Lectrosonics R170 User Manual

R170

RECEIVER

OPERATING INSTRUCTIONS

and trouble-shooting guide

LECTROSONICS, INC.

Rio Rancho, NM

INTRODUCTION

Thank you for selecting the Lectrosonics R170 receiver. This system provides reliable performance
and flexibility for a wide range of uses. The high selectivity provides protection from interference while
the high sensitivity increases the operating range and resistance to dropouts. A unique automatic
squelching system eliminates excess noise output from the receiver when the transmitter is turned off.

The R170 receiver was packaged for use with sound reinforcement and recording systems utilizing
balanced audio lines. Outputs for high or low impedance, balanced or un-balanced audio signals via
1/4", XLR and RCA jacks are provided. The versatile audio output section makes the R170 ideal for
applications where multiple audio feeds are required, such as providing PA system feed, "overflow
room" feed and tape recording signals simultaneously. This can be accomplished directly from the rear
panel connectors without external equipment.

In addition to the output jacks, a unique audio input on the rear panel allows "stacking" the receivers
together (up to three channels) in multi-channel applications without having to use a separate audio
mixer. This audio input jack also permits connection of a tape player to the receiver to mix tape
playback with the receiver output.

Matching FREEDOMIKE transmitters are available in several configurations for a wide variety of
applications in pro sound, pro video, theater/stage, and audio visual applications.

TABLE OF CONTENTS

INTRODUCTION .......................................... 1

GENERAL DESCRIPTION ................................... 2

RECEIVER FRONT PANEL ................................... 3

RECEIVER REAR PANEL .................................... 4

USE AND PLACEMENT ..................................... 5

OPERATING INSTRUCTIONS ................................. 6

INDICATOR QUICK REFERENCE .............................. 6

MULTI-CHANNEL AUDIO MIXING .............................. 7

MIXING AN EXTERNAL TAPE DECK WITH RECEIVER OUTPUT ...... 7

TROUBLESHOOTING ....................................... 8

REPLACEMENT PARTS and ACCESSORIES ..................... 9

SERVICE AND REPAIR ..................................... 10

RETURNING UNITS FOR REPAIR ............................. 10

SPECIFICATIONS AND FEATURES ............................ 11

LIMITED ONE YEAR WARRANTY .............................. 12

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GENERAL DESCRIPTION

The R170 receiver utilizes a two stage quartz crystal oscillator to assure that the frequency will not drift.
Custom made high Q toroidal filters in the RF and IF stages reject interfering adjacent signals and
provide over 100 dB of image rejection. Dual gate MOS FET semi-conductors in the RF amplifier and
mixer provide excellent sensitivity and resistance to RF overload. A two stage, crystal controlled
oscillator is individually trimmed to the exact operating frequency when each receiver is manufactured
to insure that the frequency will not drift.

The audio section contains a noise reduction "compandor" to suppress audible noise without impairing
the natural dynamics of the audio signal. A 6-pole active filter in the audio path eliminates all
supersonic and subsonic noise in order to increase the compandor tracking accuracy in weak signal
conditions. A time delayed, correlation squelch system is employed in the R170. This circuit is highly
stable and never needs adjustment by the user.

A standard XLR jack provides a balanced 200 Ohm output, variable from -20dBm to -70dBm
(microphone level). A 1/4" phone jack provides a balanced 600 Ohm output, variable from 0dBm to

-50dBm (line level). An RCA phono jack provides a 1K Ohm output at 1 Volt maximum (line level) for
tape recorders or other PA systems. The output level control is a balanced "H" pad attenuator network
using precision resistors. It reduces the output of the XLR and 1/4" jacks, but does not affect the
output of the RCA jack. Noise and distortion are very low and not affected by the setting of the output
level control.

The CH-12 remote DC power supply isolates the R170 receiver audio circuitry from AC ground, which
eliminates ground loops. This also allows the R170 to be powered from external 12 Volt power sources
other than the CH-12 AC adapter.

The R170 receiver is compatible with all Lectrosonics 170 and 185 series transmitters.

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RECEIVER FRONT PANEL

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

indicates an adequate modulation level. The red LED indicates maximum or "peak" modulation.
OUTPUT - VOLUME ATTENUATOR - An output attenuator is used to adjust the output level of the two

balanced outputs (XLR and 1/4") on the rear panel of the receiver. When the knob is in a fully clock­wise position, the output at the jack will be 100mV when the signal is at full modulation. The attenuator
knob works like a regular volume control. As you turn the knob counter clockwise the audio output of
the receiver will be lowered.

NOTE: This control does not affect the MOD LEVEL display, the RF LED or the
POWER LED -- it also does not affect the output level of the "LINE OUT" RCA jack.

OFF - AUDIO MUTE - ON -- This slide switch turns the power off and on and provides a "mute"
function in the center position. This switch should be in the AUDIO MUTE position when the transmitter
MIC LEVEL or GAIN adjustment is being made. This muting function also prevents turn-on and turn-off
transients ("thumps" or "pops" in the sound system) that can occur when switching the receiver on and
off.

RF lamp -- Lights when the transmitter is turned on. If the carrier signal is too weak to produce a
quality signal, the lamp will go out.

POWER lamp -- Lights when the receiver is turned on.

Figure 1 - R170 Front Panel

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