equal-value amps in the FT forum, you woun't loose money and you will develop a prefrence. I'd say buy the amp first, Iphones don't sound egregious, and FIND OUT IF THERE ARE MEETS IN YOUR AREA, you will be able to try stuff you havn't bought, which is a dream. 

 

So, don't get thwarted by the "it depends on your prefrence" kind of people, they arn't trying to talk you out of that P51, just jump in there and hit that "buy now" button, we all did it and now it's your turn. I shy away from recommending a DAP because you already have one, even though it's made by apple, and those Denon headphones will come to life if you give them the power. Goodluck!

^ If you can't make it to meets, try buying from somewhere that has a 30-day money back deal.

^ I second and third that