Product Manual

Figure 3-4 Limitter and Filter-Thru Switches
Filter-Thru Switch (Amplifier Right Side)
Figure 3-4 shows a side view of the amplifier with the Filter-Thru switch in the
OFF position. When the Filter-Thru switch is turned ON, the filter switches on
the face of the amplifier are completely by-passed, and there is no filtering of
sounds at all. The user hears all sounds from 50 Hz to 15,000 Hz (or to the extent
of his or her hearing).
The amplifier’s filters are most useful during “ground miking”, when extraneous
noises from wind, traffic, equipment, etc. interfere the most with the user’s abil-
ity to distinguish the leak sounds. Often these extraneous noises are not troubling
interferences during leak surveys at hydrants, meters, and valves. At these loca-
tions, the leak sounds are easily heard, and often the user will wish to do leak
surveys with the Filter-Thru switch turned ON (to hear the clearest, un-filtered
sounds).
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