Studer 928 Service Manual

Studer 928

Mixing Console

1.General

List of all Plug-In Modules

Layout and Designations, Specifications Block Diagram

2.Operation

3.Jumper Settings Alignment

4. Plug-In Units of the Input Section (1.928…)

Inputs, Groups,

AUX Master Units

Talkback/Monitoring

5. Plug-In Units of the Meter Panel

Signaling

Metering

Generator

6. EU Standard PCBs

7.Connectors

8.Wiring Lists

9. Wiring Diagrams

Bus Boards

10.19” Rack-Mount Power Supply

Operating and Service Instructions

Prepared and edited by	Copyright by Studer Professional Audio GmbH
Studer Professional Audio GmbH	Printed in Switzerland
Technical Documentation	Order no. 10.27.4251 (Ed.0702)
Althardstrasse 30
CH-8105 Regensdorf - Switzerland	Subject to change

Studer is a registered trade mark of Studer Professional Audio GmbH, Regensdorf

SAFETY / SECURITE / SICHERHEIT

To reduce the risk of electric shock, do not remove covers (or back). No user-serviceable parts inside. Refer servicing to qualified service personnel.

Afin de prévenir un choc électrique, ne pas enlever les couvercles (où l’arrière) de l’appareil. Il ne se trouve à l’intérieur aucune pièce pouvant être réparée par l’usager.

Um die Gefahr eines elektrischen Schlages zu vermeiden, entfernen Sie keine Geräteabdeckungen (oder die Rückwand). Überlassen Sie Wartung und Reparatur qualifiziertem Fachpersonal.

This symbol is intended to alert the user to presence of uninsulated “ dangerous voltage” within the apparatus that may be of sufficient magnitude to constitute a risk of electric shock to a person.

Ce symbole indique à l'utilisateur qu'il existent à l'intérieur de l'appareil des “ tensions dangereuses” . Ces tensions élevées entrainent un risque de choc électrique en cas de contact.

Dieses Symbol deutet dem Anwender an, dass im Geräteinnern die Gefahr der Berührung von “ gefährlicher Spannung” besteht. Die Grösse der Spannung kann zu einem elektrischen Schlag führen.

This symbol is intended to alert the user to the presence of important instructions for operating and maintenance in the enclosed documentation.

Ce symbole indique à l’utilisateur que la documentation jointe contient d'importantes instructions concernant le fonctionnement et la maintenance.

Dieses Symbol deutet dem Anwender an, dass die beigelegte Dokumentation wichtige Hinweise für Betrieb und Wartung enthält.

CAUTION: Lithium battery. Danger of explosion by incorrect handling. Replace by battery of the same make and type only.

ATTENTION: Pile au lithium. Danger d'explosion en cas de manipulation incorrecte. Ne remplacer que par un modèle de même type.

ACHTUNG: Explosionsgefahr bei unsachgemässem Auswechseln der Lithiumbatterie. Nur durch den selben Typ ersetzen.

ADVARSEL: Lithiumbatterei. Eksplosinsfare. Udskinftning ma kun foretages af en sagkyndig of som beskrevet i servicemanualen (DK).

I

SAFETY / SECURITE / SICHERHEIT

FIRST AID

(in case of electric shock)

1.Separate the person as quickly as possible from the electric power source:

•by switching off the equipment

•or by unplugging or disconnecting the mains cable

•pushing the person away from the power source by using dry insulating material (such as wood or plastic).

•After having sustained an electric shock, always consult a doctor.

WARNING!

DO NOT TOUCH THE PERSON OR HIS CLOTHING BEFORE THE POWER IS TURNED OFF, OTHERWISE YOU STAND THE RISK OF SUSTAINING AN ELECTRIC SHOCK AS WELL!

2. If the person is unconscious:

•check the pulse,

•reanimate the person if respiration is poor,

•lay the body down, turn it to one side, call for a doctor immediately.

PREMIERS SECOURS

(en cas d'électrocution)

1.Si la personne est dans l'impossibilité de se libérer:

•Couper l'interrupteur principal

•Couper le courant

•Repousser la personne de l'appareil à l'aide d'un objet en matière non conductrice (matière plastique ou bois)

•Après une électrocution, toujours consulter un médecin.

ATTENTION!

NE JAMAIS TOUCHER UNE PERSONNE QUI EST SOUS TENSION, SOUS PEINE DE SUBIR EGALEMENT UNE ELECTROCUTION.

2.En cas de perte de connaissance de la personne électrocutée:

•Controller le pouls

•Si nécessaire, pratiquer la respiration artificielle

•Placer l'accidenté sur le flanc et consulter un médecin.

ERSTE HILFE

(bei Stromunfällen)

1.Bei einem Stromunfall die betroffene Person so rasch wie möglich vom Strom trennen:

•Ausschalten des Gerätes

•Ziehen oder Unterbrechen der Netzzuleitung

•Betroffene Person mit isoliertem Material (Holz, Kunststoff) von der Gefahrenquelle wegstossen

•Nach einem Stromunfall sollte immer ein Arzt aufgesucht werden.

ACHTUNG!

EINE UNTER SPANNUNG STEHENDE PERSON DARF NICHT BERÜHRT WERDEN. SIE KÖNNEN DABEI SELBST ELEKTRISIERT WERDEN!

2.Bei Bewusstlosigkeit des Verunfallten:

•Puls kontrollieren,

•bei ausgesetzter Atmung künstlich beatmen,

•Seitenlagerung des Verunfallten vornehmen und Arzt verständigen.

II

SICHERHEIT / SAFETY

Installation

Installation

Vor der Installation des Gerätes müssen die hier aufgeführten und auch die weiter in dieser Anleitung mit bezeichneten Hinweise gelesen und während der Installation und des Betriebes beachtet werden.

Untersuchen Sie das Gerät und sein Zubehör auf allfällige Transportschäden.

Ein Gerät, das mechanische Beschädigung aufweist oder in welches Flüssigkeit oder Gegenstände eingedrungen sind, darf nicht ans Netz angeschlossen oder muss sofort durch Ziehen des Netzsteckers vom Netz getrennt werden. Das Öffnen und Instandsetzen des Gerätes darf nur von Fachpersonal unter Einhaltung der geltenden Vorschriften durchgeführt werden.

Falls dem Gerät kein konfektioniertes Netzkabel beiliegt, muss dieses durch eine Fachperson unter Verwendung der mitgelieferten Kabel-Gerätedose IEC320/C13 oder IEC320/C19 und unter Berücksichtigung der einschlägigen, im geweiligen Lande geltenden Bestimmungen angefertigt werden; siehe unten.

Vor Anschluss des Netzkabels an die Netzsteckdose muss überprüft werden, ob die Stromversorgungsund Anschlusswerte des Gerätes (Netzspannung, Netzfrequenz) innerhalb der erlaubten Toleranzen liegen. Die im Gerät eingesetzten Sicherungen müssen den am Gerät angebrachten Angaben entsprechen.

Ein Gerät mit einem dreipoligen Gerätestecker (Gerät der Schutzklasse I) muss an eine dreipolige Netzsteckdose angeschlossen und somit das Gerätegehäuse mit dem Schutzleiter der Netzinstallation verbunden werden (Für Dänemark gelten Starkstrombestimmungen, Abschnitt 107).

Before you install the equipment, please read and adhere to the following recommendations and all sections of these instructions marked with .

Check the equipment for any transport damage.

A unit that is mechanically damaged or which has been penetrated by liquids or foreign objects must not be connected to the AC power outlet or must be immediately disconnected by unplugging the power cable. Repairs must only be performed by trained personnel in accordance with the applicable regulations.

