Orban 275A User manual

Operating Manual
Automatic
Stereo Synthesizer
Model 275A

IMPORTANT NOTE: Refer to the unit’s rear panel for your Model Number.
Model Number: Description:
275A/U Stereo Synthesizer, 115V
275A/E Stereo Synthesizer, 230V
OPTIONS:
Model Number: Description:
275ARC Remote Control
275ASPK Spare Parts Kit
SCI Clear Security Cover
MANUAL:
Part Number: Description
95053-000-02 275A Manual
CAUTION: TO REDUCE the risk of electrical shock, do NOT REMOVE COVER (OR BACK).
NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRICAL SHOCK, DO NOT EXPOSE THIS
APPLIANCE TO RAIN OR MOISTURE.
This symbol, wherever it appears,
alerts you to the presence of uninsulated
dangerous voltage inside the enclosure —voltage
that may be sufficient to constitute arisk of shock.
This symbol, wherever it appears,
alerts you to important operating and
maintenance instructions in the accompanying
literature. Read the manual.

IMPORTANT SAFETY INSTRUCTIONS
All the safety and operating instructions should be read before the appliance is operated.
Retain Instructions: The safety and operation instructions should be retained for future reference.
Heed Warnings: All warnings on the appliance and in the operating instructions should be adhered to.
Follow Instructions: All operation and user instructions should be followed.
Water and Moisture: The appliance should not be used near water (e.g., near abathtub, washbowl, kitchen sink, laundry tub, in awet
basement, or near aswimming pool, etc.).
Ventilation: The appliance should be situated so that its location or position does not interfere with its proper ventilation. For example, the
appliance should not be situated on abed, sofa, rug, or similar surface that may block the ventilation openings; or, placed in abuilt-in
installation, such as abookcase or cabinet that may impede the flow of air through the ventilation openings.
Heat: The appliance should be situated away from heat sources such as radiators, heat registers, stoves, or other appliances (including
amplifiers) that produce heat.
Power Sources: The appliance should be connected to apower supply only of the type described in the operating instructions or as
marked on the appliance.
Grounding or Polarization: Precautions should be taken so that the grounding or polarization means of an appliance is not defeated.
Power-Cord Protection: Power-supply cords should be routed so that they are not likely to be walked on or pinched by items placed
upon or against them, paying particular attention to cords at plugs, convenience receptacles, and the point where they exit from the appliance.
Cleaning: The appliance should be cleaned only as recommended by the manufacturer.
Non-USe Periods: The power cord of the appliance should be unplugged from the outlet when left unused for along period of time.
Object and Liquid Entry: Care should be taken so that objects do not fall and liquids are not spilled into the enclosure through
openings.
Damage Requiring Service: The appliance should be serviced by qualified service personnel when:
The power supply cord or the plug has been damaged; or
Objects have fallen, or liquid has been spilled into the appliance; or
The appliance has been exposed to rain; or
The appliance does not appear to operate normally or exhibits amarked change in performance; or
The appliance has been dropped, or the enclosure damaged.
Servicing: The user should not attempt to service the appliance beyond that described in the operating instructions. All other servicing
should be referred to qualified service personnel.
The Appliance should be used only with acart or stand that is recommended by the manufacturer.
Safety Instructions (European)
Notice For U.K. Customers If Your Unit Is Equipped With APower Cord.
WARNING: THIS APPLIANCE MUST BE EARTHED.
The cores in the mains lead are coloured in accordance with the following code:
GREEN and YELLOW -Earth BLUE -Neutral BROWN -Live
As colours of the cores in the mains lead of this appliance may not correspond with the coloured markings identifying the terminals in your
plug, proceed as follows:
The core which is coloured green and yellow must be connected to the terminal in the plug marked with the letter E, or with the earth symbol,
(4-), or coloured green, or green and yellow.
The core which is coloured blue must be connected to the terminal marked Nor coloured black.
The core which is coloured brown must be connected to the terminal marked Lor coloured red.
The power cord is terminated in aCEE7/7 plug (Continental Europe). The green/yellow wire is connected directly to the unit's chassis. If
you need to change the plug and if you are qualified to do so, refer to the table below.
WARNING: If the ground is defeated, certain fault conditions in the unit or in the system to which it is connected can result in full line
voltage between chassis and earth ground. Severe injury or death can then result if the chassis and earth ground are touched simultaneously.
CONDUCTOR WIRE COLOR
Normal Alt
LLIVE BROWN BLACK
NNEUTRAL BLUE WHITE
EEARTH GND GREEN-YELLOW GREEN
AC Power Cord Color Coding

