Crest audio CM 2208, CM 2204 User Manual

PROFESSIONAL

POWER AMPLIFIERS

™

OWNER’S MANUAL

Intended to alert the user to the presence of uninsulated “dangerous voltage” within the product’s
enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons.

Intended to alert the user of the presence of important operating and maintenance (servicing)
instructions in the literature accompanying the product.

CAUTION: Risk of electrical shock — DO NOT OPEN!
CAUTION: To reduce the risk of electric shock, do not remove cover. No user serviceable parts inside. Refer

servicing to qualified service personnel.

WARNING: To prevent electrical shock or fire hazard, do not expose this appliance to rain or moisture. Before
using this appliance, read the operating guide for further warnings.

Este símbolo tiene el propósito, de alertar al usuario de la presencia de “(voltaje) peligroso” sin aisla

­miento dentro de la caja del producto y que puede tener una magnitud suficiente como para constituir
riesgo de descarga eléctrica.

Este símbolo tiene el propósito de alertar al usario de la presencia de instruccones importantes sobre la
operación y mantenimiento en la información que viene con el producto.

PRECAUCION: Riesgo de descarga eléctrica ¡NO ABRIR!
PRECAUCION: Para disminuír el riesgo de descarga eléctrica, no abra la cubierta. No hay piezas útiles dentro.

Deje todo mantenimiento en manos del personal técnico cualificado.

ADVERTENCIA: Para evitar descargas eléctricas o peligro de incendio, no deje expuesto a la lluvia o humedad
este aparato Antes de usar este aparato, Iea más advertencias en la guía de operación.

Ce symbole est utilisé dans ce manuel pour indiquer à l’utilisateur la présence d’une tension dangereuse
pouvant être d’amplitude suffisante pour constituer un risque de choc électrique.

Ce symbole est utilisé dans ce manuel pour indiquer à l’utilisateur qu’il ou qu’elle trouvera d’importantes
instructions concernant l’utilisation et l’entretien de l’appareil dans le paragraphe signalé.

ATTENTION: Risques de choc électrique — NE PAS OUVRIR!

ATTENTION: Afin de réduire le risque de choc électrique, ne pas enlever le couvercle. Il ne se trouve à l’intérieur

aucune pièce pouvant être reparée par l’utilisateur. Confiez I’entretien et la réparation de l’appareil à un réparateur
Peavey agréé.

AVERTISSEMENT: Afin de prévenir les risques de décharge électrique ou de feu, n’exposez pas cet appareil à
la pluie ou à l’humidité. Avant d’utiliser cet appareil, lisez attentivement les avertissements supplémentaires de ce
manuel.

Dieses Symbol soll den Anwender vor unisolierten gefährlichen Spannungen innerhalb des Gehäuses
warnen, die von Ausreichender Stärke sind, um einen elektrischen Schlag verursachen zu können.

Dieses Symbol soll den Benutzer auf wichtige Instruktionen in der Bedienungsanleitung aufmerksam
machen, die Handhabung und Wartung des Produkts betreffen.

VORSICHT: Risiko — Elektrischer Schlag! Nicht öffnen!
VORSICHT: Um das Risiko eines elektrischen Schlages zu vermeiden, nicht die Abdeckung enfernen. Es befin

­den sich keine Teile darin, die vom Anwender repariert werden könnten. Reparaturen nur von qualifiziertem
Fachpersonal durchführen lassen.

ACHTUNG: Um einen elektrischen Schlag oder Feuergefahr zu vermeiden, sollte dieses Gerät nicht dem Regen
oder Feuchtigkeit ausgesetzt werden. Vor Inbetriebnahme unbedingt die Bedienungsanleitung lesen.

2

IMPORTANT SAFETY INSTRUCTIONS

WARNING: When using electrical products, basic cautions should always be followed, including the following:

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any of the ventilation openings. Install in accordance with manufacturer’s instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves or other apparatus (including
amplifiers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with
one wider than the other. A grounding type plug has two blades and a third grounding plug. The wide blade or
third prong is provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for
replacement of the obsolete outlet.

10. Protect the power cord from being walked on or pinched, particularly at plugs, convenience receptacles, and the
point they exit from the apparatus.

11. Note for UK only: If the colors of the wires in the mains lead of this unit do not correspond with the terminals in your
plug‚ proceed as follows:

a) The wire that is colored green and yellow must be connected to the terminal that is marked by the letter E‚ the

earth symbol‚ colored green or colored green and yellow.

b) The wire that is colored blue must be connected to the terminal that is marked with the letter N or the color black.
c) The wire that is colored brown must be connected to the terminal that is marked with the letter L or the color red.

12. Only use attachments/accessories provided by the manufacturer.

13. Use only with a cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus. When
a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.

14. Unplug this apparatus during lightning storms or when unused for long periods of time.

15. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged

in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the
apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.

16. Never break off the ground pin. Write for our free booklet “Shock Hazard and Grounding.” Connect only to a power
supply of the type marked on the unit adjacent to the power supply cord.

17. If this product is to be mounted in an equipment rack, rear support should be provided.

18. Exposure to extremely high noise levels may cause a permanent hearing loss. Individuals vary considerably in
susceptibility to noise-induced hearing loss, but nearly everyone will lose some hearing if exposed to sufficiently
intense noise for a sufficient time. The U.S. Government’s Occupational and Health Administration (OSHA) has
specified the following permissible noise level exposures:

Duration Per Day In Hours Sound Level dBA, Slow Response

8 90
6 92
4 95
3 97
2 100
1
1 105

According to OSHA, any exposure in excess of the above permissible limits could result in some hearing loss. Ear plugs or protectors to
the ear canals or over the ears must be worn when operating this amplification system in order to prevent a permanent hearing loss, if
exposure is in excess of the limits as set forth above. To ensure against potentially dangerous exposure to high sound pressure levels, it is
recommended that all persons exposed to equipment capable of producing high sound pressure levels such as this amplification system be
protected by hearing protectors while this unit is in operation.