Should the equipment be delivered without a matching mains cable, the latter has to be prepared by a trained person using the attached female plug (IEC320/C13 or IEC320/C19) with respect to the applicable regulations in your country - see diagram below.

Before connecting the equipment to the AC power outlet, check that the local line voltage matches the equipment rating (voltage, frequency) within the admissible tolerance. The equipment fuses must be rated in accordance with the specifications on the equipment.

Equipment supplied with a 3-pole appliance inlet (equipment conforming to protection class I) must be connected to a 3-pole AC power outlet so that the equipment cabinet is connected to the protective earth conductor of the AC supply (for Denmark the Heavy Current Regulations, Section 107, are applicable).

Female plug (IEC320), view from contact side:
L	live; brown	National American Standard:	Black
N	neutral; blue		White
PE	protective earth; green and yellow		green
Connecteur femelle (IEC320), vue de la face aux contacts:
L	phase; brun	Standard national américain:	Noir
N	neutre; bleu		Blanc
PE	terre protective; vert et jaune		Vert
Ansicht auf Steckkontakte der Kabel-Gerätesteckdose (IEC320):
L	Phase; braun	USA-Standard:	Schwarz
N	Nulleiter; blau		Weiss
PE	Schutzleiter; gelb/grün		grün

III

SICHERHEIT / SAFETY

Zugentlastung für den Netzanschluss

Zum Verankern von Steckverbindungen ohne mechanische Verriegelung (z.B. IEC-Kaltgerätedosen) empfehlen wir die folgende Anordnung:

Vorgehen: Der mitgelieferte Kabelhalter ist selbstklebend. Bitte beachten Sie bei der Montage die folgenden Regeln:

1.Der Untergrund muss sauber, trocken und frei von Fett, Öl und anderen Verunreinigungen sein. Temperaturbereich für optimale Verklebung: 20...40° C.

2.Entfernen Sie die Schutzfolie auf der Rückseite des Kabelhalters und bringen sie ihn mit kräftigem Druck an der gewünschten Stelle an. Lassen sie ihn unbelastet so lange wie möglich ruhen – die maximale Klebekraft ist erst nach rund 24 Stunden erreicht.

3.Die Stabilität des Kabelhalters wird erhöht, wenn Sie ihn zusätzlich verschrauben. Zu diesem Zweck liegen ihm eine selbstschneidende Schraube sowie eine M4-Schraube mit Mutter bei.

4.Legen Sie das Kabel gemäss Figur in den Halter ein und pressen Sie die Klemme kräftig auf, bis das Kabel fixiert ist.

Mains connector strain relief

For anchoring connectors without a mechanical lock (e.g. IEC mains connectors), we recommend the following arrangement:

Procedure: The cable clamp shipped with your unit is auto-adhesive. If mounting, please follow the rules below:

1.The surface to be adhered to must be clean, dry, and free from grease, oil or other contaminants. Best application temperature range is 20...40° C.

2.Remove the plastic protective backing from the rear side of the clamp and apply it firmly to the surface at the desired position. Allow as much time as possible for curing. The bond continues to develop for as long as 24 hours.

3.For improved stability, the clamp can be fixed with a screw. For this purpose, a self-tapping screw and an M4 bolt and nut are included.

4.Place the cable into the clamp as shown in the illustration above and firmly press down the internal top cover until the cable is fixed.

IV

UMGEBUNGSBEDINGUNGEN / AMBIENT CONDITIONS

Lufttemperatur und Feuchtigkeit

Allgemein

Die Betriebstauglichkeit des Gerätes oder Systems ist unter folgenden Umgebungsbedingungen gewährleistet:

EN 60721-3-3, Set IE32, Wert 3K3.

Diese Norm umfasst einen umfassenden Katalog von Parametern; die wichtigsten davon sind: Umgebungstemperatur +5...+40 °C; rel. Luftfeuchtigkeit 5...85% – d h. weder Kondensation noch Eisbildung; abs. Luftfeuchtigkeit 1...25 g/m³; Tem- peratur-Änderungsrate < 0,5 °C/min. In den folgenden Abschnitten wird darauf näher eingegangen.

Unter den genannten Bedingungen startet und arbeitet das Gerät oder System problemlos. Ausserhalb dieser Spezifikationen möglicherweise auftretende Probleme sind in den folgenden Abschnitten beschrieben.

Umgebungstemperatur

Geräte und Systeme von Studer sind allgemein für einen Umgebungstemperaturbereich (d h. Temperatur der eintretenden Kühlluft) von +5...+40 °C ausgelegt. Bei Installation in einem Schrank muss der vorgesehene Luftdurchsatz und dadurch die Konvektionskühlung gewährleistet sein. Folgende Tatsachen sind dabei zu berücksichtigen:

1.Die zulässige Umgebungstemperatur für den Betrieb der Halbleiter-Bauelemente beträgt 0 °C bis +70 °C (commercial temperature range for operation).

2.Der Luftdurchsatz der Anlage muss gewährleisten, dass die austretende Kühlluft ständig kühler ist als 70 °C.

3.Die mittlere Erwärmung der Kühlluft soll 20 K betragen, die maximale Erwärmung an den heissen Komponenten darf somit um weitere 10 K höher liegen.

4.Zum Abführen einer Verlustleistung von 1 kW bei dieser

zulässigen mittleren Erwärmung ist eine Luftmenge von 2,65 m³/min notwendig.

Beispiel: Für ein Rack mit einer Leistungsaufnahme P = 800 W ist eine Kühlluftmenge von 0,8 * 2,65 m³/min nötig, entsprechend 2,12 m³/min.

5. Soll die Kühlfunktion der Anlage (z.B. auch bei LüfterAusfall oder Bestrahlung durch Spotlampen) überwacht werden, so ist die Temperatur der Abluft unmittelbar oberhalb der Einschübe an mehreren Stellen im Rack zu messen; die Ansprechtemperatur der Sensoren soll 65 bis 70 °C betragen.

Reif und Tau

Das unversiegelte System (Steckerpartien, Halbleiteranschlüsse) verträgt zwar leichte Eisbildung (Reif). Mit blossem Auge sichtbare Betauung führt jedoch bereits zu Funktionsstörungen. In der Praxis kann mit einem zuverlässigen Betrieb der Geräte bereits im Temperaturbereich ab –15 °C gerechnet werden, wenn für die Inbetriebnahme des kalten Systems die folgende allgemeine Regel beachtet wird:

Wird die Luft im System abgekühlt, so steigt ihre relative Feuchtigkeit an. Erreicht diese 100%, kommt es zu Niederschlag, meist in der Grenzschicht zwischen der Luft und einer kühleren Oberfläche, und somit zur Bildung von Eis oder Tau an empfindlichen Systemstellen (Kontakte, IC-Anschlüsse etc.). Ein störungsfreier Betrieb mit interner Betauung, unabhängig von der Temperatur, ist nicht gewährleistet.

Air temperature and humidity

General

Normal operation of the unit or system is warranted under the following ambient conditions defined by:

EN 60721-3-3, set IE32, value 3K3.

This standard consists of an extensive catalogue of parameters, the most important of which are: ambient temperature +5...

+40° C, relative humidity 5...85% – i.e. no formation of condensation or ice; absolute humidity 1...25 g/m³; rate of temperature change < 0,5 °C/min. These parameters are dealt with in the following paragraphs.

Under these conditions the unit or system starts and works without any problem. Beyond these specifications, possible problems are described in the following sections.

Ambient temperature

Units and systems by Studer are generally designed for an ambient temperature range (i.e. temperature of the incoming air) of +5...+40 °C. When rack mounting the units, the intended air flow and herewith adequate cooling must be provided. The following facts must be considered:

1.The admissible ambient temperature range for operation of the semiconductor components is 0 °C to +70 °C (commercial temperature range for operation).

