The Nuforce uDAC-2 is a portable high-performance USB DAC meaning Digital Analog Converter as well as a headphone amp all together in a tiny package. When I say portable I mean it's tiny enough to be portable but you cannot use it with your iPod on the go because the uDAC-2 does require USB power and does not have any batteries making it the best friend your laptop can have and saving you some desk space. Why do you need one of these you ask? Check out the full review after the break where I'll go over similar questions.
How small exactly is the uDAC-2? Most of you may have one of these iPhone 4's around right? The uDAC-2 is pretty tiny compared to an iPhone 4 as you can see above. Then again, it isn't a real portable amp for headphones and earphones because it still requires a USB power source like your laptop. Nuforce makes more expensive amps and DACs that are made primarily for home use with much more flexibility like their Icon-2 which has inputs for gaming consoles.
The only inputs the uDAC-2 has is a USB input for power and of course it's also used to transfer the digital audio from your computer. The big plus of using the uDAC-2 is having the pleasure of avoiding your presumably crappy built-in headphone jack and sound card. Your laptop's sound card may not be such a good performer and that is one of the biggest reasons why you should use the uDAC-2. The quality of sound coming from the uDAC-2 will be much cleaner and clearer than your headphone jack. Most laptops today still have bad sound cards inside of them but if you're using a Mac then you're already in a better position.
I did not notice a night and day transformation in the sound quality when comparing the uDAC-2 to my built-in sound card inside my MacBook Pro. I did however manage to hear the difference in sound quality and found that the uDAC-2 improved the sound quality and removed the hissing I had while using the built-in headphone port.
There is a volume knob at the front of the device and a white LED power indicator as well as the headphone/earphone output. On the back of the uDAC-2 are left and right audio RCA outputs and a S/PDIF Coaxial output. This brings me to a second reason why you would need to use the uDAC-2. You will be able to connect your home stereo speakers and desktop speakers that require such connection with your computer while amping the sound at the same time. To correctly setup the uDAC-2 or any other amp for that matter, you will need to set your computers or other audio source's volume all the way to the maximum and only use the volume knob on the uDAC-2 to control the volume. This is just the right way to use amps and it will give you the best sound quality as well.
If you experience hissing sounds using your built-in headphone port then the uDAC-2 will eliminate that instead of you having to replace your sound card or even purchasing an external sound card. I should note that if you already have a really good sound card, you will not notice any difference in sound quality using the uDAC-2.
The uDAC-2 comes in three color finishes and is built very well and uses aluminum construction. Overall I think the uDAC-2 performs very well and offers a few methods of connecting your computer with external speakers and headphones. Price $129.