1

⁄2 102

1

⁄2 110

1

⁄4 or less 115

SAVE THESE INSTRUCTIONS!

xx

3

WICHTIGE SICHERHEITSHINWEISE

ACHTUNG: Beim Einsatz von Elektrogeräten müssen u.a. grundlegende Vorsichtsmaßnahmen befolgt werden:

1. Lesen Sie sich diese Anweisungen durch.

2. Bewahren Sie diese Anweisungen auf.

3. Beachten Sie alle Warnungen.

4. Befolgen Sie alle Anweisungen.

5. Setzen Sie dieses Gerät nicht in der Nähe von Wasser ein.

6. Reinigen Sie es nur mit einem trockenen Tuch.

7. Blockieren Sie keine der Lüftungsöffnungen. Führen Sie die Installation gemäß den Anweisungen des Herstellers durch.

8. Installieren Sie das Gerät nicht neben Wärmequellen wie Heizungen, Heizgeräten, Öfen oder anderen Geräten (auch Verstärkern),
die Wärme erzeugen.

9. Beeinträchtigen Sie nicht die Sicherheitswirkung des gepolten Steckers bzw. des Erdungssteckers. Ein gepolter Stecker weist
zwei Stifte auf, von denen einer breiter ist als der andere. Ein Erdungsstecker weist zwei Stifte und einen dritten Erdungsstift auf.
Der breite Stift bzw. der dritte Stift dient Ihrer Sicherheit. Sollte der beiliegende Stecker nicht in Ihre Steckdose passen, wenden
Sie sich bitte an einen Elektriker, um die ungeeignete Steckdose austauschen zu lassen.

10. Schützen Sie das Netzkabel, sodass niemand darauf tritt oder es geknickt wird, insbesondere an Steckern oder Buchsen und
ihren Austrittsstellen aus dem Gerät.

11. Hinweis – Nur für Großbritannien: Sollte die Farbe der Drähte in der Netzleitung dieses Geräts nicht mit den Klemmen in Ihrem
Stecker übereinstimmen, gehen Sie folgendermaßen vor:

a) Der grün-gelbe Draht muss an die mit E (Symbol für Erde) markierte bzw. grüne oder grün-gelbe Klemme angeschlossen

werden.

b) Der blaue Draht muss an die mit N markierte bzw. schwarze Klemme angeschlossen werden.
c) Der braune Draht muss an die mit L markierte bzw. rote Klemme angeschlossen werden.

12. Verwenden Sie nur die vom Hersteller erhältlichen Zubehörgeräte oder Zubehörteile.

13. Verwenden Sie nur einen Wagen, Stativ, Dreifuß, Träger oder Tisch, der den Angaben des Herstellers entspricht oder zusammen
mit dem Gerät verkauft wurde. Wird ein Wagen verwendet, bewegen Sie den Wagen mit dem darauf befindlichen Gerät besonders
vorsichtig, damit er nicht umkippt und möglicherweise jemand verletzt wird.

14. Trennen Sie das Gerät während eines Gewitters oder während längerer Zeiträume, in denen es nicht benutzt wird, von der
Stromversorgung.

15. Lassen Sie sämtliche Wartungsarbeiten von qualifizierten Kundendiensttechnikern durchführen. Eine Wartung ist erforderlich,
wenn das Gerät in irgendeiner Art beschädigt wurde, etwa wenn das Netzkabel oder der Netzstecker beschädigt wurden,
Flüssigkeit oder Gegenstände in das Gerät gelangt sind, das Gerät Regen oder Feuchtigkeit ausgesetzt wurde, nicht normal
arbeitet oder heruntergefallen ist.

16. Der Erdungsstift darf nie entfernt werden. Auf Wunsch senden wir Ihnen gerne unsere kostenlose Broschüre „Shock Hazard and
Grounding“ (Gefahr durch elektrischen Schlag und Erdung) zu. Schließen Sie nur an die Stromversorgung der Art an, die am
Gerät neben dem Netzkabel angegeben ist.

17. Wenn dieses Produkt in ein Geräte-Rack eingebaut werden soll, muss eine Versorgung über die Rückseite eingerichtet werden.

18. Belastung durch extrem hohe Lärmpegel kann zu dauerhaftem Gehörverlust führen. Die Anfälligkeit für durch Lärm bedingten
Gehörverlust ist von Mensch zu Mensch verschieden, das Gehör wird jedoch bei jedem in gewissem Maße geschädigt, der über
einen bestimmten Zeitraum ausreichend starkem Lärm ausgesetzt ist. Die US-Arbeitsschutzbehörde (Occupational and Health
Administration, OSHA) hat die folgenden zulässigen Pegel für Lärmbelastung festgelegt:

8 90
6 92
4 95
3 97
2 100
1
1 105

Dauer pro Tag in Stunden Geräuschpegel dBA, langsame Reaktion

1

⁄2 102

1

1

⁄2 110

⁄4 oder weniger 115

Laut OSHA kann jede Belastung über den obenstehenden zulässigen Grenzwerten zu einem gewissen Gehörverlust führen. Sollte
die Belastung die obenstehenden Grenzwerte übersteigen, müssen beim Betrieb dieses Verstärkungssystems Ohrenstopfen oder
Schutzvorrichtungen im Gehörgang oder über den Ohren getragen werden, um einen dauerhaften Gehörverlust zu verhindern. Um sich vor
einer möglicherweise gefährlichen Belastung durch hohe Schalldruckpegel zu schützen, wird allen Personen empfohlen, die mit Geräten
arbeiten, die wie dieses Verstärkungssystem hohe Schalldruckpegel erzeugen können, beim Betrieb dieses Geräts einen Gehörschutz zu tra
gen.