2.The air flow through the installation must provide that the outgoing air is always cooler than 70 °C.

3.Average heat increase of the cooling air shall be 20 K, allowing for an additional maximum 10 K increase at the hot components.

4.In order to dissipate 1 kW with this admissible average heat increase, an air flow of 2,65 m³/min is required.

Example: A rack dissipating P = 800 W requires an air flow of

0,8 * 2,65 m³/min which corresponds to 2,12 m³/min.

5. If the cooling function of the installation must be monitored (e.g. for fan failure or illumination with spot lamps), the outgoing air temperature must be measured directly above the modules at several places within the rack. The trigger temperature of the sensors should be 65 to 70 °C.

Frost and dew

The unsealed system parts (connector areas and semiconductor pins) allow for a minute formation of ice or frost. However, formation of dew visible with the naked eye will already lead to malfunctions. In practice, reliable operation can be expected in a temperature range above –15 °C, if the following general rule is considered for putting the cold system into operation:

If the air within the system is cooled down, the relative humidity rises. If it reaches 100%, condensation will arise, usually in the boundary layer between the air and a cooler surface, together with formation of ice or dew at sensitive areas of the system (contacts, IC pins, etc.). Once internal condensation occurs, troublefree operation cannot be guaranteed, independent of temperature.

V

UMGEBUNGSBEDINGUNGEN / AMBIENT CONDITIONS

Vor der Inbetriebnahme muss das System auf allfällige interne Betauung oder Eisbildung überprüft werden. Nur bei sehr leichter Eisbildung kann mit direkter Verdunstung (Sublimation) gerechnet werden; andernfalls muss das System im abgeschalteten Zustand gewärmt und getrocknet werden.

Das System ohne feststellbare interne Eisbildung oder Betauung soll möglichst homogen (und somit langsam) mit eigener Wärmeleistung aufgewärmt werden; die Lufttemperatur der Umgebung soll ständig etwas tiefer als diejenige der Systemabluft sein.

Ist es unumgänglich, das abgekühlte System sofort in warmer Umgebungsluft zu betreiben, so muss diese entfeuchtet sein. Die absolute Luftfeuchtigkeit muss dabei so tief sein, dass die relative Feuchtigkeit, bezogen auf die kälteste Oberfläche im System, immer unterhalb 100% bleibt.

Es ist dafür zu sorgen, dass beim Abschalten des Systems die eingeschlossene Luft möglichst trocken ist (d.h. vor dem Abschalten im Winter den Raum mit kalter, trockener Luft belüften und feuchte Gegenstände, z.B. Kleider, entfernen).

Die Zusammenhänge sind im folgenden Klimatogramm ersichtlich. Zum kontrollierten Verfahren gehören Thermometer und Hygrometer sowie ein Thermometer innerhalb des Systems. Beispiel 1: Ein Ü-Wagen mit einer Innentemperatur von 20 °C und 40% relativer Luftfeuchtigkeit wird am Abend abgeschaltet. Sinkt die Temperatur unter +5 °C, bildet sich Tau oder Eis. Beispiel 2: Ein Ü-Wagen wird morgens mit 20 °C warmer Luft von 40% relativer Luftfeuchtigkeit aufgewärmt. Auf Teilen, die kälter als +5 °C sind, bildet sich Tau oder Eis.

Before putting into operation, the system must be checked for internal formation of condensation or ice. Only with a minute formation of ice, direct evaporation (sublimation) may be expected; otherwise the system must be heated and dried while switched off.

A system without visible internal formation of ice or condensation should be heated up with its own heat dissipation, as homogeneously (and subsequently as slow) as possible; the ambient temperature should then always be lower than the outgoing air.

If it is absolutely necessary to operate the system immediately within warm ambient air, this air must be dehydrated. In such a case, the absolute humidity must be so low that the relative humidity, related to the coldest system surface, always remains below 100%.

Ensure that the enclosed air is as dry as possible when powering off (i.e. before switching off in winter, aerate the room with cold, dry air, and remove humid objects as clothes from the room).

These relationships are visible from the following climatogram. For a controlled procedure, thermometer and hygrometer as well as a thermometer within the system will be required.

Example 1: An OB-van having an internal temperature of 20 °C and rel. humidity of 40% is switched off in the evening. If temperature falls below +5 °C, dew or ice will be forming.

Example 2: An OB-van is heated up in the morning with air of 20 °C and a rel. humidity of 40%. On all parts being cooler than +5 °C, dew or ice will be forming.

VI

WARTUNG / MAINTENANCE

Wartung und Reparatur

Durch Entfernen von Gehäuseteilen, Abschirmungen etc. werden stromführende Teile freigelegt. Deshalb müssen u.a. die folgenden Grundsätze beachtet werden: Eingriffe in das Gerät dürfen nur von Fachpersonal unter Einhaltung der geltenden Vorschriften vorgenommen werden.

Vor Entfernen von Gehäuseteilen muss das Gerät ausgeschaltet und vom Netz getrennt werden.

Bei geöffnetem, vom Netz getrenntem Gerät dürfen Teile mit gefährlichen Ladungen (z. B. Kondensatoren, Bildröhren) erst nach kontrollierter Entladung, heiße Bauteile (Leistungshalbleiter, Kühlkörper etc.) erst nach deren Abkühlen berührt werden.

Bei Wartungsarbeiten am geöffneten, unter Netzspannung stehenden Gerät dürfen blanke Schaltungsteile und metallene Halbleitergehäuse weder direkt noch mit nichtisoliertem Werkzeug berührt werden.

Zusätzliche Gefahren bestehen bei unsachgemässer Handhabung besonderer Komponenten:

•Explosionsgefahr bei Lithiumzellen, Elektrolyt-Kon- densatoren und Leistungshalbleitern

•Implosionsgefahr bei evakuierten Anzeigeeinheiten

•Strahlungsgefahr bei Lasereinheiten (nichtionisierend), Bildröhren (ionisierend)

•Verätzungsgefahr bei Anzeigeeinheiten (LCD) und Komponenten mit flüssigem Elektrolyt.

Solche Komponenten dürfen nur von ausgebildetem Fachpersonal mit den vorgeschriebenen Schutzmitteln (u.a. Schutzbrille, Handschuhe) gehandhabt werden.

Maintenance and Repair

The removal of housing parts, shields, etc. exposes energized parts. For this reason the following precautions should be observed:

Maintenance should only be performed by trained personnel in accordance with the applicable regulations. The equipment should be switched off and disconnected from the AC power outlet before any housing parts are removed.

Even if the equipment is disconnected from the power, parts with hazardous charges (e.g. capacitors, picture tubes) must not be touched until they have been properly discharged. Touch hot components (power semiconductors, heat sinks, etc.) only when cooled off.

If maintenance is performed on a unit that is opened and switched on, no uninsulated circuit components and metallic semiconductor housings must be touched neither with your bare hands nor with uninsulated tools.

Certain components pose additional hazards:

•Explosion hazard from lithium batteries, electrolytic capacitors and power semiconductors

•Implosion hazard from evacuated display units

•Radiation hazard from laser units (non-ionizing), picture tubes (ionizing)

•Caustic effect of display units (LCD) and such components containig liquid electrolyte.

Such components should only be handled by trained personnel who are properly protected (e.g. safety goggles, gloves).

VII

WARTUNG / MAINTENANCE

Elektrostatische Entladung (ESD)		Electrostatic Discharge (ESD)
bei Wartung und Reparatur		during Maintenance and Repair
	ATTENTION:	Observe precautions for handling devices sensitive to
		electrostatic discharge!
	ATTENTION:	Respecter les précautions d’usage concernant la mani-
		pulation de composants sensibles à l’électricité statique!
	ACHTUNG:	Vorsichtsmassnahmen bei Handhabung elektrostatisch
		entladungsgefährdeter Bauelemente beachten!

