RB-981
STEREO POWER AMPLIFIER
AMPLIFICATEUR DE PUISSANCE STÉRÉO
STEREO-ENDSTUFE
ETAPA DE POTENCIA ESTEREOFONICA
POWER AMPLIFIER RB-981
POWER
PROTECTION
BRIDGED MONO
Owner’s Manual
Guide d’utilisation
Bedienungsanleitung
Manual de Instrucciones
Figure 1: Controls and Connections / Commandes et branchments
Bedienelemente und Anschüsse / Controles y Conexiones
POWER AMPLIFIER RB-981
POWER
PROTECTION
BRIDGED MONO
1
2
3
4
SPEAKER IMPEDANCE
STEREO 4 OHMS MINIMUM
BRIDGED 8 OHMS MINIMUM
WARNING:TO REDUCE THE RISK OF FIRE
OR ELECTRICAL SHOCK, DO NOT EXPOSE
THIS EQUIPMENT TO RAIN OR MOISTURE.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
POWER AMPLIFIER
MODEL NO. RB-981
POWER CONSUMPTION: 400W
AVIS: RISQUE DE CHOC ELECTRIQUE–NE PAS OUVRIR
SPEAKERS
RIGHT
LEFT
RIGHT INPUT
LEFT INPUT
SERIAL NO.
5
6
5
7
STEREO POWER AMPLIFIER RB-981
Figure 2: Stereo Connections – Inputs and Speakers / [French Translation]
[German Translation] / [Spanish Translation]
PREAMPLIFIER / PRÉAMPLIFICATEUR / VORVERSTÄRKER / PREAMPLIFICADOR
PREAMP OUTPUTS
L
R
ROTEL RB-981
WARNING:TO REDUCE THE RISK OF FIRE
OR ELECTRICAL SHOCK, DO NOT EXPOSE
THIS EQUIPMENT TO RAIN OR MOISTURE.
SPEAKER IMPEDANCE
STEREO
CAUTION
4
OHMS MINIMUM
RISK OF ELECTRIC SHOCK
DO NOT OPEN
POWER AMPLIFIER
MODEL NO. RB-981
BRIDGED
8 OHMS MINIMUM
AVIS: RISQUE DE CHOC ELECTRIQUE–NE PAS OUVRIR
POWER CONSUMPTION: 400W
SPEAKERS
RIGHT
LEFT
RIGHT INPUT
LEFT INPUT
SERIAL NO.
Figure 3: Bridged Mono Connections – Inputs and Speakers / [French Translation]
[German Translation] / [Spanish Translation]
PREAMPLIFIER / PRÉAMPLIFICATEUR / VORVERSTÄRKER / PREAMPLIFICADOR
PREAMP OUTPUTS
L
R
ROTEL RB-981
WARNING:TO REDUCE THE RISK OF FIRE
OR ELECTRICAL SHOCK, DO NOT EXPOSE
THIS EQUIPMENT TO RAIN OR MOISTURE.
SPEAKER IMPEDANCE
STEREO
CAUTION
4
OHMS MINIMUM
RISK OF ELECTRIC SHOCK
DO NOT OPEN
POWER AMPLIFIER
MODEL NO. RB-981
BRIDGED
8 OHMS MINIMUM
AVIS: RISQUE DE CHOC ELECTRIQUE–NE PAS OUVRIR
POWER CONSUMPTION: 400W
SPEAKERS
RIGHT
LEFT
RIGHT INPUT
LEFT INPUT
SERIAL NO.
JUMPER LOCATIONS / FRENCH TRANSLATION /
GERMAN TRANSLATION / SPANISH TRANSLATION
ENGLISH
Contents (circled numbers refer to illustration)
About Rotel
A family whose passionate interest in music led them to manufac-
ture high fidelity components of uncompromising quality founded
Rotel over 30 years ago. Through the years that passion has re-
mained undiminished and the family goal of providing exceptional
value for audiophiles and music lovers, regardless of their budget,
is shared by all Rotel employees.
About Rotel __________________________________________ 1
Getting Started ______________________________________ 2
A Few Precautions
Placement
2
2
AC Power and Control ________________________________ 2
The engineers work as a close team, listening to, and fine tuning
each new product until it reaches their exacting musical stan-
dards. They are free to choose components from around the
world in order to make that product the best they can. You are
likely to find capacitors from the United Kingdom and Germany,
semi conductors from Japan or the United States, while toroidal
power transformers are manufactured in Rotel’s own factory.