BEWAHREN SIE DIESE SICHERHEITSHINWEISE AUF!

4

-

INSTRUCTIONS IMPORTANTES DE SECURITE

ATTENTION: L’utilisation de tout appareil électrique doit être soumise aux precautions d’usage incluant:

1. Lire ces instructions.

2. Gardez ce manuel pour de futures références.

3. Prétez attention aux messages de précautions de ce manuel.

4. Suivez ces instructions.

5. N’utilisez pas cette unité proche de plans d’eau.

6. N’utilisez qu’un tissu sec pour le nettoyage de votre unité.

7. N’obstruez pas les systèmes de refroidissement de votre unité et installez votre unité en fonction des instructions
de ce manuel.

8. Ne positionnez pas votre unité à proximité de toute source de chaleur.

9. Connectez toujours votre unité sur une alimentation munie de prise de terre utilisant le cordon d’alimentation
fourni.

10. Protégez les connecteurs de votre unité et positionnez les cablages pour éviter toutes déconnexions accidentelles.

11. Note pour les Royaumes-Unis: Si les couleurs de connecteurs du cable d’alimentation ne correspond pas au guide
de la prise secteur, procédez comme suit:

a) Le connecteur vert et jaune doit être connectrer au terminal noté E, indiquant la prise de terre ou correspondant

aux couleurs verte ou verte et jaune du guide.

b) Le connecteur Bleu doit être connectrer au terminal noté N, correspondnat à la couleur noire du guide.
c) Le connecteur marron doit être connectrer au terminal noté L, correspondant à la couleur rouge du guide..

12. N’utilisez que des fixations approuvées par le fabriquant.

13. Lors de l’utilsation sur pied ou pole de support, assurez dans le cas de déplacement de l’ensemble enceinte/
support de prévenir tout basculement intempestif de celui-ci.

14. Il est conseillé de déconnecter du secteur votre unité en cas d’orage ou de durée prolongée sans utilisation.

15. Seul un technicien agréé par le fabriquant est à même de réparer/contrôler votre unité. Celle-ci doit être contrôlée si
elle a subit des dommages de manipulation, d’utilisation ou de stockage (humidité,…).

16. Ne déconnectez jamais la prise de terre de votre unité.

17. Si votre unité est destinée a etre montée en rack, des supports arriere doivent etre utilises.

18. Une exposition à de hauts niveaux sonores peut conduire à des dommages de l’écoute irréversibles. La suscep
tibilité au bruit varie considérablement d’un individu à l’autre, mais une large majorité de la population expériencera
une perte de l’écoute après une exposition à une forte puissance sonore pour une durée prolongée. L’organisme de
la santé américaine (OSHA) a produit le guide ci-dessous en rapport à la perte occasionnée:

-

Durée par Jour (heures) Niveau sonore moyen (dBA)

8 90
6 92
4 95
3 97
2 100
1
1 105

D’après les études menées par le OSHA, toute exposition au delà des limites décrites ce-dessus entrainera des pertes de l’écoute chez la
plupart des sujets. Le port de système de protection (casque, oreilette de filtrage,…) doit être observé lors de l’opération cette unité ou des
dommages irréversibles peuvent être occasionnés. Le port de ces systèmes doit être observé par toutes personnes susceptibles d’être expo
sées à des conditions au delà des limites décrites ci-dessus.

1

⁄2 102

1

⁄2 110

1

⁄4 ou inférieur 115

GARDEZ CES INSTRUCTIONS!

-

5

INSTRUCCIONES IMPORTANTES PARA SU SEGURIDAD

CUIDADO: Cuando use productos electrónicos, debe tomar precauciones básicas, incluyendo las siguientes:

1. Lea estas instrucciones.

2. Guarde estas instrucciones.

3. Haga caso de todos los consejos.

4. Siga todas las instrucciones.

5. No usar este aparato cerca del agua.

6. Limpiar solamente con una tela seca.

7. No bloquear ninguna de las salidas de ventilación. Instalar de acuerdo a las instrucciones del fabricante.

8. No instalar cerca de ninguna fuente de calor como radiadores, estufas, hornos u otros aparatos (incluyendo amplificadores)
que produzcan calor.

9. No retire la patilla protectora del enchufe polarizado o de tipo “a Tierra”. Un enchufe polarizado tiene dos puntas, una
de ellas más ancha que la otra. Un enchufe de tipo “a Tierra” tiene dos puntas y una tercera “a Tierra”. La punta ancha (
la tercera ) se proporciona para su seguridad. Si el enchufe proporcionado no encaja en su enchufe de red, consulte a un
electricista para que reemplaze su enchufe obsoleto.

10. Proteja el cable de alimentación para que no sea pisado o pinchado, particularmente en los enchufes, huecos, y los puntos
que salen del aparato.

11. Nota para el Reino Unido solamente: Si los colores de los cables en el enchufe principal de esta unidad no corresponden
con los terminales en su enchufe‚ proceda de la siguiente manera:

a) El cable de color verde y azul debe ser conectado al terminal que está marcado con la letra E‚ el símbolo de Tierra

(earth)‚ coloreado en verde o en verde y amarillo.

b) El cable coloreado en azul debe ser conectado al terminal que está marcado con la letra N o el color negro.
c) El cable coloreado en marrón debe ser conectado al terminal que está marcado con la letra L o el color rojo.