Viele ICs und andere Halbleiter sind empfindlich gegen elektrostatische Entladung (ESD). Unfachgerechte Behandlung von Baugruppen mit solchen Komponenten bei Wartung und Reparatur kann deren Lebensdauer drastisch vermindern.

Bei der Handhabung der ESD-empfindlichen Komponenten sind u.a. folgende Regeln zu beachten:

•ESD-empfindliche Komponenten dürfen ausschliesslich in dafür bestimmten und bezeichneten Verpackungen gelagert und transportiert werden.

•Unverpackte, ESD-empfindliche Komponenten dürfen nur in dafür eingerichteten Schutzzonen (EPA, z.B. Gebiet für Feldservice, Reparaturoder Serviceplatz) gehandhabt und nur von Personen berührt werden, die durch ein Handgelenkband mit Seriewiderstand mit dem Massepotential des Reparaturoder Serviceplatzes verbunden sind. Das gewartete Gerät wie auch Werkzeug, Hilfsmittel, EPAtaugliche (elektrisch halbleitende) Arbeits-, Ablageund Bodenmatten müssen ebenfalls mit diesem Potential verbunden sein.

•Die Anschlüsse der ESD-empfindlichen Komponenten dürfen unkontrolliert weder mit elektrostatisch aufladbaren (Gefahr von Spannungsdurchschlag), noch mit metallischen Oberflächen (Schockentladungsgefahr) in Berührung kommen.

•Um undefinierte transiente Beanspruchung der Komponenten und deren eventuelle Beschädigung durch unerlaubte Spannung oder Ausgleichsströme zu vermeiden, dürfen elektrische Verbindungen nur am abgeschalteten Gerät und nach dem Abbau allfälliger Kondensatorladungen hergestellt oder getrennt werden.

Many ICs and semiconductors are sensitive to electrostatic discharge (ESD). The life of components containing such elements can be drastically reduced by improper handling during maintenance and repair work.

Please observe the following rules when handling ESD sensitive components:

•ESD sensitive components should only be stored and transported in the packing material specifically provided for this purpose.

•Unpacked ESD sensitive components should only be handled in ESD protected areas (EPA, e.g. area for field service, repair or service bench) and only be touched by persons who wear a wristlet that is connected to the ground potential of the repair or service bench by a series resistor. The equipment to be repaired or serviced and all tools, aids, as well as electrically semiconducting work, storage and floor mats should also be connected to this ground potential.

•The terminals of ESD sensitive components must not come in uncontrolled contact with electrostatically chargeable (voltage puncture) or metallic surfaces (discharge shock hazard).

•To prevent undefined transient stress of the components and possible damage due to inadmissible voltages or compensation currents, electrical connections should only be established or separated when the equipment is switched off and after any capacitor charges have decayed.

VIII

WARTUNG / MAINTENANCE

SMD-Bauelemente

SMD Components

Der Austausch von SMD-Bauelementen ist ausschliesslich geübten Fachleuten vorbehalten. Für verwüstete Platinen können keine Ersatzansprüche geltend gemacht werden. Beispiele für korrekte und falsche SMDLötverbindungen in der Abbildung weiter unten.

Bei Studer werden keine handelsüblichen SMD-Teile bewirtschaftet. Für Reparaturen sind die notwendigen Bauteile lokal zu beschaffen. Die Spezifikationen von Spezialbauteilen finden Sie in der Serviceanleitung.

SMDs should only be replaced by skilled specialists. No warranty claims will be accepted for circuit boards that have been ruined. Proper and improper SMD soldering joints are depicted below.

Studer does not keep any commercially available SMDs in stock. For repair the corresponding devices should be purchased locally. The specifications of special components can be found in the service manual.

IX

EMV / EMC

Störstrahlung und Störfestigkeit

Das Gerät entspricht den Schutzanforderungen auf dem Gebiet elektromagnetischer Phänomene, wie u.a. in den Richtlinien 89/336/EWG und FCC, Part 15, aufgeführt:

1.Vom Gerät erzeugte elektromagnetische Strahlung ist soweit begrenzt, dass bestimmungsgemässer Betrieb anderer Geräte und Systeme möglich ist.

2.Das Gerät weist eine angemessene Festigkeit gegen elektromagnetische Störungen auf, so dass sein bestimmungsgemässer Betrieb möglich ist.

Das Gerät wurde getestet und erfüllt die Bedingungen der im Kapitel „Technische Daten“ aufgeführten EMV-Standards. Die Limiten dieser Standards gewährleisten mit angemessener Wahrscheinlichkeit sowohl den Schutz der Umgebung wie auch entsprechende Störfestigkeit des Gerätes. Absolute Garantie, dass keine unerlaubte elektromagnetische Beeinträchtigung während des Betriebes entsteht, ist jedoch nicht gegeben.

Um die Wahrscheinlichkeit solcher Beeinträchtigung weitgehend auszuschliessen, sind u.a. folgende Massnahmen zu beachten:

•Installieren Sie das Gerät gemäss den Angaben in der Betriebsanleitung, und verwenden Sie das mitgelieferte Zubehör.

•Verwenden Sie im System und in der Umgebung, in denen das Gerät eingesetzt ist, nur Komponenten (Anlagen, Geräte), die ihrerseits die Anforderungen der obenerwähnten Standards erfüllen.

•Sehen Sie ein Erdungskonzept des Systems vor, das sowohl die Sicherheitsanforderungen (die Erdung der Geräte gemäss Schutzklasse I mit einem Schutzleiter muss gewährleistet sein), wie auch die EMV-Belange berücksichtigt. Bei der Entscheidung zwischen sternoder flächenförmiger bzw. kombinierter Erdung sind Vorund Nachteile gegeneinander abzuwägen.

•Benutzen Sie abgeschirmte Kabel, wo vorgesehen. Achten Sie auf einwandfreie, grossflächige, korrosionsbeständige Verbindung der Abschirmung zum entsprechenden Steckeranschluss und dessen Gehäuse. Beachten Sie, dass eine nur an einem Ende angeschlossene Kabelabschirmung als Sendebzw. Empfangsantenne wirken kann (z.B. bei wirksamer Kabellänge von 5 m oberhalb von 10 MHz), und dass die Flanken digitaler Kommunikationssignale hochfrequente Aussendungen verursachen (z.B. LSoder HC-Logik bis 30 MHz).

•Vermeiden Sie Bildung von Masseschleifen oder vermindern Sie deren unerwünschte Auswirkung, indem Sie deren Fläche möglichst klein halten und den darin fliessenden Strom durch Einfügen einer Impedanz (z.B. Gleichtaktdrossel) reduzieren.

Electromagnetic Compatibility

The equipment conforms to the protection requirements relevant to electromagnetic phenomena that are listed in the guidelines 89/336/EC and FCC, part 15.

1.The electromagnetic interference generated by the equipment is limited in such a way that other equipment and systems can be operated normally.

2.The equipment is adequately protected against electromagnetic interference so that it can operate cor-

rectly.

The unit has been tested and conforms to the EMC standards applicable to residential, commercial and light industry, as listed in the section „Technical Data“ . The limits of these standards reasonably ensure protection of the environment and corresponding noise immunity of the equipment. However, it is not absolutely warranted that the equipment will not be adversely affected by electromagnetic interference during operation.

To minimize the probability of electromagnetic interference as far as possible, the following recommendations should be followed:

•Install the equipment in accordance with the operating instructions. Use the supplied accessories.

•In the system and in the vicinity where the equipment is installed, use only components (systems, equipment) that also fulfill the above EMC standards.

