ART Pro Audio Auto-Tune Pre - Manual (Page 5)

The ¼-inch MAIN OUTPUT jack is unbalanced with an output impedance of 300
Ohms. The maximum output level is +18dBu.
The XLR MAIN OUTPUT jack is balanced with an output impedance of 600 Ohms.
The maximum output level is +24dBu. It can provide clean balanced signals for long
cable runs.
The 9 Volts AC power connector on the rear should only be connected to the power
supply that comes with the unit (9 Volts AC @ 1000 mA). 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.
REAR PANEL SWITCHES
The POWER 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. Remember to turn the Auto-Tune Pre on before turning on any
monitoring or power amplifiers.
The OUTPUT LEVEL switch adjusts the main output levels at both output jacks to
accommodate either high level (+4dBm) or low-level (-10 dBv) type of systems. If you
want to plug directly into an instrument amplifier or microphone level input then set the
switch to –10dBv. If you want a “hot” signal to drive down a long cable to a line level
input then set the switch to +4dBm. By doing this, you maximize the signal to noise
performance of your system.
The LOW CUT FILTER switch, when engaged, reduces very low frequency bass
response of the microphone preamp. This helps to minimize low frequency rumble and
wind and microphone handling noise when using microphones in live settings.
The PHANTOM POWER switch applies +48 Volt phantom power to the XLR input jack
for microphone powering, if needed. It turns on and off slowly and is current limited to
protect sensitive microphones and reduce audible pops. Ideally, when connecting a
microphone that requires phantom power, you should first turn down gain, then con-
nect 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
microphone.
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