12. Usar solamente añadidos/accesorios proporcionados por el fabricante.

13. Usar solamente un carro, pie, trípode, o soporte especificado por el fabricante, o vendido junto al aparato. Cuando se use
un carro, tenga cuidado al mover el conjunto carro/aparato para evitar que se dañe en un vuelco. No suspenda esta caja de
ninguna manera.

14. Desenchufe este aparato durante tormentas o cuando no sea usado durante largos periodos de tiempo.

15. Para cualquier reparación, acuda a personal de servicio cualificado. Se requieren reparaciones cuando el aparato ha sido
dañado de alguna manera, como cuando el cable de alimentación o el enchufe se han dañado, algún líquido ha sido
derramado o algún objeto ha caído dentro del aparato, el aparato ha sido expuesto a la lluvia o la humedad, no funciona de
manera normal, o ha sufrido una caída.

16. Nunca retire la patilla de Tierra.Escríbanos para obtener nuestro folleto gratuito “Shock Hazard and Grounding” (“Peligro
de Electrocución y Toma a Tierra”). Conecte el aparato sólo a una fuente de alimentación del tipo marcado al lado del cable
de alimentación.

17. Si este producto va a ser enracado con más equipo, use algún tipo de apoyo trasero.

18. La exposición a altos niveles de ruido puede causar una pérdida permanente en la audición. La susceptibilidad a la pérdida
de audición provocada por el ruido varía según la persona, pero casi todo el mundo perderá algo de audición si se expone
a un nivel de ruido suficientemante intenso durante un tiempo determinado. El Departamento para la Salud y para la
Seguridad del Gobierno de los Estados Unidos (OSHA) ha especificado las siguientes exposiciones al ruido permisibles:

Duración por Día en Horas Nivel de Sonido dBA, Respuesta Lenta

8 90
6 92
4 95
3 97
2 100
1
1 105

De acuerdo al OSHA, cualquier exposición que exceda los límites arriba indicados puede producir algún tipo de pérdida en la audición.
Protectores para los canales auditivos o tapones para los oídos deben ser usados cuando se opere con este sistema de sonido para preve
nir una pérdida permanente en la audición, si la exposición excede los límites indicados más arriba. Para protegerse de una exposición a
altos niveles de sonido potencialmente peligrosa, se recomienda que todas las personas expuestas a equipamiento capaz de producir altos
niveles de presión sonora, tales como este sistema de amplificación, se encuentren protegidas por protectores auditivos mientras esta uni
dad esté operando.

1

⁄2 102

1

⁄2 110

1

⁄4 o menos 115

-

-

GUARDE ESTAS INSTRUCCIONES!

6

Introduction

ENGLISH

CM™ Series power amplifiers feature a unique amplification architecture
providing a host of user benefits including simplified operation and use in
multiple applications, as well as unsurpassed sonic quality and flexible power.

Easy to Use

Multiple Uses

Protection Circuits/Safety

ACL™

(Active Clip Limiting, or Voltage limiting)

IGM™

(Instantaneous Gain Modulation, or current limiting)

AUTORAMP

™

The CM 2204-AB (US model)/CM 2204-DV (European model) and CM
2208-AB (US model)/CM 2208-DV (European model) are easy to set up and
operate. Housed in a lightweight-but-rugged 16-gauge steel chassis, multi­load architecture allows low impedance or 70 Volt operation without so
much as flipping a switch. Each channel outputs 220 Watts (70V or 8 Ohms,
or 160 Watts into 4 Ohms) for flexible system configuration, while front-to­side cooling delivers low mains current draw, ensuring efficient operation in
a 2U rack space.

CM Series products comprise four-channel (CM 2204-AB/DV) and eight­channel (CM 2208-AB/DV) units (channels are independent). A host of
applications benefit from the use of multiple channel amplification, including
bars, clubs and restaurants; video conferencing systems; hotels and motels;
industrial installations; and retail stores, among others. One amplifier
for multiple applications provides a cost-effective solution, expansion
opportunities and unparalleled flexibility.

The CM Series has numerous circuit protection features, including:

Automatically reduces gain at the onset of clipping to prevent amplifier and
load damage.

Monitors load current to protect against overloading.

Gradually increases gain when the amplifier is turned on, preventing abrupt
turn-on level.

Other protection features:

Features at a glance:

Short circuit, DC voltage, comprehensive thermal management, current in­rush turn-on/off transient and sub/ultrasonic input.

Some of the protection features are described in more detail later in this
manual but please note that improper use can be dangerous to the user as
well as the unit. These amplifiers are very high-powered and can produce
high voltages and sizable currents. Always use safe operating techniques
when operating these amplifiers but we also encourage you to read this
manual thoroughly.

• 4- or 8-channel power amp systems—220 Watts RMS per channel
(70 Volts)

• Low-Z (4 or 8 Ohms) or 70 Volt output

• Input connectors: balanced three-pin Phoenix

• Output connectors: two-pin Phoenix

• Full range of protection circuits including ACL, IGM and AUTORAMP

• 16-gauge steel chassis

• 2U rack space height

• CM 2204-AB/DV: 34 lbs./35.5 lbs.

CM 2208-AB/DV: 36.5 lbs./38.0 lbs.

• Front-to-side cooling

• Front-panel LED indicators per channel: signal, clip, and protect

• Input and output mating connectors are included

7

Introduction

Unpacking

Mounting

Cooling Requirements

Upon unpacking, inspect the amplifier. If you find any damage, notify your
supplier immediately. Only the consignee may institute a claim with the
carrier for damage incurred during shipping. Be sure to save the carton
and all packing materials. Should you ever need to ship the unit back to
Crest Audio, one of its offices, service centers or the supplier, use only the
original factory packing. If the shipping carton is unavailable, contact Crest
Audio to obtain a replacement.