•Use a system grounding concept that satisfies the safety requirements (protection class I equipment must be connected with a protective ground conductor) that also takes into consideration the EMC requirements. When deciding between radial, surface or combined grounding, the advantages and disadvantages should be carefully evaluated in each case.

•Use shielded cables where shielding is specified. The connection of the shield to the corresponding connector terminal or housing should have a large surface and be corrosion-proof. Please note that a cable

shield connected only single-ended can act as a transmitting or receiving antenna (e.g. with an effective cable length of 5 m, the frequency is above 10 MHz) and that the edges of the digital communication signals cause high-frequency radiation (e.g. LS or HC logic up to 30 MHz).

•Avoid ground loops or reduce their adverse effects by keeping the loop surface as small as possible, and reduce the noise current flowing through the loop by inserting an additional impedance (e.g. commonmode rejection choke).

X

Konformitätserklärungen / Declarations of conformity

Class A Equipment - FCC Notice

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide a reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residen-

tial area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense.

Caution:

Any changes or modifications not expressly approved by the manufacturer could void the user's authority to operate the equipment. Also refer to relevant information in this manual.

CE-Konformitätserklärung

Der Hersteller,

Studer Professional Audio AG, CH-8105 Regensdorf,

erklärt in eigener Verantwortung, dass das Produkt

Studer 928, Mischpult,

(ab Serie-Nr. 1001),

auf das sich diese Erklärung bezieht, entsprechend den Bestimmungen der EU-Richtlinien und Ergänzungen

•Elektromagnetische Verträglichkeit (EMV): 89/336/EWG + 92/31/EWG + 93/68/EWG

•Niederspannung: 73/23/EWG + 93/68/EWG

mit den folgenden Normen und normativen Dokumenten übereinstimmt:

•Sicherheit:

Schutzklasse 1, EN 60950:1992 + A1/A2:1993

•EMV:

EN 55103-1/-2:1996, elektromagnetische Umgebungen E2 und E4

Regensdorf, 28. Februar 1997

B. Hochstrasser, Geschäftsleiter

P. Fiala, Leiter QS

CE Declaration of Conformity

The manufacturer,

Studer Professional Audio AG, CH-8105 Regensdorf,

declares under his sole responsibility that the product

Studer 928, Mixing Console, (on from serial No. 1001),

to which this declaration relates, according to following regulations of EU directives and amendments

•Electromagnetic Compatibility (EMC): 89/336/EEC + 92/31/EEC + 93/68/EEC

•Low Voltage (LVD): 73/23/EEC + 93/68/EEC

is in conformity with the following standards or other normative documents:

•Safety:

Class 1, EN 60950:1992 + A1/A2:1993

•EMC:

EN 55103-1/-2:1996, electromagnetic environments E2 and E4

Regensdorf, February 28, 1997

B. Hochstrasser, Managing director

P. Fiala, Manager QA

XI

928 Mixing Console

CONTENTS

1 General ..........................................................................			E1/1
1.1	Utilization for the purpose intended .............................		E1/2
1.2	First steps .....................................................................		E1/2
	1.2.1	Unpacking and inspection ........................................	E1/2
	1.2.2	Installation ...............................................................	E1/2
	1.2.3	Adjustments, repair ..................................................	E1/4
	1.2.4	Accessories, options .................................................	E1/4
1.3	Specifications ...............................................................		E1/5

Edition: 07.02.01

Contents E 1

928 Mixing Console

E 1 Contents

Edition: 07.02.01

928 Mixing Console

1 GENERAL

The Studer 928 console features a modular 30 mm concept with mechanical frames for 12 or 16 units. This way, different size consoles can be built; the maximum would be 96 input units. Both mono and stereo input units are available. The standard configuration contains 8 mono groups, 2 stereo masters, 6 mono and 2 stereo AUX channels, and 2 monitor modules for studio and control room monitoring.

Functionality of the console is very high. N-1 circuits, direct outputs from every input stage, a sophisticated EQ stage, and a high number of AUX channels, limiters in each group and master stage, and dedicated on-air switching features are normally found only in much more expensive constructions.

The gain control is effected via VCAs in all stages which allow the formation of VCA groups. In every input unit the VCA can be locked to one of four VCA groups, and the group master fader is a linear fader in the monitor module.

To cope with special customer requirements, the meter bridge is able to house all Studer 170 mm units. In addition, Studer Eurocards can be installed in the lower chassis.

No automation is provided in the concept.

The main applications of the console comprise:

∙Live transmission in radio and TV

∙Recording

∙Theatre and Opera

∙Sound reinforcement

∙OB van applications

This development shows the Studer standard of quality the audio world is used to see in our mixing consoles. Studer transformers are used at inputs and outputs, gold contacts for all audio switches, and high quality VCAs to maintain Studer’s standard of “good sound”.

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General E 1/1

928 Mixing Console

1.1Utilization for the purpose intended

The Studer 928 mixing console is intended for professional use.

It is presumed that the unit is operated only by trained personnel. Servicing is reserved to skilled technicians.

The electrical connections may be connected only to the voltages and signals designated in this manual.

1.2First steps

1.2.1 Unpacking and inspection

Your new mixing console is shipped in a special packing which protects the units against mechanical shock during transit. Care should be exercised when unpacking so that the surfaces do not get marred. Verify that the content of the packing agrees with the items listed on the enclosed shipping list.

Check the condition of the equipment for signs of shipping damage. If there should be any complaints you should immediately notify the forwarding agent and your nearest Studer distributor.

Please retain the original packing material because it offers the best protection in case your equipment ever needs to be transported.

1.2.2 Installation

The power supply units are auto-ranging; therefore no voltage selector must be adjusted before connecting them to the mains.

General precautions: Do not use the units in conditions of excessive heat or cold, near any source of moisture, in excessively humid environments, or in positions where they are likely to be subjected to vibration or dust. Do not use any liquids to clean the exterior of the units. A soft, dry cloth or brush

will usually do.

Ventilation/rack mounting: When installing the power supply unit in a rack or any other location, make sure that there is adequate ventilation. The unit should be situ- ated so that its location or position does not interfere with its proper

ventilation. Please refer to the drawing below.

If the power supply unit is rack mounted, the feet may be removed; these may be unscrewed from the outside – do not open the case.

Air flow

Fan

Air flow

Supply unit, versions 1.918.210.00...211.81

E 1/2 General

Air flow

Edition: 07.02.01

928 Mixing Console

Air flow

	Supply unit,
	version 1.918.213.00	Air flow
Power connection:	The attached female IEC 320/C13 mains cable socket has to be con-
	nected to an appropriate mains cable by a trained technician, respect-
	ing your local regulations. Refer to the “Installation, Operation, and
	Waste Disposal” section at the beginning of this manual.
	Maintenance work inside the units must be performed by a trained
	technician.
Earthing:	This equipment must be earthed, due to the mains input filter network
	being connected to the mains earth.
	Some consideration should be given to the earthing arrangement of

the system at the center of which is the console and the power supply unit(s). The console chassis is earthed to the mains earth via the power supply. If the power supply is rack-mounted care should be taken to avoid any possible “ground loops” in the system; this would cause audible hum to be introduced to an otherwise clean audio signal. Ground loops may occur where signal processing equipment, patched to the console, has its signal earth commoned to the equipment chassis. The ground loop is formed if this chassis and the power supply chassis are in electrical contact through fixing rails that they share in the rack.

