DI INPUT: The DI input selects between Instrument (with
10 M input impedance at the front 1/4" jack, or 1M at the
rear jack) and Line (100K input impedance, with a -20dB pad at
both inputs). The 1/4" front and rear panel jacks are wired
so that the rear jack is disabled when the front jack is used.
MIC/DI: Selects between the MIC input (via the XLR
input connectors on the rear panel) or DI input signals (via
the front or rear 1/4" input jacks).
+48V: Supplies 48 volts to the XLR inputs for condenser
microphones requiring phantom power. Do not use with dynamic,
ribbon or tube mics.
0/-20: The -20 position inserts a 20 dB pad in front
of the mic input transformer.
+/-: Mic phase reverse switch, where '+' is normal
phase (input pin 2 hot), and '-' is inverted phase (input pin
MIC LO CUT: An 11 position rotary switch that provides
a gentle (6dB/octave) low frequency rolloff with 10 user-selectable
turnover frequencies (20 to 180Hz). The low cut filter does not
affect the DI input signal.
GAIN: An 11 position rotary switch that controls the gain
of the tube stage in 3dB steps. The range is: +33 to +63dB for
the mic input, +20dB to + 50dB for the DI instrument input, and
0 to + 30dB for the DI line input.
OUTPUT: A passive attenuator that controls the output
level to the XLR and 1/4" (parallel) output connectors.
By increasing the Gain (driving the tubes harder) and lowering
the Output level, subtle variations in the character of sound
are possible. For the 'cleanest' sound, set the OUTPUT control
to 10, and adjust the GAIN setting for the proper signal level.
OUTPUT: In the Output position, the VU meter indicates
the signal level at the XLR and 1/4" output connectors (post-Output
control). The meter is electronically isolated from the signal
path, and is calibrated to 0VU = +4dBu (1.23Vrms).
GAIN: In the Gain position, the VU meter indicates
the signal level of the tube gain stage (pre-Output control).
The meter is electronically isolated from the signal path, and
is calibrated to 0VU = +20dBu (7.75 Vrms).