Shure FP33 - Manual (Page 5)

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the VU meter, refer to the Internal Modifiable Func-
tions section.
11. Input Gain Control: Adjusts the gain level of each in-
put channel. Rotating the knob counterclockwise re-
duces the gain and raises the input clipping point. Use
a low control setting to handle “hotter” input signals
without distortion. With the FP33 input circuit, micro-
phones with a “hot” output may be used without an in-
line pad (attenuator). For best performance, adjust
each Input Gain control so the associated Input Level
LED illuminates red only on the loudest signal peaks.
12. Input Low-Cut Filter Switch: Provides low-frequen-
cy roll-off to reduce wind noise and rumble. When us-
ing the filter, the frequency response is down 6 dB at
150 Hz. The roll-off slope is 6 dB per octave.
13. Master Gain—Right Channel Output: The outer
ring controls the Right channel output gain. The dual-
clutched control lets the Right and Left outputs be ad-
justed individually. Set it to “0 dB” for unity gain.
14. Master Gain—Left Channel Output: The inner knob
controls the Left channel output gain. The dual-
clutched control lets the Right and Left outputs be ad-
justed individually. Set it to “0 dB” for unity gain.
Note: The 1 kHz tone oscillator level is set by the
Master Level controls. To calibrate other devices,
adjust the Master Level controls for a 0 VU re-
sponse.
15. Output Peak Limiter Switch: Activates two fast-act-
ing, peak-responding limiters, one for each output
channel. Limiters help prevent overload distortion
from unexpected loud input signals. The limiter activa-
tion is indicated by the Output Peak/Limiter LEDs,
which illuminate green.
The limiters may be changed to: operate indepen-
dently; be linked as a stereo pair; activate at thresh-
olds from 0 dBm to +15 dBm; and have release time
constants of 0.1 second or 1 second. See the Internal
DIP Switches and Limiter Threshold Adjustment for
instructions.
16. Left/Right Channel Output Level Meters: 0 VU is
preset at a +4 dBm output level. This may be recali-
brated for each meter by an internal trim potentiometer.
See the VU Meter Adjustment paragraph for instruc-
tions.
Note: Mechanical meters are used because LCD me-
ters do not operate properly in cold weather; fluores-
cent meters drain batteries too quickly; and LED me-
ters are difficult to see in sunlight.
17. Monitor Input Switch: In the center position, this
switch sends the post-master audio to the headphone
output. In the left (locking ) or right (momentary) posi-
tion, it sends the audio signal from the Monitor In jack
to the headphone output.
18. Headphone Gain Control (Inner Knob): Adjusts the
headphone volume level.
WARNING: The headphone circuit is capable of
producing high volume levels that can damage the
user’s hearing. Make sure the headphone volume
setting is low (fully CCW) before putting on the
headphones.
19. Headphone Monitor Mode Switch (Outer Ring):
The user can monitor the FP33 output as: Stereo; Right
channel only; Mono (Left + Right); or Left channel only.
Note: This switch also affects the Monitor In signal.
When using a stereo MS microphone, such as the
Shure VP88, the user may wish to pass the mic signal
through the FP33 as separate Mid and Side signals,
yet hear decoded stereo in the headphones. Using the
Headphone MS Matrix, the user can monitor the FP33
output as: Discrete (Mid and Side); Side only, Stereo
(decoded MS), or Mono (Mid only). Refer to the Inter-
nal DIP Switch table for instructions on activating the
Headphone MS Matrix.