Tip-over protection: The console must be secured against tipping-over when a weight is placed on the front rail of the console. For this purpose a bracket is fixed to the bottom side of each console foot (3 countersunk-head chipboard screws each). These brackets must then be screwed to the floor with 3 pan-head chipboard screws each; refer to the drawing below.

pan-head chipboard screws

(3 pcs.) 5×30

Cable duct

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General E 1/3

928 Mixing Console

1.2.3 Adjustments, repair

Danger:	All internal adjustments as well as repair work on this product are to
	be performed by skilled technicians!
Replacing the primary fuse:	Supply unit, versions 1.918.210.00...211.81:
	Switch the unit off, remove the mains lead plug from the mains supply
	socket and then from the IEC type mains connector on the unit. The
	fuse is located in the fuse holder contained in the IEC type mains con-
	nector.
	Use only an F 8 A H/250 V fuse.
	Supply unit, version 1.918.213.00:
	The primary fuse is located inside the power supply unit and cannot
	be changed. In case of failure, the complete supply unit must be re-
	placed. Please ask your nearest Studer representative.

1.2.4 Accessories, options

Accessories shipped with the 928 console:		(Set: order No. 1.928.096.00)
5	Circlips, 2.3 mm		Order No. 24.16.3023
1	Rotary knob, grey, Ø 10 mm		Order No. 42.01.0203
1	Cap, dark grey, for button Ø 10 mm		Order No. 42.01.0251
5	Rotary knobs, dark grey, Ø 11 mm		Order No. 42.01.1200
5	Rotary knobs, red, Ø 11 mm		Order No. 42.01.1202
5	Rotary knobs, yellow, Ø 11 mm		Order No. 42.01.1204
5	Rotary knobs, green, Ø 11 mm		Order No. 42.01.1205
5	Rotary knobs, blue, Ø 11 mm		Order No. 42.01.1206
5	Rotary knobs, bright grey, Ø 11 mm		Order No. 42.01.1208
1	Rotary knob, dark grey, Ø 15 mm		Order No. 42.01.1220
1	Rotary knob, bright grey, Ø 15 mm		Order No. 42.01.1228
5	Rotary knobs, lower, dark grey, Ø 15 mm		Order No. 42.01.1240
2	TRS plugs		Order No. 54.02.0601
2	Cap, red		Order No. 55.15.0912
2	Cap, yellow		Order No. 55.15.0914
2	Cap, green		Order No. 55.15.0915
1	Allen screwdriver, short, size 2		Order No. 98.00.0612
1	Hexagonal screwdriver, size 2		Order No. 98.00.2022
1	Hexagonal key, size 2		Order No. 98.00.2405
1	Hexagonal key, size 2.5		Order No. 98.00.2406
5	Oval-head screws, M3×8, w. washer		Order No. 1.010.022.21
6	Fader coupling bridges, 42 mm		Order No. 1.911.000.07
2	Fader knobs (P+G), red		Order No. 1.911.000.42
2	Fader knobs (P+G), orange		Order No. 1.911.000.43
2	Fader knobs (P+G), yellow		Order No. 1.911.000.44
2	Fader knobs (P+G), green		Order No. 1.911.000.45
2	Fader knobs (P+G), blue		Order No. 1.911.000.46
2	Fader knobs (P+G), grey		Order No. 1.911.000.48
2	Fader knobs (P+G), white		Order No. 1.911.000.49
2	Module extractors		Order No. 1.912.000.06

E 1/4 General

Edition: 07.02.01

928 Mixing Console

1.3

Specifications

General

Voltage specification dBu:

0 dBu 0.775 V

Channel input faders and master faders

are set to 0 dB mark.

Line outputs are terminated with 600 Ω.

External sources have a source impedance

of < 200 Ω.

All data are valid within the frequency band

from 31.5 Hz...16 kHz.

PPM version: line level +6 dBu

VU version: nominal output level 0 VU = +4 dBu

Levels

Microphone input sensitivity:

–71...+10 dBu

Line input sensitivity:

+6 dBu ±14 dB

Level at insert points and N–1/direct outputs:

+6 dBu

Output level:

+6 dBu, adjustable

Monitor level (balanced, unloaded):

+6...+15 dBu

Common mode rejection

Microphone input: Uin = 0 dBu;

@ 15 kHz >50 dB

V = 0 dB; Fine = min

@ 50 Hz >75 dB

Line input:

with transformer

@ 50 Hz...15 kHz >50 dB

without transformer

@ 50 Hz...15 kHz >46 dB

Impedances

Microphone input:

>1.6 kΩ, balanced and floating

(w. transformer)

Line/tape input:

>10 kΩ, electronically balanced

(transformer optional)

Source impedance of line outputs:

<40 Ω

Master outputs

è balanced/floating (w. transformer)

All other outpus

è electronically balanced

Frequency response

Filters switched off:

0.5 dB

–3 dB points, filter switched off:

approx. 4.5 Hz/40 kHz

(continuously decreasing outside this range)

Bass cut (18 dB/oct.)

–3 dB @ 75 Hz

High frequency equalizer,

1 kHz...16 kHz:

15 dB

High-mid equalizer,

500 Hz...8 kHz:

15 dB

Low-mid Equalizer,

125 Hz...2 kHz:

15 dB

Low frequency equalizer,

32 Hz...500 Hz:

15 dB

Overload margin

Microphone input:

Max. level for 1% 3rd harmonic @ 31.5 Hz:

+3 dBu; Pos. +10

Line input:

Max. level for 1% 2nd harmonic @ 31.5 Hz:

+24 dBu

Fine adjust 0 dB

Before channel fader (THD = 1%):

20 dB

Before master fader (THD = 1%):

20 dB

Max. line output level:

RL = 300 Ω;

+23.5 dBu

- with transformer:

- without transformer:

+23 dBu

Edition: 07.02.01

General E 1/5

928 Mixing Console

Unweighted noise voltage,	according to IEC 468-2 (DIN 45405)
Microphone	Equivalent input noise for 23 kHz bandwidth,
	termination 200 Ω:	< –126 dBu
Signal-to-noise ratio	PPM version, relative to line level (+6 dBu)
	VU version, relative to peak output level (+6 VU	+10 dBu)
	On master output, master fader closed:	> 95 dB
	One channel, input and master faders at 0 dB mark, unity gain;
	- Filters off:	> 93 dB
	- Filters on, linear:	> 92 dB
	11 channels, all faders at 0 dB mark, unity gain;
	- Filters off:	> 85 dB
	- Filters on, linear:	> 83 dB
Harmonic ratio	PPM version, measured with line level +6 dBu;
	VU version, measured with nominal output level 0 VU, or peak output
	level +6 VU;
	unity gain, 31.5 Hz...16 kHz:	70 dB
Crosstalk attenuation	Channel to channel,
	- without panorama potentiometer	>80 dB
	- with panorama potentiometer	>70 dB
	Channel bus selector switched off:	>90 dB
	Fader attenuation, input	>100 dB
	Fader attenuation, output	>90 dB
Power supply	100...240 V, 50/60 Hz
	Power consumption (Studer 928 32/8/4)	approx. 400 VA
Note:	Depending on the application, the on-air mixing consoles can have
	different configurations. For this reason the abovementioned values
	are applicable only to a typical configuration; in an individual case,
	the values may differ.

We reserve the right to make changes as technological progress may warrant.

