[HeadLover]

I know that for speakers we use Pre-Amp
So
Can the same thing be used for headphones? and will it improve sound quality?
And if it can't, why not ?

 

[Navyblue]

A pre amp is only used when your amp doesn't have a volume knob (i.e. a power amp). So far all non portable headphone amp comes with volume knob and there is no reason to pass your audio signal through an additional component in the sound quality perspective. Every single component in the audio chain degrades sound quality, the better ones just do it less.

 

[JohanK]

A headphone amp basically is a preamp that can drive low impedance loads (that is headphones) too. Hence most of the higher end headphone amps also offer outputs to a power amp to enable it to function as both a headphone amp and a preamp in the same system.

if you want an example of this, notice that for example the GS1/GSX are marketed as preamps too:

http://www.headamp.com/home_amps/index.htm

Also notice that the higher end offerings from Ray Samuels are in fact labelled as preamps in the product overview and not headphone amps:

http://raysamuelsaudio.com