Rocktron Utopia G100 - Manual (Page 22)

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The HUSH ® function is accessible in all presets - regardless of the configuration currently
recalled.
HUSH is a patented single-ended noise reduction system. The HUSH system contained in
the UTOPIA G100, though modeled after the latest analog HUSH design, is a fully digital imple-
mentation achieved through Digital Signal Processing (DSP).
The low level expander of the HUSH system operates like an electronic volume control. The
analog version of the HUSH utilizes a voltage-controlled amplifier (VCA) circuit which can control
the gain between the input and the output from unity to 30, 40 or even 50(dB) of gain reduction.
When the input signal is above the user preset threshold point, the VCA circuit remains at unity
gain. (This means that the amplitude of the output signal will be equal to that of the input signal.)
As the input signal level drops below the user preset threshold point, downward expansion
begins. At this point the expander acts like an electronic volume control and gradually begins to
decrease the output signal level relative to the input signal level. As the input signal drops further
below the threshold point, downward expansion increases. A drop in the input level by 20(dB)
would cause the output level to drop approximately 40(dB) (i.e., 20(dB) of gain reduction). In
the absence of any input signal, the expander will reduce the gain so that the noise floor be-
comes inaudible.
HUSH ® Function
The HUSH I/O parameter simply determines whether the HUSH® circuit
is active for the current preset.
The HUSH THRESHOLD parameter determines the level at which
downward expansion begins. For example, if the HUSH THRESHOLD
was set at -20(dB) and the input signal dropped below -20(dB),
downward expansion would begin.
HUSH I/O
HUSH THRESH
The HUSH circuit is located after the A/D converter in the signal chain to reduce any noise
generated from the guitar and the A/D converter. This ensures a quiet input signal to the preamp
section. Because the preamp section of the UTOPIA G100 is digital, it is virtually noise-free (even
for the high-gain channels). Therefore, a quiet input signal to the preamp will result in a quiet output
signal.
The PARAMETER SELECT knob will allow you to access these Hush parameters: