Rf bypassing, Line level signals, Wiring hookups for different sources – Lectrosonics UM700 User Manual
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UM700
RF BYPASSING
2 WIRE MIC
3 WIRE MIC
Some mics require RF protection to keep the radio signal
from affecting the capsule, even though the transmitter
input circuitry is already RF bypassed (see schematic
diagram).
If the mic is wired as directed, and you are having
difficulty with squealing, high noise, or poor frequency
response; RF is likely to be the cause.
The best RF protection is accomplished by installing RF
bypass capacitors at the mic capsule. If this is not
possible, or if you are still having problems, capacitors
can be installed on the mic wires inside the TA5F connector housing.
Install the capacitors as follows: Use 330 pF capacitors. Capacitors are available from Lectrosonics. Please specify
the part number for the desired lead style.
Leaded capacitors: P/N 15117
Leadless capacitors: P/N SCC330P
The Lectrosonics M150-700 lavalier mic is bypassed correctly for use with the UM700 and is the recommended
microphone for the 700 Series wireless system.
LINE LEVEL SIGNALS
The normal hookup for line level signals is: Signal Hot to pin 5, Signal Gnd to pin 1, pin 4 jumped to pin 1, and pin
3 jumped to pin 1. This gives a 40dB attenuator that allows signal levels much higher than 3V to be applied without
limiting.
If more headroom is needed, insert a 100k resistor in series with pin 5. Put this resistor inside the TA5F connector to
minimize noise pickup.
If lower than normal line levels (less than 1V) are expected, use this hookup: Signal Hot to pin 5, Signal Gnd to pin
1, and pin 4 jumpered to pin 1. This provides a 20dB attenuator allowing signals as high as 3V to be applied without
limiting.
WIRING HOOKUPS FOR DIFFERENT SOURCES
CAPSULE
CAPSULE
SHIELD
AUDIO
SHIELD
AUDIO
BIAS
TA5F
CONNECTOR
TA5F
CONNECTOR
Preferred locations for bypass capacitors
Alternate locations for bypass capacitors
SHIELD
AUDIO
BIAS
3 WIRE ELECTRET MIC
POSITIVE BIAS
PIN
1
2
3
1
2
3
4
5
SHIELD
AUDIO
2 WIRE ELECTRET MIC
NEGATIVE BIAS
4
TA5F
5
PLUG
SHIELD
AUDIO
2 WIRE ELECTRET MIC
POSITIVE BIAS
SLEEVE
1
PIN
SHIELD
2
AUDIO
3
TIP
4
1
2
3
4
5
LINE LEVEL
TA5F
RCA or 1/4 " PLUG
5
PLUG
PIN
1
2
3
4
1
2
3
4
5
TA5F
5
PLUG
PIN
1
2
3
4
1
2
3
4
5
TA5F
5
PLUG
(See notes on ‘LINE LEVEL SIGNALS” above.)
3
1
2
PIN
PIN
PIN
1
SHIELD
Dynamic LO Z mic or electret with
manufacturers power supply.
1
1
2
2
2
3
3
3
1
2
3
4
5
4
4
1
2
3
4
5
DYNAMIC
TA5F
TA5F
MIC LEVEL
5
5
PLUG
PLUG
SHIELD
BIAS
AUDIO
3 WIRE ELECTRET MIC
NEGATIVE BIAS
SHIELD
TIP
PIN
5
4
3
2
1
SLEEVE
Mini Plug
DATA
1
2
3
4
5
TA5F
PLUG
Encryption Cable
LECTROSONICS, INC.
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