AC Power Input
Power Switch
Protection Circuitry
7
2
2
2
1
and Power Indicator
2
3
Input Signal Connection ______________________________ 3
Input Signal Connection
5
3
Speaker Connection __________________________________ 3
Rotel’s reputation for excellence has been earned through hun-
dreds of good reviews and awards from the most respected re-
viewers in the industry, who listen to music every day. Their
comments keep the company true to its goal – the pursuit of
equipment that is musical, reliable and affordable.
Speaker Selection
3
3
3
3
Speaker Wire Selection
Polarity and Phasing
Stereo Speaker Connection
6
Bridged Mode Operation ______________________________ 4
All of us at Rotel thank you for buying this product and hope it will
bring you many hours of enjoyment.
Resetting Jumpers
4
4
Input Connection
Bridged Speaker Connection
4
Troubleshooting ______________________________________ 4
Front Panel Power Indicator Is Not Lit
Fuse Replacement
No Sound
4
4
4
4
Protection Indicator Is Lit
Specifications ________________________________________ ?
1
STEREO POWER AMPLIFIER RB-981
Getting Started
AC Power and Control
Thank you for purchasing the Rotel RB-981 Stereo Power Ampli-
fier. When used in a high-quality music or home theater system,
your Rotel amplifier will provide years of musical enjoyment.
AC Power Input 7
Because of its high power rating, the RB-981 can draw consider-
able current. Therefore, it should be plugged directly into a 2-pin
polarized wall outlet. Do not use an extension cord. A heavy duty
multi-tap power outlet strip may be used if it (and the wall outlet)
is rated to handle the current demanded by the RB-981 and all the
other components connected to it.
The RB-981 is a high-power, two-channel power amplifier, provid-
ing the highest level of audio performance. Discrete output de-
vices, a massive power supply, premium components, and Rotel’s
Balanced Design ensure superb sound quality. High current capa-
bility allows the RB-981 to drive the most demanding loudspeakers.
Be sure the power switch on the front panel of the RB-981 is
turned off (in the out position). Then, connect the supplied power
cord to the AC power outlet.
Be aware that the RB-981 is capable of high power levels, in ex-
cess of 130 watts per channel. Make sure that your speakers can
handle the power of the RB-981. If in doubt about your speakers,
ask your local Rotel audio retailer for advice.
Your RB-981 is configured at the factory for the proper AC line
voltage in the country where you purchased it (either 115 volts AC
or 230 volts AC with a line frequency of either 50 Hz or 60 Hz). The
AC line configuration is noted on a decal on the back panel.
The RB-981 is straightforward in its installation and operation. If
you have experience with other stereo power amplifiers, you
shouldn’t find anything perplexing. Plug in a pair of high-quality
RCA cables from your preamp into the amplifier inputs, wire up
your speakers, and enjoy.
Note: Should you move your RB-981 amplifier to another country,
it is possible to reconfigure your amplifier for use on a different
line voltage. Do not attempt to perform this conversion yourself.
Opening the enclosure of the RB-981 exposes you to dangerous
voltages. Consult a qualified service person or the Rotel factory
service department for information.
A Few Precautions
Please read this manual carefully. In addition to basic installation
and operating instructions, it provides valuable information on
various RB-981 system configurations as well as general informa-
tion that will help you get optimum performance from your system.
Please contact your authorized Rotel audio retailer for answers to
any questions you might have. In addition, all of us at Rotel wel-
come your questions and comments.
If you are going to be away from home for an extended period of
time such as a month-long vacation, it is a sensible precaution to
unplug your amplifier (as well as other audio and video compo-
nents) while you are away.
Save the RB-981 shipping carton and all enclosed packing mate-
rial for future use. Shipping or moving the RB-981 in anything
other than the original packing material may result in severe dam-
age to your amplifier.
Power Switch 1 and Power Indicator 2
The power switch is located on the front panel of your amplifier.
To turn the amplifier on, push the switch in. The LED indicator
above the switch will light, indicating that the amplifier is turned
on. To turn the amplifier off, push the button again and return it to
the out position.
Fill out and send in the owner’s registration card packed with the
RB-981. Also be sure to keep the original sales receipt. It is your
best record of the date of purchase, which you will need in the
event warranty service is ever required.
Protection Circuitry
3
The RB-981 features a thermal protection circuit that protects the
amplifier against potential damage in the event of extreme or
faulty operating conditions. Unlike many designs, the RB-981’s
protection circuit is independent of the audio signal and has no
impact on sonic performance. Instead, the protection circuit
monitors the temperature of the output devices and shuts down
the amplifier if temperatures exceed safe limits.