E 1/6 General

Edition: 07.02.01

928 Mixing Console

Dimensions (console) in mm:

					12-module				16-module
					base frame				base frame
47				366				488						47

Optional Eurocard rack	Optional Eurocard rack	180	1040
			780
Cable duct	Cable duct	Cable duct	625

640

950

Dimensions (supply unit, versions 1.918.210.00...211.81) in mm:

88 mm

(3½" / 2U)

“A”

	Front view	View “A”
	15...20	195
	480 mm (19")	144
POWER	“B”
	+48V +5V	Fan
	+15V
10	Rear view	View “B”
DC out Link to 2nd PS
CONSOLE LINK
	MAINS

155

120

(155)

Edition: 08.02.01

General E 1/7

928 Mixing Console

Dimensions (supply unit, version 1.918.213.00) in mm:

mm	/ 2U)
88	(3½"

Front view

View “A”

15...20	356	40
480 mm (19")		305
POWER
“A”

A ARM +48 +15V –15V +5V

	10
DC out Link to 2nd PS				Rear view

CONSOLE LINK

MA NS

430

928 console cross section:

170

582

Headphones

jack

Optional

Eurocard rack

Cable

duct

E 1/8 General

Edition: 07.02.01

928 Mixing Console

CONTENTS

2 Operation ......................................................................		E2/1
2.1	Mono input unit ...........................................................	E2/1
2.2	Stereo input unit ..........................................................	E2/5
2.3	Mono group unit ..........................................................	E2/9
2.4	Master unit A/B ..........................................................	E2/12
2.5	CR Monitor unit .........................................................	E2/14
2.6	Studio Monitor unit ....................................................	E2/16

Edition: 07.02.01

Contents E 2

928 Mixing Console

2 OPERATION

2.1 Mono input unit

1.928.220

	[1]
	[2]
[3]	[4]
[5]	[6]
	[7]
	[8]
	[9]
[10]	[11]
[12]
	[13]
	[14]
	[15]
[16]
	[18]
[17]
	[19]
	AN TO GROU S
	PAN
	[20]
	[21]
	[22]
	[23]
	[24]
[26]	[25]

[1]MASTER ΣA, ΣB

Keys for routing the audio signal to the stereo MASTER busses.

[2]GROUP 1...8

Keys for routing the audio signal to the GROUP busses.

[3]TB DIR. OUT

Talk back, momentary pushbutton for talking via the command microphone to the electronically balanced Direct Output.

[4]DIR. OUT/N–1

Key to select N–1 mode (“mix-minus” mode) for the Direct Output. In this operating mode all selected sources except the channel’s own modulation are audible.

There are two N–1 busses in the console: The N–1 ΣA bus, and the

N–1/ bus. The N–1 bus carries a mono mix of the ΣA mix. To provide a mix-minus signal at the direct output using the ΣA mix, the ΣA and the N–1 keys must be pressed.

If the N–1 key is pressed and the ΣA is released, the bus is used as the source of the mix-minus signal. The N–1/ bus carries a mix from all the input modules which have their N–1 key but not their ΣA keyspressed.

Typical application: Direct transmissions or telephone recordings, if the concerned channel is used as a feedback channel to an outside commentator.

The direct output can be jumper-selected to be preor after-fader (refer to section 3.1.1).

[5]48 V

Key for activating the 48 V phantom power for the transformer-bal- anced MICrophone input. If phantom powering is active, the key is illuminated. If the MIC2 option is installed (i.e. 2nd microphone input), the phantom power is applied to both microphone inputs simultaneously if the 48 V key is pressed.

[6]~

Key for selecting the test generator input. If selected, the key is illuminated; a signal with a fixed level and the frequency selected in the

TEST GEN section of the CR Monitor unit is fed into the input.

If the ~ key is released, the LINE or the MIC input is selected, depending on the LINE key [7].

Note: The test generator input is replaced by the MIC2 input if the corresponding option is installed; in this case, no test generator signal is available, but a second microphone can be connected.

Edition: 07.02.01

Operation E 2/1

928 Mixing Console
		[7]	LINE
			Key for selecting the electronically balanced line input (input trans-
			former optional). Input sensitivity adjustable in a ±15 dB range with
	[1]		potentiometer LINE [9].
			If the LINE key is released, the transformer-balanced MICrophone in-
	[2]		put is selected, and the key is dark.
[3]	[4]	[8]	MIC
[5]	[6]		Gain setting for the MIC input.
	[7]		Ring: Coarse gain setting in 10 dB steps, –10...+60 dB.
	[8]		Knob: Additional fine gain adjustment in a range of ±10 dB.
	[9]	[9]	LINE
[10]	[11]		Fine adjustment of the LINE input gain. Adjustment range ±15 dB, with
			detent in calibrated center position.
		[10]	Ø
[12]			Phase inversion switch. If pressed, the phase of the input signal is in-
			verted, and the key is illuminated.
	[13]
		[11]	Key for activating the high-pass filter (turnover frequency 75 Hz, slope
	[14]
			18 dB/oct.). If pressed, the filter is active, and the key is illuminated.
	[15]
[16]		[12]	HF, HMF, LMF, LF
			Semi-parametric four-band equalizer, activated by the EQ key [14].
			HF, LF: Shelving treble/bass filter. The turnover frequencies are adjust-
			able with the outer ring (1...16 kHz or 30...500 Hz, resp.); boost/cut is
			adjustable with the center knobs up to ±15 dB.
	[18]		HMF: Semi-parametric constant-Q equalizer, Qs of 0.7 or 2 can be
[17]			selected. Center frequency adjustable with the	outer	ring
			(500 Hz...8 kHz), boost/cut adjustable with the center knob up to
			±15 dB.
			HLF: Semi-parametric equalizer as HMF, but the center frequency is
	[19]		adjustable between 120 Hz and 2 kHz.
	PAN TO GROUPS
	PAN	[13]	HI Q
	[20]
			Keys for Q selection of the equalizer's HMF and HLF sections. Key
	[21]		pressed/illuminated: high Q (Q = 2); key released/dark: low Q (Q =
	[22]		0.7).
		[14]	EQ
			Key for inserting (key pressed and illuminated) or bypassing (key re-
	[23]		leased and dark) the equalizer [12], [13].
		[15]	INS
			Electronically balanced insert point. If the INS key is pressed and illu-
	[24]		minated, the signal path is routed via the built-in Bantam patch field,
			else the signal path is routed internally.
			The signal is always available on the INSERT SEND jack socket, re-
[26]	[25]		gardless of the INS key. The insert point can be configured with jump-
			ers to be pre-EQ, post-EQ but pre-fader, or post-fader (refer to section
			3.1.1).
E 2/2	Operation			Edition: 07.02.01

928 Mixing Console

	[1]
	[2]
[3]	[4]
[5]	[6]
	[7]
	[8]
	[9]
[10]	[11]
[12]
	[13]
	[14]
	[15]
[16]
	[18]
[17]
	[19]
	PAN TO GROUPS
	PAN
	[20]
	[21]
	[22]
	[23]
	[24]
[26]	[25]

[16]AUX 7, AUX 8

Outputs to the stereo auxiliary busses 7 and 8. The (preor post-fader) input signal can be mixed to the desired AUX bus with the concentric potentiometers. The small knobs are the level controls, while the outer rings are used as PAN controls.

[17]AUX 1+2, AUX 3+4, AUX 5+6

Outputs to the mono auxiliary busses 1...6. The (preor post-fader) input signal can be mixed to the desired AUX bus with the concentric potentiometers; the knobs are the level controls for the odd-numbered AUX busses (1, 3, 5), the outer rings for the even-numbered AUX busses (2, 4, 6).

[18]PRE

If PRE is pressed, the pre-fader signal is mixed to the AUX bus instead of the post-fader signal, and the key is illuminated.

[19]DIR

Key for inserting the AUX 1 potentiometer into to the direct output or N–1 path (DIR OUT). If this key is pressed, the AUX 1 output is muted.

[20]PAN TO GROUPS

Panorama potentiometer with detent in center position. For positioning the mono input signal within the stereo image of the ΣA and ΣB main mixes (MASTER), regardless whether the adjacent PAN key is pressed or not.

If the PAN key is not pressed, the channel signal is routed in mono to all Groups. If it is pressed (and illuminated), the pan pot splits the signal into left and right outputs which are routed to the oddand evennumbered Groups respectively.

