Audioengine D3 Premium USB 24-bit DAC. The Audioengine D3 Premium 24-bit DAC (digital-to-analog converter) allows you to bypass your computer's headphone output and send music directly through a USB port for noticeably improved fidelity and a higher output. The D3 is a powerful yet portable converter with performance and features usually found in more expensive DACs and is the perfect interface between your computer and headphones or any music system. So buy this Audioengine D3 Premium USB 24-bit DAC Now £115.00.