Placement
Because of its high power output, the RB-981 may generate con-
siderable heat. The heat sinks and ventilation openings in the am-
plifier are more than capable of dissipating this heat under normal
conditions, but don’t smother your amplifier. There must be ad-
equate clearance around the chassis. The ventilation slots in the
top cover must be unblocked, and there must be reasonable air-
flow around the amplifier. Use common sense when placing the
amplifier in a cabinet or when stacking other equipment.
Likewise, remember the weight of the amplifier when you select
an installation location. Make sure that the shelf or cabinet can
support its considerable bulk. Again, use common sense.
2
ENGLISH
Speaker Wire Selection
Most likely, you will never see this protection circuitry in action.
However, should a faulty condition arise, the amplifier will stop
playing and the LED indicator on the front panel will light up.
Use insulated two-conductor stranded wire to connect the RB-981
to the speakers. The size and quality of the wire can have an au-
dible effect on the performance of the system. Standard speaker
wire will work, but can result in lower output or diminished bass
response, particularly over longer distances. In general, heavier
wire will improve the sound. For best performance, you may want
to consider special high-quality speaker cables. Your Rotel audio
retailer can help in the selection of appropriate cables for your
system.
If this happens, turn the amplifier off, let it cool down for several
minutes, and attempt to identify and correct the problem that
caused the protection circuitry to engage. When you turn the am-
plifier back on, the protection circuit will automatically reset and
the indicator LED should go out.
In most cases, the protection circuitry activates because of a fault
condition such as shorted speaker wires, or inadequate ventila-
tion leading to an overheating condition. In very rare cases, highly
reactive or extremely low impedance speaker loads could cause
the protection circuit to engage.
Polarity and Phasing
The polarity — the positive/negative orientation of the connec-
tions — for every speaker and amplifier connection must be con-
sistent so all the speakers will be in phase. If the polarity of one
connection is mistakenly reversed, bass output will be very weak
and stereo imaging degraded. All wire is marked so you can iden-
tify the two conductors. There may be ribs or a stripe on the insu-
lation of one conductor. The wire may have clear insulation with
different color conductors (copper and silver). There may be po-
larity indications printed on the insulation. Identify the positive
and negative conductors and be consistent with every speaker
and amplifier connection.
If the protection circuitry triggers repeatedly and you are unable
to isolate and correct the faulty condition, contact your Rotel au-
dio retailer for assistance in troubleshooting.
Input Signal Connection
5
[See Figure 2 for normal stereo wiring illustration.]
The RB-981 has conventional RCA type input connectors, the type
found on nearly all audio equipment.
Stereo Speaker Connection 6
The RB-981 has two pairs of color coded binding posts on the
back panel. These connectors accept bare wire, connector lugs,
or dual banana type connectors (except in the European Commu-
nity countries where their use is not permitted).
Note: To prevent loud noises that neither you nor your speakers
will appreciate, make sure the amplifier is turned off when you
make any signal connections.
Route the wire from the RB-981 to the speakers. Give yourself
enough slack so you can move the components enough to allow
access to the speaker connectors.
Select a high quality pair of audio interconnect cables. Connect
the left channel output of your preamp to the left channel input on
the RB-981. Connect the right channel output of your preamp to
the right channel input.
If you are using dual banana plugs, connect them to the wires and
then plug into the backs of the binding posts. The hexagonal
thumbscrews of the binding posts should be screwed in all the
way (clockwise).
If you are using terminal lugs, connect them to the wires. If you
are attaching bare wires directly to the binding posts, separate
the wire conductors and strip back the insulation from the end of
each conductor. Be careful not to cut into the wire strands. Un-
screw (turn counterclockwise) the binding post hexagonal thumb-
screws. Place the connector lug around the binding post shaft, or
insert the bundled wire into the hole in the shaft. Turn the hexago-
nal thumbscrews clockwise to clamp the connector lug or wire
firmly in place.
Speaker Connection
Speaker Selection
We recommend using loudspeakers with a nominal impedance of
4 ohms or higher with the RB-981. You should exercise some cau-
tion in driving multiple pairs of speakers in parallel configuration,
because the effective impedance the amplifier sees is cut in half.
