ART Pro Audio USBDualTubePre - Two Channel USB Tube Preamp - Manual (Page 9)

S/PDIF Output
The S/PDIF connector allows the USB Dual Tube Pre to connect to a wide range of consumer and professional equipment. This out-
put is .5V p-p (when connected) and has a 75 Ohm impedance. The S/PDIF output is controlled by the Rear SAMPLE RATE switch
and is independent of the USB sample rate. This output transmits a channel status identifying the correct sample rate and that copy-
right protection is turned off. Equipment driven by this output should be set to "slave" to this signal for correct timing syncronization.
The front panel SIGNAL/CLIP LEDs is calibrated to provide an accurate means of adjusting the preamp output levels for the best
A/D performance.
USB jack
The USB connection allows your USB Dual Tube Pre to send and receive audio from your computer. There is a separate A/D for the
USB interface that operates at a sample rate that is controlled by your computer. This interface is fully compliant with the USB 2.0
specification and is backward compatible with the USB 1.0 spec.
9 Volts AC POWER jack
The power connector on the rear should only be connected to the power supply that comes with the unit. 9 to 10 Volts AC @ 1000 mA
is required typically. Make sure that you specify AC and not DC if you have to replace this supply. Internal circuitry converts this
power to the higher voltages needed for the tube and phantom power sections.
POWER switch
This switch allows you to power off the unit when it is not in use. Please allow the tube and internal circuitry to warm up
for one to two minutes before use if the unit has been powered off
.
S/PDIF SAMPLE RATE switch
This switch sets the sample rate for the A/D converter connected to the S/PDIF jack ONLY. When in the "out" positions the sample
rate is 44.1KHz. When depressed (lit), it sets the rate to 48KHz.
PHANTOM POWER switch
The PHANTOM POWER switch applies +48 Volt phantom power to the XLR input jacks for powering your microphones, if
needed. It is slow at turning on and off and is current limited to protect sensitive microphones and reduce pops. Ideally, when connect-
ing a microphone that requires phantom power, you should first turn down the gain, then connect the microphone, then switch on the
phantom power, and finally bring the gain back up to the desired level. This minimizes pops in your system and stress on the micro-
phone.
6