ART Pro Audio USBDualTubePre - Two Channel USB Tube Preamp - Manual (Page 6)

Front Panel
LEFT GAIN and RIGHT GAIN knobs
These knobs adjust the input preamp gain for their respective channels. Use these controls to match the input signal to the levels re-
quired by the A/D and the outputs.
Increasing the LEFT or RIGHT GAIN will do a number of things. First, it will drive the tube more and create more tube warmth.
Second, it will optimize the discrete front end of the mic preamp for best noise performance. Finally, it will drive the OPTO COMP
harder when this function is used.
GAIN switch
Depressing the GAIN switch adds 20dB to the tube gain. This is useful when you need more gain than the input GAIN control can
provide. It also allows for more compression range of the Opto Compressor when required.
LOW CUT switch
The LOW CUT switch rolls off the response to signals lower than 70Hz. This helps to cut out low frequency rumble, wind noise, and
all types of very low frequency energy before it is amplified. When recording, this allows you to get more gain before clipping the
preamp, recorder, or computer and in a live situation you get more gain before clipping your amp.
PHASE switch
Use the PHASE switch to select the correct phase of the input signal to compensate for mic orientation and wiring. In the normal posi-
tion, output signals are in phase with the input signal on all jacks.
This function comes in handy to prevent a hollow sound, due to phase cancellations, when using multiple microphones. In a live
situation you may be able to get more gain before feedback by reversing the phase of a vocal microphone.
OPTO COMP switch
This switch activates the Optical Compressor. The switch cap is lit Green when active and turns Red when gain reduction is taking
place. Use the OPTO COMP switch to compress the dynamic range of the input signal and prevent clipping of the A/D without
sounding obtrusive.
Note: The compressor threshold is affected by the LEFT or RIGHT GAIN controls and GAIN switches, but not the LEFT or RIGHT
LEVEL controls.
LEFT LEVEL and RIGHT LEVEL knobs
These controls provide a means of adjusting the output level of the preamps. These knobs are affected by the STEREO/DUAL
switch and can act as either independent controls or MASTER LEVEL and BALANCE controls.
3