For example, when driving two pair of 8 ohm speakers, the ampli-
fier sees a 4 ohm load. When driving multiple speakers in parallel,
it is recommended that you select speakers with a nominal imped-
ance of 8 ohms or higher. Speaker impedance ratings are less
than precise. In practice, very few loudspeakers will present any
problems for the RB-981. See your Rotel audio retailer if you have
any questions.
Note: Be sure there are no loose wire strands that could touch
adjacent wires or connectors.
3
STEREO POWER AMPLIFIER RB-981
Bridged Mono Operation
Troubleshooting
[See Figure 3 for bridged operation jumper setting and connec-
tion illustration.]
Most difficulties in audio systems are the result of poor or wrong
connections, or improper control settings. If you encounter prob-
lems, isolate the area of the difficulty, check the control settings,
determine the cause of the fault and make the necessary
changes. If you are unable to get sound from the RB-981, refer to
the suggestions for the following conditions:
The two channels of the RB-981 can be “bridged”. In this configu-
ration the single channel produces a massive 390 watts! This fea-
ture allows you to increase the overall power output of your
system by bridging the RB-981 and adding a second bridged RB-
981. Or the RB-981 is bridged to drive a monophonic subwoofer.
Note however that when the RB-981 is bridged the speaker con-
nected to it must have an impedance of 8 ohms or more.
Front Panel Power Indicator Is Not Lit
No main power to the RB-981. Check the front panel power
switch. Make sure that it is set to the on position. Check AC power
connections at the amplifier and the AC outlet.
In order to use the RB-981 in bridged mode, three “jumper” con-
nectors inside the amplifier must be moved from one set of pins
to another. This task should be done by a qualified technicain. See
your Rotel audio retailer. In addition the RB-981 is connected to
the other components in a different way. When the RB-981 is
setup for bridged operation the Bridged Mono indicator light 4
on the front panel will light.
Fuse Replacement
If everything checks out correctly and you still cannot get the am-
plifier to turn on, the internal power fuse may have blown. If you
believe this has happened, contact your Rotel dealer for informa-
tion on where to take your amplifier to get the fuse replaced.
Resetting Jumpers
No Sound
If the amp is getting AC power, but is producing no sound, check
the Protection indicator on the front panel. If it is lit, see below. If
not, check all of your connections and control settings on associ-
ated components.
Before opening the RB-981 cabinet to reset the jumpers, the
power cord must be unplugged from the wall. DO NOT OPEN THE
CABINET OF THE RB-981 BEFORE THE POWER CORD HAS BEEN
UNPLUGGED FROM THE WALL. FAILURE TO DO SO WILL EXPOSE
YOU TO HAZARDOUS VOLTAGES.
Protection Indicator Is Lit
The front panel indicator lights when the RB-981 protection cir-
cuits have shut off the amplifier. Typically, this occurs only when
the ventilation openings are blocked, when there is faulty speaker
wiring, or after a period of extreme use. Turn off the system and
wait for the amp to cool. Then push the front panel power switch
in and out to reset the protection devices. If the problem is not
corrected or reoccurs, there is a problem with the system or the
amplifier itself.
After the power cord has been unplugged, remove the screws
that hold the cabinet cover in place and slide the cover off the
amplifier. Locate the three jumper pin blocks labeled S 601, S 602
and S 603. The factory standard (stereo) position of the jumpers is
on pins 1 and 2 of each block. There is a * mark on the circuit
board next to this position. To convert the RB-981 to bridged mono
move all three jumpers so they are on pins 2 and 3 of each jumper
pin block. Replace the cover of the cabinet. Do not plug the RB-
981 power cord back into the wall outlet until the cabinet cover
has been replaced.
Input Connection
When using the RB-981 in bridged mono mode, connect the cable
from the preamplifier output to the left input. No connection is
made to the right input.
Bridged Speaker Connection
When using the RB-981 in bridged mono mode, the wire to the
speakers is connected to the positve terminals of the left and right
channels. Connect the wire that goes to the postive terminal of
the speaker to the positve terminal of the left channel of the RB-
981. Connect the wire that goes to the negative terminal of the
speaker to the positve terminal of the right channel of the RB-981.
No connections are made to the negative terminals of the RB-981.
