[fmlfml]

Does DAP = DAC?? 
Is there got any build-in amp?
If I interested in AK100, do I need an amp to boost it up?

 

[megaMANX6]

DAP - Digital Audio Player Play your music files, Have Amp as it have its own volume control
DAC - Digital to Analog Converter Just convert the flac, mp3 etc to soundwave which we human can hear No amp unless stated

 

[AnakChan]

Does DAP = DAC?? 
Is there got any build-in amp?
If I interested in AK100, do I need an amp to boost it up?

What are you using for headphones with the AK100?

 

[fmlfml]

Quote:

What are you using for headphones with the AK100?

I'm using ES5/ED8

 

[AnakChan]

Quote:

I'm using ES5/ED8

 
Dunno about ES5. But Ed8 (presumably you mean Ultrasone Edition 8's), then they're low impedance. Then IMHO yes having an external amp is nicer. If it's a high impedance headphone of (if we go by the 8x guideline, then it's 22x8 =) 176 ohm and above, you shouldn't need an external amp.
 
This is one of the reasons why RWA did the RWAK100 mod, so that it's low impedance to high impedance friendly - i.e. you can use the RWAK100 without an external amp.