haven't tried the C4, but the C3 is very affordable with better SQ than sansa and ipod. But i've seen many preferring the DX100 than the AK120 though, but i won't comment on them since i haven't tried the DX100.
The AK100 output impedance is around 22? Not suited for most IEMs as they are around 16, but then again numbers doesn't mean anything
FiiO X3 is almost comparable to AK100 and less than 3x the price which is really reasonable, but build quality and aesthetics doesn't come close to the AK100. So tempted on the AK100 just on the basis of looks lol 

22 Ohms Output Impedance

What is this?:

Almost just almost this player came in nearly flawless but it has a problem in the amp section that is perhaps unforgivable. The output impedance of the amplifier stage is 22 ohms and this is the cause of some very serious problems. Due to the effects of damping it is a rule of thumb that your earphone should have an impedance of roughly 8x the output impedance of the player, meaning ideally this should not be used with anything with impedance lower than 176 ohms. An effect of this is an obvious drop off of bass, reducing some headphones to something that is completely bass-less.

You also have the effects on frequency response, because a lot of headphones do not have flat impedance plots, especially multi armature IEMs with crossovers that can be quite all over the place, the high output impedance coming from the AK100 means less voltage enters the earphones and this makes the different frequencies get a significant amount of difference in volume resulting in a obvious colouration and screwed up frequency response. It is noticeably different and you will be able to tell what the measurements confirm.

thanks for all reply appreciate it

how about sansa Fuze or ipod touch?  colorfly C3 looks tempting too bad it doesnt support recording function
i researched lowyat about what the review of them
but never get the answer, cause some said its better while some said that better

p/s: sansa Fuze SQ doesnt same with sansa clip+?

while i heard that sansa SQ is just so so if without rockbox or lod, is that true?

I'm sorry but I have to disagree by your statement that the numbers do not mean anything as mismatching impedance has something to do with "damping" as it can affect sound reproduction in the FR chart or else why would Vinnie at Red Wine Audio started offering the service of modding to RWAK100 to correct its issues.
Source

Tyll on High Output Impedances

Hello people
I would like to buy a mp3 player with decent sound quality and big memory capacity
do not need any apps,games or internet function with it
Is iPod classic a good choice?
Budget under 1k
Thanks

Hello people
I would like to buy a mp3 player with decent sound quality and big memory capacity
do not need any apps,games or internet function with it
Is iPod classic a good choice?
Budget under 1k
Thanks

Try looking into the Fiio X3, very good sound quality with expandable storage through MicroSd. The UI might be a little clunky but it will get better with every update.

iPod classic would be a decent choice if you want big capacity for that price.

speaking of audio quality
is there an obvious gap between fiio x3 and ipod classic? 

feeling interested about this mp3 
do u know anything about x5?

Sorry I don't have the classic, only the nano
But pretty sure there is a difference, but how big the gap is subjective depending on the person.

The X5 isn't out yet, but it will be out before the end of the year. Not much is know except what's shown in the 1st posts here:

http://www.head-fi.org/t/661411/fiio-x5-th...uture-successor

I'm also looking forward to it, which is why I'm holding back on the X3

the x5 attracts me but it seems to have a pricetag of over rm 1k 

That's the point. It's around $400, which is pretty pricey for us. I'm considering as I won't need to look for another DAP for a long time and can focus on music instead. lol
But for the price, the X3 is a no-brainer.

i love the "wheel" design of ipod classic,iu and of course the large memory capacity but it lacks the audio performance of x3
feels contradicted 

Hello people
I would like to buy a mp3 player with decent sound quality and big memory capacity
do not need any apps,games or internet function with it
Is iPod classic a good choice?
Budget under 1k
Thanks

guys which of the sansa sounds the best?

those with rockbox capable