The CM™ Series power amplifiers will mount in standard 19" racks.

The CM Series power amplifiers use a forced-air cooling system to maintain
a low, even operating temperature. Air is drawn into the amplifier via a
fan located in the front of the unit and courses through the cooling fins of
the heat sink. The air then exits through the sides of the chassis. If the heat
sinks get too hot‚ a sensor circuit will activate the protective muting system
to protect the amplifier. When the internal temperature reaches a safe level‚
the amplifier will automatically return to normal operation. It is important
that both the front and the side of the unit have adequate space to allow
the cooling air to enter and escape. If the amp is rack mounted, do not use
doors or covers on the front of the rack; the intake air must flow without
resistance. If you are using racks with closed backs, make sure that there
is one (1) standard rack space opening for every three mounted power
amplifiers. If not rack mounted‚ allow 6" of clearance on all sides.

8

Operating Precautions

Make sure the mains voltage is correct and is the same as that printed on
the rear of the amplifier. Damage caused by connecting the amplifier to
improper AC voltage is not covered by any warranty.

Note: Always turn off and disconnect the amplifier from mains voltage
before making audio connections. Also, as an extra precaution, turn down
the attenuators before powering up.

It is always a good idea to have the gain controls turned down while
powering up to prevent speaker damage if there is a high signal level at the
inputs. Whether you buy or make them, use good-quality connections, input
cables and speaker cables, along with good soldering technique, to ensure
trouble-free operation. Most intermittent problems are caused by faulty
cables.

Consult the Wire Gauge Chart (below) to determine proper gauges for
various load impedances and cable lengths. Remember that cable impedance
robs amplifier power in two ways: power lost directly to resistance (I2R
loss), and by raising the total load impedance.

W I R E G A U G E C H A R T

Cable Length

(In Feet)

5 18 .79 1.58
16 .50 1.00
14 .31 .62
12 .20 .40
10 .125 .25
10 18 1.58 3.16
16 1.00 2.00
14 .62 1.25
12 .40 .80
10 .25 .50
40 18 8.00 12.60
16 4.00 8.00
14 2.50 5.00
12 1.60 3.20
10 1.00 2.00

8 .625 1.25
80 16 8.00 16.00
14 5.00 10.00
12 3.20 6.40
10 2.00 4.00

Stranded Wire Gauge

(AWG)

Power Loss into

8 Ohms (%)

Power Loss into

4 Ohms (%)

9

Front Panel

1 2 3

1 2 3

(1) Power Indicator

(2) Signal Indicators

(3) Clip Indicators

The green LED indicates that AC power is supplied to the unit and the
power switch is ON.

Green LEDs indicate significant signal presence on that channel output.
The Signal Indicator illuminates only when an output signal is 1 Watt or
higher (at 70V). Therefore, it is possible to have an acceptably strong signal
without the Signal Indicator illuminating.

The Clip Indicator LED illuminates yellow when the CM 2204/CM 2208
experiences excessive voltage or current into the load. When the amplifier

™

output reaches its limits, Active Clip Limiting (ACL

) will attempt to
compress the signal, causing the Clip LED to illuminate momentarily.
An over-current condition is more likely to occur with low impedance

™

speakers. For more information on clipping, see the IGM

and ACL

descriptions on page 7.

Upon continuous clipping, the unit will go into Protect (see # 4 below)
for one second and check the clipping condition. If the unit experiences a
persistent clipping condition, the unit will go into Protect permanently for
that channel, indicated by the Protect LED blinking steadily. In this case, to
bring that channel out of Protect mode, it is necessary to cycle power by
turning the unit OFF and then ON. If the Protect LED continues to blink
after power is restored, it is likely that the channel is damaged and service
to the unit is required.

10

Front Panel

(4) Protect Indicators

4

4

6

6

5

5

Upon powering up the unit, the Protect LEDs illuminate momentarily and
then turn off one channel at a time and then remain off. During normal
operation, an over-current condition can occur if the amplifier is being
overdriven to the point where clipping is continuous or from a short circuit
in the speaker output. The Protect LED will illuminate red when one of
these conditions occurs.

™

The internal temperature of CM

Series amplifiers is 65º celsius. Should
the unit exceed this temperature, the amplifier will go into thermal protect
mode (generally, this would only occur if the internal fan fails). If the
amplifier has a thermal fault condition‚ all LEDs will illuminate. When the
amplifier cools down, the unit will restart automatically.

(5) AC Power Switch

(6) Cooling Air Vent

CM Series power amplifiers have a standard AC switch on the front panel.

Warning: The power switch does not break both sides of the
line and under certain conditions hazardous energy can be present
when the switch is in the OFF position.

The CM Series is designed to operate under extreme conditions. The
front-panel design features a duct that allows air to be drawn in by the fan,
circulated through the removable filter (for cleaning) and finally dispersing
out the sides of the unit. The openings on the front and sides of the unit
should never be blocked. It is recommended that the removable filter be
cleaned with compressed air.

11

Rear Panel

0dB

-6

-

0dB

-6

-

0dB

-6

-

0dB

-6

-

www.crestaudio.com

Crest Audio, Inc.
Fair Lawn, NJ USA

Designed and manufactured in the USA by

:

Outputs
Class 2 Wiring

Inputs

Gain

Ch 4

0dB

x40

Gain

Ch 3

0dB

x40

HPF

Gain

Ch 2

0dB

x40

Gain

Ch 1

0dB

x40

HPF

WARNING:

TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, THIS APPARATUS SHOULD NOT BE EXPOSED TO RAIN OR
MOISTURE AND OBJECTS FILLED WITH LIQUIDS, SUCH AS VASES,
SHOULD NOT BE PLACED ON THIS APPARATUS.

