[rockhoppernc]

Hi I am looking for a kick ass mac audio enhancement program.
is there such a thing and a downloadable amp-dac?

 

[albertnam]

If you're listening to high quality files through high-end equipment, programs such as Amarra may help to boost sound quality just a bit more. 
 
Otherwise, headphone amplifiers operate in the physical realm. It wouldn't matter anyways, because the audio will still be routed through your mac's internal DAC and amp. Also, a DAC is a digital-analog convertor. Your computer has no way of achieving this though software alone.
 
If you wanted to simulate the coloration of certain amp models, then I suppose some DSP could do the trick, but is not what you seem to be looking for. 

 

[third_eye]

I've had good results with Pure Music.