Front Panel
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3
NOTE: The left side of the 6176 front panel contains all preamp controls, while the right side
contains all limiter / compressor controls. All controls (except the Level, Attack, Release, Input, and
Output knobs) are stepped, allowing settings to be easily reproduced.
(1) Gain -
Adjusts the gain of the input stage in 5 dB increments. Turning the Gain switch clockwise
raises the gain. Because this also has the effect of reducing negative feedback (
see page 25
),
the Gain switch alters the amount of the input tube’s harmonic distortion, a major contribution to the
“warm” sound characteristic of tube equipment. The higher the Gain setting, the more coloration the
6176 will impart to the incoming signal.
(2) Input Select -
Determines which of the following three inputs is active: Mic, Line, or Hi-Z. The
Mic and Hi-Z inputs each provide two different impedance settings.
Mic -
Selects the signal arriving at the rear panel balanced XLR Preamp MIC INPUT
connection. (
see #7 on page 9
) The impedance for the Mic input can be set to 500 ohms
or 2.0K ohms. Switching between these two positions while listening to a connected
microphone may reveal a different tonal quality and/or gain difference. Typically, a
microphone preamplifier should have input impedance roughly equal to about 10 times the
microphone output impedance. For example, if your microphone has an output impedance of
approximately 200 ohms, the switch should be set to the 2.0K position. However, making
music is not necessarily about adhering to technical specifications, so feel free to
experiment with the settings to attain the desired sound: you will not harm your microphone
or the 6176.
Line -
Selects the signal arriving at the rear panel balanced XLR Preamp LINE INPUT
connection. (
see #6 on page 9
) This connection has an input impedance of approximately
13K ohms
and is intended to accommodate mixers, DAWs, tape machines, other mic
preamps, signal processors, or any device with a line level output, such as keyboards, sound
modules and drum machines. Using this input, the 6176 can act as a “tone box” for line-
level signals, offering a variety of sonic colors based on front panel control settings.
