1200/2200 Sound Level Meter Operator’s Manual15
Technical Information
CAUTION: When installing or removing the microphone, do not unscrew
the protective grid. Do not touch the metal foil microphone diaphragm
under this grid as permanent damage may result.
Figure 6. Typical microphone response Type 1
Figure 7. Typical microphone response Type 2
1200/2200 Sound Level Meter Operator’s Manual 16
Technical Information
5.3 Microphone Preamplifier Extension Cables
On 1200R (Remote) units the preamplifier is removable by unscrewing the
black plastic collar below the preamplifier housing. The 1200 will drive
up to a 10 foot cable with minimal loss. Quest offers the following lengths
of remote cable for use with the 1200:
#59-899 ICM-2 Microphone Cable (2 foot length)
#59-733 ICM-10 Microphone Cable (10 foot length)
#59-734 ICM-50 Microphone Cable (50 foot lenght)
The calibration level at 1 kHz is affected by less than 0.1 dB with the
insertion of either of these cables. Therefore, there is no need to
recalibrate when the cable is attached.
5.4 Input Buffer Circuitry
The high impedance input circuitry of the 1200 will accept up to a 2.0 volt
RMS signal. With the microphone and preamp removed, other transducer
devices may be connected to give a dB readout on the meter. To remove
the preamplifier unscrew the black plastic collar below the preamp
housing. Only use pins 1 and 3 for the AC signal input. NEVER connect
to pins 2 and 4. To input an electrical signal requires a special connector,
Quest part number 14-739. Figure 9 shows the function of each of the
pins within the meter input connector.
Figure 9. Meter Input Connector
Figure 8. Frequency/Amplitude Limitations with Extension Cables
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