Universal Audio 1181 User manual

CX ENCODER/DECODER MODEL
1181
The UREI Model 1181 CX Encoder/Decoder offers the
mastering, production or mixdown facility the ability to
precisely record and playback according to the CBS
Technology CX disc noise reduction standard.
The CX noise reduction system is designed for phonograph
and video disc recording and reproduction. In the encoding
process which is done during disc mastering, all signals below
apreset threshold level are not compressed —in the CX
20 position, the threshold is -40 dB ref. 0VU*, and in the
CX 15 position, the threshold is -30 dB. Above this threshold,
all program is compressed with 2:1 ratio, using asignal-
dependent variable time constant. In decoding, complementary
expansion takes place, using the same signal-dependent
variable time constant.
The 1181 includes encoders for Preview and Program channels
and adecoder which may be switched to audition preview,
program or any “line level” external source. The encoders
are highly accurate 2:1 compressors switchable for CX 15 or
CX 20 conformance. High technology gain control blocks,
audio operational amplifiers and precision control circuits
assure excellent performance and long term stability. The
decoder or expander section is amirror of the encoder, using
the identical gain control circuitry to assure accurate play-
back tracking. Operating modes can also be remotely controlled
through arear panel connector so that the 1181 may be
installed wherever convenient.
*For phonograph records, 0VU corresponds to 3.54 cm/sec
groove modulation at 1kHz.
FEATURES:
•Preview, Program and Audition in two rack spaces
(3V2").
•Tamper resistant, screwdriver adjust setup controls
behind security cover.
•Fully automatic operation after initial setup. No special
techniques need be learned by the mastering engineer.
•Relay bypass with power off.
•LEDs allow setup with 0.1 dB resolution.
•Extremely low noise and distortion.
•Remote mode selection.
•Full metering matrix.
•Built and backed by UREI.
UNITED RECORDING ELECTRONICS INDUSTRIES
8460 SAN FERNANDO RD., SUN VALLEY, CALIFORNIA 91352
TELEX 65-1389 UREI SNVY [phone] MODEL
1181

TECHNICAL SPECIFICATIONS
ELECTRICAL; (Each Channel)
Inputs
Input Impedance
Input Level
Outputs
Output Load
Power Output
Frequency Response
Distortion
Control Law
Noise (Encoder)
(Decoder)
CONTROLS:
Front Panel
Metering
LEDs
External Connections
Power Requirements
Environment
PHYSICAL:
Dimensions
Finish
Weight
Shipping Weight
Accessories
Balanced bridging differential amplifiers, six each,
:10 kohms, used as balanced input.
5kohms, used as unbalanced (single ended) input.
:+20 dB maximum (Ref. 0.775 Vrms).
:Floating, transformer isolated, six each.
:600 ohms or greater.
:+24 dBm into 600 ohm load (12.28 V).
:+0, -0.5 dB, 20 Hz -20 kHz.
:Less than 0.1% THD, 50 Hz —15 kHz, at worst case gain.
:According to CBS Technology CX Standard, CX 15 or CX 20.
:Program -95 dB.
Preview -85 dB.
.(Referred to Input; Ref. 0.775 Vrms).
:Output -83 dB (15.7 kHz BW),
-95 dB (A-weighted).
Input Gain, Output Attenuator Trims, Meter Switches, Mode Switches,
Power Switch.
Two Meters, switch selectable to read any Input or Output.
“0” Reference +4 dB (Ref. 0.775 V).
Six LEDs to precisely indicate 1kHz, 3.54 cm/sec “0” point during setup.
Power LED.
Rear chassis barrier strips for inputs and outputs, plus barrier strip for remote
control of operating mode. Power through 3-wire lEC style connector.
110-120 VAC, or 220-240 VAC, 50/60 Hz, switch selectable, 25 watts.
Special option: 1181-100 Vfor 100 Voperation.
Operating 0°C to +50°C. Storage -20°C to +60°C.
483x89mm rack panel, depth behind panel 305mm (19 in x3)^ in x12 in).
Panel is 3.18mm (Vb in.) brushed clear anodized aluminum.
Chassis is cadmium plated steel.
7.5 kg (16.5 pounds).
9.3 kg (20.5 pounds).
Security Cover, SC 1181, included.
100 Vpower option available on request (1181-100 V).
6/82 1.5MF printed in U.S.A.

BEFORE PROCEEDING WITH COMPLETE UNPACKING AND SETUP,
CONSULT UNPACKING AND INSPECTION INSTRUCTIONS ON PAGE 2
model 1181
CX ENCODER/DECObER
United Hecording Electronics Industries
B46D BAN FERNANDO ROAD, SUN VALLEY, CALIFORNIA 91352
[phone]
Printed in U.S.A.
©Copyright 1981, UREI

UREI -1181 CX ENCODER/ uECODER
Preliminary Operating Instructions
SECTION I
Genera
1
Des cription :
The Model 1181 is designed to facilitate the cutting of master discs
to the C.B.S. standard for the CX process. Basically the process consists
of soft but precise compression during the mastering process and playback
through precise expansion to recreate the original dynamics with a15 to
20 dB reduction in perceived surface noise.
Jopolp^x
The 1181 consists of two stereo encoding (compression) sections designed
nominally to be used in the preview and program feed to the mastering
lathe, and astereo decoder (expander) to audition playback or feedback
from the lathe. Inputs are balanced differential amplifiers (5532 op amps)
and outputs are transistor boosted 5532 amps followed by very high quality
isolation transformers. Voltage controlled gain is facilitated with Allison
Research EGC 101 's.

SECTION II
INSPECTION AND INSTALLATION
Unpa cking and Inspec tion
Your Model 1181 was carefully packed at the factory, and the container
was designed to protect the unit from rough handling. Nevertheless, we
recommend careful examination of the shipping carton and its contents for
any sign of physical damage which could have occured in transit.
If damage is evident, do not destroy any of the packing material or the
carton, and immediately notify the carrier of apossible claim for damage.
Shipping claims must be made by the consignee.
The shipment should include:
Model 1181 CX Encoder/Decoder
UREI Preliminary Instructions
Two-Part Warranty Card bearing the
same serial number as the Model 1181
Rack mounting hardware
Env ironmen ta1Cons iderations
The system will operate satisfactorily over arange of ambient temperatures
from 0°C to +50° (+32°F to 122°F), and up to 80% noncondensing relative
humidity.
If the system is installed in an equipment rack with high heat producing
equipment (such as power amplifiers), adequate ventilation should be provided
in order to assure longest component life. Also, while circuitry susceptible
to hum pick-up is sufficiently shielded from moderate electromagnetic fields,
installation should be planned to avoid mounting the system immediately
adjacent to large power transformers, motors, etc.
Powering
The 1181 may be operated from either 115 -125 VAC or 220 -240 VAC mains
(50 Hz or 60 Hz, single phase). The nominal line voltage may be selected
with arear panel switch. BE SURE TO VERIFY BOTH THE ACTUAL LINE VOLTAGE,
AND THE SETTING OF THE VOLTAGE SELECTOR SWITCH BEFORE CONNECTING THE 1181
TO THE MAINS. (For operation in Japan (lOOV mains) aspecial power supply
transformer is required.)