The Radial USB-Pro is a high-resolution stereo digital audio converter (DAC) and direct box that is designed to connect to any computer system to seamlessly transfer digital audio to analog. A stereo pair of balanced XLR audio outputs with adjustable level control then feeds the signal to a microphone preamplifier, PA system, mixing console or even a powered speaker! Made for plug and play simplicity, the USB-Pro will automatically be listed as an available sound card in the audio settings in all popular operating systems including Windows XP, Windows 7/8, and Mac OSX. Connection to a computer is accomplished through a standard USB type-B port. Digital-to-analog conversion can be monitored on headphones through the 3.5mm analog output to check signal quality and level before connecting to a sound system. A mono-sum switch may be engaged to check for phasing or for connection to a mono system. Should hum or buzz caused by ground loops be encountered, two recessed side-access switches allow the user to insert isolation transformers into the signal path. To further reduce susceptibility to noise, this is augmented with a ground lift switch that lifts pin-1 on both XLR jacks. As with all Radial products, the USB-Pro is designed to handle the rigors of professional touring. Our unique book-end design creates protective zones around the switches, connectors and controls to keep them out of harm's way. Inside, our time-tested I-beam construction assures the sensitive internal PC board will not torque, which could cause premature part failure. Finally, a full bottom no-slip pad provides mechanical isolation and electrical insulation to ensure quiet operation. FeaturesHigh performance 24bit digital audio converterReady to use without the need of a driver3.5mm analog headphone output to check signalBalanced Lo-Z outputs with switchable isolation