Safety Instructions (German)
Gerat nur an der am Leistungsschild vermerkten Spannung und Stromart betreiben.
Sicherungen nur durch solche, gleicher Stromstarke und gleichen Abschaltverhaltens ersetzen. Sicherungen nie uberbrucken.
Jedwede Beschadiguna des Netzkabels vermeiden. Netzkabel nicht knicken Oder quetschen. Beim Abziehen des Netzkabels den
Stacker und nicht das Kabel enfassen. Beschadigte Netzkabel sofort auswechseln.
Gerat und Netzkabel keinen ubertriebenen mechanischen Beaspruchungen aussetzen.
Um Beruhrung gefahrlicher elektrischer Spannungen zu vermeiden, dart das Gerat nicht geoffnet warden. Im Fall von Betriebsstorun-
gen dart das Gerat nur Von befugten Servicestellen instandgesetzt warden. Im Gerat befinden sich keine, durch den Benutzer
reparierbare Teile.
Zur Vermeidung von elektrischen Schiagen und Feuer ist das Gerat vor Nasse zu schiitzen. Eindringen von Feuchtigkeit und
Fliissigkeiten in das Gerat vermeiden.
Bei Betriebsstorungen bzw. nach Eindringen von Fliissigkeiten Oder anderen Gegenstanden, das Gerat sofort vom Netz trennen und
eine qualifizierte Servicestelle kontaktieren.
Safety Instructions (French)
On s'assurera toujours que la tension et la nature du courant utilise correspondent bien aceux indiques sur la plaque de I'appareil.
N'utiliser que des fusibles de meme intensity et du meme principe de mise hors circuit que les fusibles d’origine. Ne jamais shunter les
fusibles.
Eviter tout ce qui risque d’endommager le cable seceur. On ne devra ni le plier, ni I’aplatir. Lorsqu'on debranche Iappareil, tirer la fiche
et non le cable. Si un cable est endommage, le remplacer immediatement.
Ne jamais exposer I'appareil ou le cable aune contrainte mecanique excessive.
Pour eviter tout contact averc une tension electrique dangereuse, on noouvrira jamais I'appareil. En cas de dysfonctionnement,
I’appareil ne peut etre repare que dans un atelier autorise. Aucun element de cet appareil ne peut etre repare par Iutilisateur.
Pour eviter les risques de decharge electrique et d'incendie, proteger I'appareil de I'humidite. Eviter toute penetration d'humidite ou fr
liquide dans I'appareil.
En cas de dysfonctionnement ou si un liquide ou tout autre objet apenetre dans I'appareil couper aussitot I’appareil de son alimentation
et s'adresser aun point de service apresvente autorise.
Safety Instructions (Spanish)
Hacer funcionar el aparato solo con la tension yclase de corriente sehaladas en la placa indicadora de caracteristicas.
Reemplazar los fusibles solo por otros de la misma intensidad de corriente ysistema de desconexion. No poner nunca los fusibles en
puente.
Proteger el cable de alimentacion contra toda clase de danos. No doblar oapretar el cable. Al desenchufar, asir el enchufe yno el
cable. Sustituir inmediatamente cables danados.
No sometar el aparato yel cable de alimentacion aesfuerzo mecanico excesivo.
Para evitar el contacto con tensiones electricas peligrosas, el aparato no debe abrirse. En caso de producirse fallos de funcionamiento,
debe ser reparado solo por talleres de servicio autorizados. En el aparato no se encuentra ninguna pieza que pudiera ser reparada
por el usuario.
Para evitar descargas electricas eincendios, el aparato debe protegerse contra la humedad, impidiendo que penetren esta oliquidos
en el mismo.
En caso de producirse fallos de funcionamiento como consecuencia de la penetration de liquidos uotros objetos en el aparato, hay
que desconectarlo inmediatamente de la red yponerse en contacto con un taller de servicio autorizado.
Safety Instructions (Italian)
Far funzionare I'apparecchio solo con la tensione eil tipo di corrente indicati sulla targa riportante idati sulle prestazioni.
Sostituire idispositivi di protezione (valvole, fusibili ecc.) solo con dispositivi aventi lo stesso amperaggio elo stesso comportamento
di interruzione. Non cavallottare mai idispositivi di protezione.
Evitare qualsiasi danno al cavo di collegamento alia rete. Non piegare oschiacciare il cavo. Per staccare il cavo, tirare la presa emai
il cavo. Sostituire subito icavi danneggiati.
Non esporre I'apparecchio eil cavo ad esagerate sollecitazioni meccaniche.
Per evitare il contatto con le tensioni elettriche pericolose, I'apparecchio non deve venir aperto. In caso di anomalie di funzionamento
I’apparecchio deve venir riparato solo da centri di servizio autorizzati. Nell'apparecchio non si trovano parti che possano essere riparate
dalrutente.
Per evitare scosse elettriche oincendi, I'apparecchio va protetto dall’umidita. Evitare che umidita oliquidi entrino nell'apparecchio.
In caso di anomalie di funzionamento rispettivamente dopo la penetrazione di liquidi ooggetti nell'apparecchio, staccare immedi-
atamente I'apparecchio dalla rete econtattare un centra di servizio qualificato.