[21]ON

Key for activating the channel with the possibility of external control. The EXT MUTE LED below the key is on if MUTE is externally controlled via the remote input.

[22]CUE

Key to activate the CUE function. If the key is pressed for a short time (less than 0.5 s), the function latches; if the key is pressed for more than 0.5 s, it is used as a momentary pushbutton, and the function will be reset after the key has been released.

If the CUE function is activated while the fader is set to its –∞ position, the AFL/PFL signal is connected to the CUE bus, depending on the AFL/PFL setting made on the CR Monitor Unit. The function will be reset as soon as the fader is moved away from the –∞ position.

[23]LED bargraph with OVL LED

The point to be monitored with the level meter can be selected with jumpers from pre-EQ, post-fader, or direct output/N–1. The meter characteristics can be jumper-selected from PPM or VU. (For jumper settings: refer to section 3.1.1).

The OVL LED monitors pre-EQ, post-EQ, and post-fader; if any of these points reaches a level of 6 dB below clipping, the LED comes on.

Edition: 07.02.01

Operation E 2/3

928 Mixing Console

	[1]
	[2]
[3]	[4]
[5]	[6]
	[7]
	[8]
	[9]
[10]	[11]
[12]
	[13]
	[14]
	[15]
[16]
	[18]
[17]
	[19]
	PAN TO GROUPS
	PAN
	[20]
	[21]
	[22]
	[23]
	[24]
[26]	[25]
E 2/4	Operation

[24]1, 2, 3, 4

Keys for selecting the four VCA group master faders located on the CR Monitor and Studio Monitor Units. The selected group faders are acting on the channel VCA in parallel to the channel fader. If a VCA group master fader is selected, the corresponding key is illuminated.

[25]START ON

Two sets of relay contacts to start/stop external machines are available. These may be set to latching (default) or pulsed operation with jumpers (refer to section 3.1.1). The relays are operative only if the unit's LINE input is selected.

The START ON key works in conjunction with the fader's end switch. The ON key will be illuminated at half intensity if the fader is in its

–∞ position when the ON key is pressed, indicating that the remote start is armed. When the fader is moved up, the start relay is excited and the LED in the ON key is illuminated with full intensity. Alternately, if the fader is moved up before the ON key is activated, the relay is excited as soon as the ON key is pressed.

[27]Fader

Linear Penny & Giles fader with VCA control. The fader is placed immediately after the Mute section, allowing for 10 dB gain at its maximum setting.

Edition: 07.02.01

928 Mixing Console

2.2 Stereo input unit

1.928.250

	[1]
	[2]
[3]	[4]
	[5]
	[6]
	[7]
	[8]
	[9]
	[10]
[11]	[12]
	[13]
	[14]
	[15]
[16]
	[18]
[17]
	[19]
	[20]
	[21]
	[22]
	[23]
[25]	[24]

[1]MASTER ΣA, ΣB

Keys for routing the audio signal to the stereo MASTER busses.

[2]GROUP 1-2...7-8

Keys for routing the audio signal to the GROUP bus pairs.

[3]TB DIR. OUT

“Talk back”, momentary pushbutton for talking via the command microphone to the electronically balanced Direct Output.

[4]DIR. OUT/N–1

Key to select N–1 mode (“mix–minus” mode) for the Direct Output. In this operating mode all selected sources except the channel’s own modulation are audible.

There are two N–1 busses in the console: The N–1 ΣA bus, and the N–1/ bus. The N–1 bus carries a mono mix of the ΣA mix. To provide a mix-minus signal at the direct output using the ΣA mix, the ΣA and the N–1 keys must be pressed.

If the N–1 key is pressed and the ΣA is released, the bus is used as the source of the mix-minus signal. The N–1/ bus carries a mix from all the input modules which have their N–1 key but not their ΣA key pressed.

Typical application: Direct transmissions or telephone recordings, if the concerned channel is used as a feedback channel to an outside commentator.

The direct output can be jumper-selected to be preor post-fader (refer to section 3.1.2).

[5]L, R

Channel selector keys. If both keys are dark, the left and the right input channels are routed to the left and right output channels. If both keys are illuminated, the left and the right input channels are swapped and routed to the right and left output channels, respectively. If either the L or the R key is illuminated, only the left or the right input channel is routed to both output channels.

[6]~

Key for selecting the test generator input. If selected, the key is illuminated; a signal with a fixed level and the frequency selected in the

TEST GEN section of the CR Monitor unit is fed into the input.

If the ~ key is released, the standard LINE input or the second IN2 input is selected, depending on the IN2 key [7].

[7]IN2

Key for selecting from the electronically balanced LINE or IN2 inputs (input transformers optional); if the key is illuminated, the IN2 input is active. Input sensitivity adjustable with potentiometer LINE [9].

[8]LINE

Fine adjustment of the input gain. Adjustment range ±15 dB, with detent in calibrated center position.

Edition: 07.02.01

Operation E 2/5

	928 Mixing Console
			[9]	SPREAD
				Control for adjusting the image width from mono (counterclockwise
				stop position) through normal stereo (detent in center position) to extra
		[1]		wide (clockwise stop position).
		[2]	[10]	SPREAD ON
	[3]	[4]
				Key for activating the SPREAD control [9].
		[5]
		[6]	[11]	Ø
		[7]
		[8]		Phase inversion switch. If pressed, the phase of the right channel is
		[9]		inverted, and the key is illuminated.
		[10]	[12]	Key for activating the high-pass filter (turnover frequency 75 Hz, slope
	[11]	[12]
				18 dB/oct.). If pressed, the filter is active, and the key is illuminated.
			[13]	HF, HMF, LMF, LF
		[13]		Fixed-Q equalizer, activated by the EQ key [14].
				HF, LF: Shelving treble/bass filter. The turnover frequencies are adjust-
				able with the outer ring (1...16 kHz or 30...500 Hz, resp.); boost/cut is
				adjustable with the center knobs up to ±15 dB.
		[14]		HMF: Semi-parametric constant-Q equalizer (Q = 0.7). The center fre-
				quency is adjustable with the outer ring (500 Hz...8 kHz), boost/cut is
		[15]
				adjustable with the center knob up to ±15 dB.
	[16]			HLF: Semi-Parametric equalizer as HMF, but the center frequency is
				adjustable between 120 Hz and 2 kHz.
			[14]	EQ
				Key for inserting (key pressed and illuminated) or bypassing (key re-
		[18]		leased and dark) the equalizer [13].
	[17]
			[15]	INS
				Electronically balanced insert point. If the INS key is pressed and illu-
				minated, the signal path is routed via the built-in Bantam jack field,
				else the signal path is routed internally.
		[19]		The signal is always available on the INSERT SEND jack socket, re-
				gardless of the INS key. The insert point can be configured with jump-
				ers (refer to section 3.1.2) to be pre-EQ or post-EQ.
		[20]	[16]	AUX 7, AUX 8
		[21]
				Outputs to the stereo auxiliary busses 7 and 8. The (preor post-fader)
				stereo input signal can be mixed to the desired AUX bus with the dual
				(ganged) potentiometers.
		[22]
			[17]	AUX 1+2, AUX 3+4, AUX 5+6
				Outputs to the mono auxiliary busses 1...6. The leftand right-channel
				(preor post-fader) input signals are summed to a mono signal and can
		[23]		be mixed to the desired AUX bus with the concentric potentiometers;
				the knobs are the level controls for the odd-numbered AUX busses (1,
				3, 5), the outer rings for the even-numbered AUX busses (2, 4, 6).
	[25]	[24]
	E 2/6	Operation		Edition: 07.02.01