AVIS:

DANS LE BUT DE REDUIRE LES RISQUES D’INCENDIE OU
DE DECHARGE ELECTRIQUE, CET APPREIL NE DOIT PAS ETRE
EXPOSE A LA PLUIE OU A L’HUMIDITE ET AUCUN OBJET REMPLI
DE LIQUIDE, TEL QU’UN VASE, NE DOIT ETRE POSE SUR CELUI-CI.

AVIS:

RISQUE DE CHOC ÉLECTRIQUE-NE PAS OUVRIR

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPE

N

MOUNT IN RACK O NLY.

INSTALLER SUR SUPPO RT DE MONTAGE SEUL EMENT.

220 Watts @ 70.7 V
220 Watts @ 8 Ohms
160 Watts @ 4 Ohms

Output Power per Channel

+

Ch 1

+

Ch 2

+

Ch 3

+

Ch 4

7

7

8

8

(7) AC Mains Power Receptacle

(8) Channel Outputs

This is a standard IEC power connector. An AC mains cord having the
appropriate AC plug and ratings for the intended operating voltage is
included in the carton. The mains cord should be connected to the amplifier
before connecting to a suitable AC outlet.

AC Mains Cord

The mains cord supplied with the unit is a heavy duty‚ three conductor-type
with a conventional 120 VAC plug (230 VAC European) with ground pin.
Never break off the ground pin on any equipment. It is provided for your
safety. If the outlet used does not have a ground pin‚ a suitable grounding
adapter should be used and the third wire should be properly grounded.

NOTE FOR UK ONLY:

If the colors of the wires in the mains lead of this unit do not correspond
with the colored markings identifying terminals in your plug, proceed as
follows: (1) The wire that is colored green and yellow must be connected to
the terminal marked by the letter E, or by the earth symbol, or colored green
or green and yellow. (2) The wire that is colored blue must be connected to
the terminal that is marked with the letter N, or colored black. (3) The wire
that is colored brown must be connected to the terminal that is marked with
the letter L or colored red.

The outputs are two-pin Phoenix connectors. Connect the loudspeaker sys­tem to the respective positive (+) and ground (-) terminals as indicated on
the unit. An exception is when the unit is in Bridged Mode, whereupon a
speaker is connected to two positive terminals on the outputs of two chan
nels.

12

-

Rear Panel

Inputs

Ga

i

n

C

h

4

0dB

x

4

0

0d
B

-6

0d
B

-6

Inputs

Ga

i

n

C

h

4

0dB

x

4

0

0dB

-6

-

0dB

-6

-

0dB

-6

-

0dB

-6

-

www.crestaudio.com

Crest Audio, Inc.
Fair Lawn, NJ USA

Designed and manufactured in the USA by

:

Outputs
Class 2 Wiring

Inputs

Gain

Ch 4

0dB

x40

Gain

Ch 3

0dB

x40

HPF

Gain

Ch 2

0dB

x40

Gain

Ch 1

0dB

x40

HPF

WARNING:

TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, THIS APPARATUS SHOULD NOT BE EXPOSED TO RAIN OR
MOISTURE AND OBJECTS FILLED WITH LIQUIDS, SUCH AS VASES,
SHOULD NOT BE PLACED ON THIS APPARATUS.

AVIS:

DANS LE BUT DE REDUIRE LES RISQUES D’INCENDIE OU
DE DECHARGE ELECTRIQUE, CET APPREIL NE DOIT PAS ETRE
EXPOSE A LA PLUIE OU A L’HUMIDITE ET AUCUN OBJET REMPLI
DE LIQUIDE, TEL QU’UN VASE, NE DOIT ETRE POSE SUR CELUI-CI.

AVIS:

RISQUE DE CHOC ÉLECTRIQUE-NE PAS OUVRIR

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

MOUNT IN RACK O NLY.

INSTALLER SUR SUPPO RT DE MONTAGE SEUL EMENT.

220 Watts @ 70.7 V
220 Watts @ 8 Ohms
160 Watts @ 4 Ohms

Output Power per Channel

+

Ch 1

+

Ch 2

+

Ch 3

+

Ch 4

9

9

(9) Channel Inputs

The inputs are balanced, three-pin Phoenix connectors. Connect the
incoming signals to the respective positive (+), negative (-) and ground ( )
terminals as indicated on the unit. Channel input sensitivity is 0dBu (0.775V)
when the 0dB gain setting is selected. This equates to a gain of 90.3x. Gain
can also be decreased to x40 with the gain setting switch (see # 12 Gain
Select). If using bridged, see the Bridged Mode section.

Input Connections

The Phoenix connectors are wired as: Pin 1 is positive; Pin 2 is negative;
and Pin 3 is chassis ground. Normally balanced inputs are wired using
two-conductor shielded cable as shown in the following diagram. For un­balanced (single-ended) inputs‚ the single conductor is wired to Pin 1 and
the shield is connected to Pins 2 & 3 as shown in the following diagram.

Balanced Unbalanced

13

Rear Panel

0dB

-6

-

0dB

-6

-

0dB

-6

-

0dB

-6

-

www.crestaudio.com

Crest Audio, Inc.
Fair Lawn, NJ USA

Designed and manufactured in the USA by

:

Outputs
Class 2 Wiring

Inputs

Gain

Ch 4

0dB

x40

Gain

Ch 3

0dB

x40

HPF

Gain

Ch 2

0dB

x40

Gain

Ch 1

0dB

x40

HPF

WARNING:

TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, THIS APPARATUS SHOULD NOT BE EXPOSED TO RAIN OR
MOISTURE AND OBJECTS FILLED WITH LIQUIDS, SUCH AS VASES,
SHOULD NOT BE PLACED ON THIS APPARATUS.