Operating Manual
Automatic
Stereo Synthesizer
Model 275A

This manual is part number 95053-000-02.
200 -FB -5/96
©Copyright 1996.
orbon
HAHarman International Company
1525 Alvarado Street, San Leandro, CA 94577 USA
Phone: [phone] •Fax: [phone] •E-mail: [email protected]

Table of Contents
SECTION 1: SYSTEM DESCRIPTION
AND APPLICATION
1-1 Performance Highlights
1-2 Fig. 1-1: Conceptual Block Diagram
1-3 Product Overview
SECTION 2: INSTALLATION
2-1 Overview of Installation Procedure
2-2 Fig. 2-1: Rear Panel
2-3 Remote Control Panel 273A/RC
2-3 Fig. 2-2: Chassis Configuration
for Remote Control
2-4 Power-up Jumpers
2-4 Fig. 2-3: Powerup Jumpers
2-5 AC Power
2-5 Fig. 2-4: AC Line Color Code
2-5 Mounting Rack Requirements
2-6 Audio Connections, Operating Level
2-7 Recognition Switch
2-7 Initial Program Tests
2-7 External Automation
2-8 Fig. 2-5: Control Interface Inputs
2-8 Fig. 2-6: Loopthrough Diagram
2-
9Registration Card
SECTION 3: OPERATING INSTRUCTIONS
Fig. 3-1: Front-panel Controls
3-
1Summary
3-2 General Operating Instructions
3-4 Further Discussion of Functions
SECTION 4: MAINTENANCE
4-1 Introduction
4-1 Preventive Maintenance
4-1 Corrective Maintenance
4-1 Service Access
4-2 Component Replacement
4-2 Replacement Parts
4-2 Replacement of PCB Components
4-4 Troubleshooting IC Opamps
4-4 Factory Service
4-
5Shipping Instructions
SECTION 5: ALIGNMENT AND
PERFORMANCE EVALUATION
5-
1General
5-1 Power Supply
5-1 Signal Processing Circuitry
5-2 Audio Path Alignment and Verification
5-4 Fig. 5-1: Noise Reduction Response
5-4 Fig. 5-2: Noise Reduction Response,
lOdB Below Expansion Threshold
5-4 Fig. 5-3: Frequency Response in
Synthesize Mode
5-4 Fig. 5-4: Synthesizer Response,
Narrow Mode
5-4 Fig. 5-5: Synthesizer Response,
Wide Mode
5-5 Control Circuit Bandpass Filter
Performance Verification
5-5 Fig. 5-6: Control Circuit
Bandpass Filter Response
5-5 Automatic Recognition Circuit Tests
5-6 275A/RC Interface Tests
5-7 User Control Interface Logic Tests

