Lectrosonics R172 User Manual

INSTRUCTION MANUAL

R172 DUAL-RECEIVER

LECTROSONICS, INC.
581 Laser Road
Rio Rancho, NM 87124 USA
Tel [phone] or [phone]
fax [phone]
e-mail: [e-mail]
web: www.lectrosonics.com

INTRODUCTION

The R172 receiver is a fixed frequency design two channel wireless microphone receiver. Designed to offer two
simultaneous channels of wireless microphones, the R172 will can operate both channels from one antenna or two
for passive diversity operation. The dual antenna configuration reduces the probability of dropouts resulting from
multipath interference. Additionally, the audio output from this receiver can be either split into discrete channels or
mixed internally for maximum flexibility in any audio installation.

The RF signal first passes through RF filter coils coupled with ultra-low noise J-FETs. The J-FETs are used to
provide enough gain to compensate for inherent losses in the filter stages. Crystal controlled oscillators are used to
minimize drift and are stable over a wide range of temperatures. The output of the front end is then fed to a double
balanced diode mixer which generates an interference free IF signal. The mixer is followed by an LC filter stage and
the signal is amplified.

TABLE OF CONTENTS

Receiver Front Panel ............................................................................2

Receiver Rear Panel .............................................................................3

Operating Instructions: .........................................................................4

Set up sequence

Antenna Use and Placement.................................................................6

Multi-channel Audio Mixing ...................................................................7

Troubleshooting Guide..........................................................................8

Specifications .......................................................................................9

Factory Repair Service .........................................................................10

Front panel controls on the R172 are identical for each channel and operate independently from each other.

-- Indicates the modulation (audio level) of the incoming signal. The green LED indicates an

MODULATION

adequate modulation level. The red LED indicates maximum or "peak" modulation.

OUTPUT LEVEL

output levels of the XLR jacks in the rear by rotating the knob counter-clockwise.

LED -- Light when the transmitters are turned on. If the carrier signal is too weak to produce a quality signal,

RF

the lamp will go out. Each channel has it's own independent RF LED.

POWER

OFF ON SWITCH -

-- An output attenuator is used to reduce the audio output level of the receiver. Reduces the audio

NOTE: This control does not affect the
it also does not affect the output level of the "

LED -- Lights when the receiver is turned on.

This switch activates the receiver when set to the "ON" position.

RECEIVER FRONT PANEL

MODULATION

LINE LEVEL

display, the RF LED or the

" RCA jack.

LED --

POWER

Figure 1 R172 Front Panel

control.

SNGL.

will mix the signals

MIXED

ANTENNA

shipped with a telescoping whip antenna and a coaxial antenna. Rack mounted units are shipped with two coaxial
antennas.

ANTENNA MODE -

antennas are used set the switch to

12 VDC DC POWER

powering the unit from a 110 V AC outlet -- the receiver may also be powered from 12 volt DC sources using the
correct plug (Switchcraft S-760 power plug); the center pin is positive (+).

MIC LEVEL

inputs

LINE LEVEL

level of this RCA jack is not affected by the front panel

SEPARATE MIXED SWITCH ­SEPARATE

internally, allowing both channels to be output through either output jack.

AUX INPUTS

output. Also allows "stacking" multiple receivers.

terminals -- Standard BNC 50 ohm connectors for connecting the antennas. The R172 is normally

The unit may be operated as either a single antenna or a dual antenna system. If two

-- Connect the power supply here -- the CH-12 AC adapter is supplied with the receiver for

-- 3 pin XLR at microphone level (80mV max.); 200 ohm impedance for either balanced or unbalanced

-- RCA phono jack at "line" level (1 volt max); 1K ohm impedance for unbalanced inputs. The output

will keep the signals from the two channels discrete. Setting the switch to

-- RCA phono jack inputs accept external tape deck or other audio source; mixes audio with receiver

RECEIVER REAR PANEL

. If operating with only one antenna, set the switch to

DUAL

AUDIO OUTPUTS

OUTPUT LEVEL

Allows the "A" and "B" audio signals to be mixed, if desired. Setting the switch to

AUDIO INPUT

(mixing bus)