9762A
– Preamplifier
Owner’s Manual
Page 7
RTZ Professional Audio
The SP (signal present) and OL (overload) LED’s provide input stage
signal monitoring. In normal use the OL should not light to prevent signal
distortion. The signal quality degrades rather quickly once the OL
threshold is reached. The SP and OL LED’s monitor channel activity and
clipping for the signal source currently selected by the DI switch.
The eight LED VU meter monitors the master output level from the line
amplifier stage. The first LED lights at around
–20 dB with subsequent
steps at
–10 dB, –6 dB, –3 dB, 0 dB, +3 dB, +10 dB and +18 dB. The
master LEVEL control is used to trim the output level using the VU meter
as a level reference.
4.4
Line Amplifier Stage
The line amplifier stage input level is controlled by the master LEVEL
control. The LEVEL control acts as a channel fader to trim the line
amplifier output as needed. In general, the LEVEL control should be set
to the maximum position (fully CW) and the input GAIN control is then
adjusted to obtain the desired output signal level. If the output signal is
slightly “hot”, use the LEVEL control to trim the output level back to
obtain the desired output signal level.
In situations where distortion or warmth is desired, the input GAIN setting
may be set “hot” and the output LEVEL control is used to trim the output
back to a suitable level. Use care with this technique to avoid overdriving
the input stage excessively as the signal becomes very ugly sounding at
extremes. Also, keep in mind the line amplifier stage is capable of
delivering very large output level swings (around 40V peak-to-peak!);
excessive signal levels could
damage the input stages of gear being
driven by the 9762.