Body ground, Line level signals, Wiring hookups for different sources – Lectrosonics UM250c User Manual
Page 11
UHF Belt-Pack Transmitter
The best RF protection is accomplished by installing RF
2 WIRE MIC
3 WIRE MIC
bypass capacitors at the mic capsule. If this is not pos
sible, or if you are still having problems, capacitors can be
installed on the mic wires inside the TA5F connector hous
ing.
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
All Lectrosonics lavalier mics are already bypassed and do not need any additional capacitors installed for proper
operation.
BODY GROUND
Caution
When wiring the connector, do not use the connector body for any electrical connections. A common mistake is to use the connector body
as an audio ground. The connector body is already used as an RF ground on VHF models and no other use is permitted.
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
distortion.
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
distortion.
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
PIN
1
2
3
4
5
PIN
SHIELD
SHIELD
AUDIO
2 WIRE ELECTRET MIC
NEGATIVE BIAS
1
1
2
2
3 WIRE ELECTRET MIC
3
3
1
2
3
4
5
POSITIVE BIAS
4
4
TA5F
TA5F
5
5
PLUG
PLUG
AUDIO
BIAS
SLEEVE
PIN
PIN
SHIELD
SHIELD
1
1
2
2
AUDIO
AUDIO
2 WIRE ELECTRET MIC
TIP
3
3
POSITIVE BIAS
4
1
2
3
4
5
LINE LEVEL
1
2
3
4
5
4
TA5F
TA5F
RCA or 1/4 " PLUG
5
PLUG
5
PLUG
3
1
2
PIN
PIN
PIN
Dynamic LO Z mic or electret with
manufacturers power supply.
SHIELD
1
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
Rio Rancho, NM – USA
11