A DAC, or digital to analogue converter, is the device that translates digitally stored information from a laptop, iPod or other such device into the analogue sound that we can hear.

Is USB DAC necessary?

If the USB DAC includes a headphone amplifier with a decent power output, then yes, it will help drive your headphones properly to get the most out of them. But it's the amplifier that's the important part in your situation. ... Yes, using the DAC in your receiver will give you great audio from your CD transport.

Is a DAC really necessary?

A DAC takes digital audio information and converts it to an analog signal. That signal then travels to an amplifier, and then to your speakers or headphones where you hear it. A DAC is an essential component of any PC's audio system.