AVIS:

DANS LE BUT DE REDUIRE LES RISQUES D’INCENDIE OU
DE DECHARGE ELECTRIQUE, CET APPREIL NE DOIT PAS ETRE
EXPOSE A LA PLUIE OU A L’HUMIDITE ET AUCUN OBJET REMPLI
DE LIQUIDE, TEL QU’UN VASE, NE DOIT ETRE POSE SUR CELUI-CI.

AVIS:

RISQUE DE CHOC ÉLECTRIQUE-NE PAS OUVRIR

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

MOUNT IN RACK O NLY.

INSTALLER SUR SUPPO RT DE MONTAGE SEUL EMENT.

220 Watts @ 70.7 V
220 Watts @ 8 Ohms
160 Watts @ 4 Ohms

Output Power per Channel

+

Ch

1

+

Ch

2

+

Ch

3

+

Ch

4

10

11

12

10

11

12

(10) High-Pass Filter

(11) Stepped Attenuators

(12) Gain Select

(13) Circuit Breaker

This two-position switch provides enabling or bypass of a high-pass filter,
which is available on each channel input. In the top position (enabled), the
high-pass filter cutoff is 70 Hz. In the bottom position (disabled), the input
frequency range is extended down to 1 Hz. The top and bottom positions
of the high-pass filter are indicated on the unit by a sloped line and a flat
line, respectively.

Each channel input features a 21-position stepped attenuator ranging from
negative infinity to 0 dB. The “halfway” position of the stepped attenuator is

-6 dB, as indicated on the unit.

An individual Gain Select is available on each channel input. This two­position switch can be set at 0 dB in the bottom position and x40 in the
top position.

If the circuit breaker pops, turn the unit OFF and let sit for one minute and
then turn back ON. If the circuit breaker pops a second time, the unit may
be damaged and should be returned to a Crest Audio dealer for servicing.

14

Bridged Mode

Wire Connections

+ input

GND inpu

t

- input

0dB

-6

-

0dB

-6

-

Inputs

Gain

Ch 2

0dB

x40

Gain

Ch 1

0dB

x40

HPF

TO REDUCE THE RISK OF FIRE OR ELECTRIC

AP

PARATUS SHOULD NOT BE EXPOSED TO RAIN OR

AND OBJECTS FILLED WITH LIQUIDS, SUCH AS VASES,

APPARATUS.

D INCENDIE OU

APPREIL NE DOIT PAS ETRE

A LA PLUIE OU A L HUMIDITE ET AUCUN OBJET REMPLI

L QU UN VASE

, NE DOIT ETRE POSE SUR CELUI-CI.

Input

Input

Input

Outputs
Class 2 Wiring

+

Ch 1

+

Ch 2

+

Ch 3

+

Ch 4

Connect only to “+” terminals

Speaker

A pair of amplifier channels may be bridged together to make a single
output with a power rating equal to the sum of both channel power ratings
at twice the load rating of a single channel. In other words‚ bridging two
amplifiers rated for 160 Watts into 4 Ohms will produce 320 Watts into 8
Ohms.

In Bridged Mode‚ the channels operate at opposite polarity from each other
so that one channel pushes and the other pulls equally. This mode sends the
input signal to one channel and the same signal with its polarity reversed to
the other channel for any two channels (1/2, 3/4 on the CM 2204-AB/DV or
1/3, 2/5, 4/6, 7/8 on the CM 2208-AB/DV). For example, to bridge channels
1 and 2, connect the input signal to the channel 1 input connector using
the standard connections (see # 9, Channel Inputs in Back Panel section).
On channel 2 however, reverse the positive and negative input connections
so that the positive (+) connector is connected channel 2’s negative (-)
receptacle and the negative input connector (-) is connected to channel 2’s
positive (+) receptacle.

Both channel level controls (in this example‚ 1 & 2) MUST be used to
control the signal level and both MUST be set at the same position.

15

Outputs in Bridged Mode

The loudspeaker load is connected only to the designated positive (+)
output terminals of the bridged channels. NEVER ground either side of
the loudspeaker load cable when the amplifier is in Bridged Mode as both
sides are “hot.” If an output patch panel is used‚ all connections must be
isolated from each other and from the panel. When using the low-Z output‚
the minimum nominal load impedance in Bridged Mode is 8 Ohms; this is
equivalent to driving both bridged channels at 4 Ohms. When using the 70
Volt output‚ the bridged output is 140 Volts and the minimum load imped
ance in Bridged Mode is 50 Ohms. Driving loads of lesser impedance may
activate the protection circuits. See Output Modes section for more infor
mation.

Regardless of operating mode‚ NEVER connect the amplifier outputs

Note:

together.

-

-

Output Modes

Caution:

Warning:

Output voltages greater than 120 V RMS are available between the bridged
terminals. CLASS 3 wiring must be used in accordance with national and
local codes to connect the loudspeaker system.

The loudspeaker output connections of this amplifier are hazardous when
live and present a shock hazard when they are energized. Take the following
precautions:

1. Do not touch any bare wires that are connected to the loudspeaker
output connectors.

2. Use insulated loudspeaker cables and touch-proof connectors on the
loudspeakers.

3. Do not attempt to make connections to the output connectors or the
loudspeaker connectors when the amplifier is turned ON.

4. Double-check all connections and make sure there are no exposed wires
or connectors before turning the on amplifier.

5. Make sure there are no frayed cables or wires and that all connections
are tight and secure every time before turning the amplifier on.

6. External wiring connected to these terminals requires installation by a
trained person or the use of ready-made leads or cords.

Each channel of the CM™ 2204-AB/DV or CM 2208-AB/DV can be used in
Direct Drive (Low-Z, 70V or 140V) or Isolated Drive (100V of 50V) appli

-

cations.