4
5
STEREO POWER AMPLIFIER RB-981
Specifications
Technische Daten
Continuous Power Output
(20-20 kHz, < 0.03%, 8 ohms)
130 watts/ch
Dauerausgangsleistung
(20-20 kHz, < 0,03%, 8 Ohm)
130 Watt pro Kanal
< 0,03 %
Total Harmonic Distortion (20Hz-20kHz, 8 ohms) < 0.03%
Gesamtklirrfaktor (20 - 20.000 Hz, 8 Ohm)
Intermodulation Distortion (60 Hz : 7 kHz, 4:1)
Frequency Response ( +0.5, -3dB dB)
Damping Factor (20-20,000 Hz, 8 ohms)
Speaker Impedance (Normal mode)
Signal to Noise Ratio (IHF A network)
Input Impedance/Sensitivity
< 0.03%
Intermodulationsverzerrung (60 Hz : 7 kHz, 4:1) < 0,03 %
4Hz-100kHz
1000
Frequenzgang ( +0.5, -3dB dB)
Dämpfungfaktor (20-20,000 Hz, 8 Ohm)
Lautsprecherimpedanz (Normalbetrieb)
Geräuschspannungsabstand (IHF A)
Eigangimpedanz/-empfindlichkeit
Spannungsversorgung
4 bis 100.000 Hz
1000
4 ohms nominal
120 dB
Minimum 4 Ohm
120 dB
33 k Ohms/1.0 volt
33 k Ohms/1,0 V
230 Volts, 50 Hz
400 Watt
Power Requirements
115 Volts, 60 Hz or
230 Volts, 50 Hz
Max. Leistungsaufnahme
Power Consumption
400 Watts
Abmessungen (B x H x T)
440 x 121 x 305 mm
10.2 kg
Dimensions (W x H x D)
440 x 121 x 305 mm
173/8 x 43/4 x 12"
Nettogewicht
Weight (net)
10.2 kg, 22.4 lb.
Änderungen, die dem technischen Fortschritt dienen, bleiben vorbehalten.
All specifications are accurate at the time of printing.
Rotel reserves the right to make improvements without notice.
Fiche technique
Características Técnicas
Puissance de sortie continue
(20 Hz à 20 kHz, 0,03 %, 8 ohms)
130 watts par canal
Potencia Continua de Salida
(20-20.000 Hz, THD menor del < 0’03%, 8 ohmios)
130 vatios/canal
Distortion harmonique total (20-20k Hz, 8 ohms) 0.03 %
Distortión Armónica Total (20-20.000 Hz, 8 ohmios) < 0’03%
Distortion d’intermodulation (60 Hz : 7 kHz, 4:1) 0.03 %
Distortión por Intermodulación (60 Hz : 7 kHz, 4:1) < 0’03%
Résponse en fréquence ( +0.5, -3dB dB)
4 Hz à 100 kHz
Respuesta en Frecuencia ( +0’5, -3dB dB)
4Hz-100.000 Hz
Facteur d’amortissement (20-20,000 Hz, 8 ohms) 1000
Factor de Amortiguamiento (20-20.000 Hz, 8 ohmios) 1000
Impedancia de las Caja Acústicas (modo Normal) minima de 4 ohmios
Relación Señal/Ruido (norma IHF/ ponderación A) 120 dB
Impédance (mode normal)
Rapport signal/bruit (IHF A network)
Impédance d’entrée/Sensibilité
Alimentation
4 ohms minimum
120 dB
33 kohms/1.0 volt
Sensibilidad/Impedancia de Entrada
Alimentación
33 kohmios/1’0 V
115 Volts, 60 Hz ou
230 Volts, 50 Hz
115 voltios/60 Hz
230 voltios/50 Hz
Consommation
Dimensions (L x H x P)
Poids (net)
400 Watts
Consumo
400 vatios
440 x 121 x 305 mm
10.2 kg
Dimensiones (An x Al x P)
Peso Neto
440 x 121 x 305 mm
10.2 kg
Toutes les spécifications de cet appareil étaient exactes au moment de
l’impression de ce guide. Rotel se réserve le droit de les modifier sans
préavis.
Todas estas especificaciones son correctas enel momento de la
impresión del presente manual de instrucciones.
Rotel se reserva el deracho a realizar modificaciones en las mismas sin
aviso previo.
?
RB-981
STEREO POWER AMPLIFIER
The Rotel Company, Ltd.
10-10 Shinsen-Cho
Shibuya-Ku
Tokyo 150-0045
Japan
Phone: +81-3-5458-5325
Fax: +81-3-5458-5310
Rotel Deutschland
Kleine Heide 12
D-33790 Halle/Westf.
Germany
Phone: 05201-87170
Fax: 05201-73370
Rotel of America
54 Concord Street
North Reading, MA 01864-2699
USA
Phone: 978-664-3820
Fax: 978-664-4109
082 OMRB-981
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