SECTION 6s CIRCUIT DESCRIPTION APPENDIX A: GUIDE FOR THE MASTER
CONTROL OPERATOR
6-1 Main Audio Path
6-1 Input Buffer
6-1 Crossfade Circuit APPENDIX Bs INTERNAL TRIMS
6-2 Noise Reduction Circuit
6-3 Fig. 6-1: IC12 Pinout, Diagram
6-3 Stereo Synthesizer APPENDIX C: INSTALLATION OF REMOTE
6-3 Auto Polarity Circuit CONTROL PANEL 275A/RC
6-4 L+R Peak Detector
6-4 L+R/L-R Comparator, Time Constant C-l Introduction
6-5 Mono/Stereo Recognition Circuit C-l Connector
6-5 Single Channel Recognition C-l Fig. C-l: Connector Wiring Diagram
6-6 Center Channel Recognition C-2 Cable
6-7 Control Logic C-2 Table C-l: Potentially Useful Cables
6-7 General C-2 Additional Remote Control Panels
6-7 Comb Bandwidth C-3 Temporary Removal of 275A/RC Panel
6-7 Noise Reduction OPERATE/DEFEAT
6-8 Auto Polarity ON/OFF
6-8 Basic Mode Switching, General APPENDIX D: CONSTRUCTING APHASE-
6-8 Input Decode and Latches DIFFERENCE NETWORK
6-9 Pulse/Continuous Logic
6-9 User Interface Status Sensor D-l Theory
6-10 Crossfade Ramp Generator D-2 Fig. D-l: Phase Differences
6-10 Latch and Left/Right Decode Logic D-2 Fig. D-2: Mono Sum Errors
6-11 Active Status Lamps D-2 Implementation
6-11 Automation Lockout Circuit D-3 Application and Operation
6-11 Remote Control D-4 Fig. D-3: Network Schematic
6-12 Power Supply
6-12 LED Brightness
APPENDIX E: PARTS LIST
APPENDIX F: SPECIFICATIONS
APPENDIX G: SCHEMATICS AND PARTS
LOCATOR DRAWINGS

Front Panel
Hear Panel
ORBAN MODEL 275A AUTOMATIC STEREO SYNTHESIZER

SECTION 1:
System Description And Application
1.PERFORMANCE —Stereo inputs and outputs
HIGHLIGHTS Designed to be placed permanently in series with the program line.
—Fully compatible with mono receivers
They reproduce the synthesizer's original mono input.
—Audio-controlled switching between true and synthesized stereo
Synthesizer is activated when audio is absent on one channel and, optionally,
when both channels are nearly equal. In addition, local and remote manual
override control is available.
—Smooth "cross-fade" switching between modes
Program-adaptive crossfade rate avoids clicks and pops.
—Automatically detects and corrects polarity-reversals
Automatically corrects "out-of-phase" stereo inputs.
—Phase-shift-derived comb filter stereo synthesis
Orban's patented phase-shift-derived comb filter stereo synthesis technique. Two
remote-selectable stereo synthesis modes allow matching the spatial perspective
to the program material. "Narrow" mode centers dialogue. "Wide" is more
dramatic on music and effects.
—Single-ended dynamic noise reduction
Acombination of program-controlled lowpass filtering and downward expansion
is available for noise reduction on synthesized material. lOdB reduction of hiss
and hum is typically achieved.
—Optically-isolated automation control of all functions
—Optional 19" rack-mount Remote Control Panel
Duplicates main unit control panel.
—Fully-balanced, transformerless inputs and outputs
+26dBm clipping level permits use with +4 or +8dBm lines.
—Space-saving chassis
Mounts in 13/4" of rack space.
1-1