Low-Z

70V

100V/50V

This mode allows each output of the channel pair to drive a 4 or 8 Ohm
loudspeaker load. Use Bridged Mode (See Bridged Mode section) to deliver
the power of both channels to a single 8 Ohm load such as a subwoofer.

This mode allows each output of the channel pair to directly drive a 70
Volt constant-voltage audio distribution system. Use the Bridged Mode (See
Bridged Mode section) to deliver the power of both channels to a 140 Volt
constant-voltage audio distribution system.

The output of the CM 2204-AB/DV and CM 2208-AB/DV can be converted
to 100V or 50V with the optional CMX4-50/CMX4-100/CMX8-50/CMX8­100 accessories, respectively.

16

20 speakers @ 10 Watts each = 200 Watts

+

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

8 speakers @ 25 Watts each = 200 Watts

+

Low Z or

70 V Line

Low Z or

70 V Line

+

-

-

+

+

-

-

70 V Line

70 V Line

Outputs
Class 2 Wirin

g

+

Ch1

+

Ch2

+

Ch3

+

Ch4

+

-

-

-

+

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

+

-

-

Example of a 70 Volt constant-voltage distribution system

17

SPECIFICATIONS

Specification CM™ 2208 CM 2204

Non-Bridged Mode

Rated Power (one channel driven)

4 Ohms 160 Watts 160 Watts
8 Ohms 240 Watts 245 Watts
70 Volts (24 Ohms) 230 Watts 220 Watts

Rated Power (all channels driven)

4 Ohms 150 Watts 155 Watts
8 Ohms 210 Watts 240 Watts
70 Volts (24 Ohms) 170 Watts 180 Watts

Minimum Load Impedance 4 Ohms 4 Ohms

Bridged Mode

Rated Power (one channel driven)

8 Ohms 320 Watts 320 Watts
140 Volts 460 Watts 440 Watts

Rated Power (all channels driven)

8 Ohms 300 Watts 310 Watts
140 Volts 340 Watts 360 Watts

Minimum Load Impedance 8 Ohms 8 Ohms

Frequency Response (HPF off)

-1 dB @ 1 Watt (8 Ohm Load) 5 Hz–20 kHz 5 Hz–20 kHz

THD @ rated power‚ 1 kHz (70 V) <0.02% <0.02%

Damping Factor (8 Ohms) >200 >200

Input CMRR <-60 dB <-60 dB

Voltage Gain x40 or 0 dBu (x90) x40 or 0 dBu (x90)

Input Sensitivity (0 dBu setting) 0.775 V 0.775 V

Input Impedance 20 K Ohms balanced 20 K Ohms balanced

10 K Ohms unbalanced 10 K Ohms unbalanced

Noise and Hum

Below rated output‚ 22 Hz–22 kHz -97 dB -97 dB

18

SPECIFICATIONS

Specification CM™ 2208 CM 2204

Current Consumption (Multiply current by 0.5 for 230 V units)

1/3 power, 70 V output 8.0 A 4.4 A
1/8 power, 70 V output 4.0 A 2.3 A
Idle <2 A <1 A

Thermal Emission

1/8 power, 70 V output 724 BTU/hr 473 BTU/hr
1/3 power, 70 V output 947 BTU/hr 621 BTU/hr

Controls

Front: AC switch
CM 2204, Rear: 4 channel input signal attenuators‚ 4 channel HPF select switches, 4 channel gain select switches
CM 2208, Rear: 8 channel input signal attenuators‚ 8 channel HPF select switches, 8 channel gain select switches

Indicator LEDs (front panel)

CM 2204: 4 clip‚ 4 signal‚ 4 protect, 1 power
CM 2208: 8 clip‚ 8 signal‚ 8 protect, 1 power

Protection

Over-temperature‚ DC‚ turn on/off transients‚ subsonic‚ short-circuit, over-current

Connectors

CM 2204, Input: Four 3-position Euro-style detachable terminal blocks
CM 2208, Input: Eight 3-position Euro-style detachable terminal blocks
CM 2204, Output: Four 2-position Euro-style detachable terminal blocks
CM 2208, Output: Eight 2-position Euro-style detachable terminal blocks

Construction

16-gauge steel-reinforced with 12-gauge rack ears

Dimensions

Height: 3.50" (8.84 cm); 2 EIA rack spaces
Width‚ front: 19.00" (48.26 cm)
Width‚ rear: 17.00" (43.18 cm)
Overall depth: 17.05" (43.31 cm)
Mounting depth: 16.63" (42.24 cm) behind front rack ears

Weight

CM 2204-AB: 34 lbs. (15.4 kg) CM2204-DV: 35.5 lbs. (16.1 kg)
CM 2208-AB: 36.5 lbs. (16.5 kg) CM2208-DV: 38 lbs. (17.2 kg)

Power Requirements

120 VAC 60 Hz (-AB versions)
230 VAC 50 Hz (-DV versions)

Test Conditions

120 VAC 60 Hz Line Input voltage maintained (-AB versions)
230 VAC 50 Hz Line Input voltage maintained (-DV versions)

19

SERVICE AND SUPPORT

Support

Contact Us

Customer Service

Technical Support

Web Site

In the unlikely event that your amplifier develops a problem, it must be
returned to an authorized distributor or service center or shipped directly
to our factory.

To obtain service, contact your nearest Crest Audio Service Center,
Distributor, Dealer or any of the worldwide Crest Audio offices (available

online at www.crestaudio.com).

phone [phone] USA
email [e-mail]

phone [phone] USA
email [e-mail]

www.crestaudio.com

Mail

Crest Audio Inc.
16-00 Pollitt Drive
Fair Lawn, NJ 07410 USA

20