The Rotel RB-990BX is a stereo power amplifier designed to deliver high-quality audio performance. This manual provides essential information for its safe and optimal use, covering setup, operation, and maintenance. Rotel emphasizes its commitment to advanced electronic technology and extensive experience in audio equipment manufacturing, aiming to provide users with satisfaction through superior sound, top performance, and functional beauty achieved through human-engineering concepts.
Function Description
The RB-990BX functions as a stereo power amplifier, meaning it takes a low-level audio signal from a preamplifier and boosts it to a level sufficient to drive loudspeakers. It is designed to work with speaker systems having an impedance range of 4-16 ohms. The amplifier is equipped with a protection circuit to prevent damage from accidents or excessive heat. When activated, this circuit will cut off sound from the speakers, and a protection indicator will light up. This is a crucial safety feature, ensuring the longevity of both the amplifier and connected speakers. The protection circuit also prevents popping noises when the unit is turned on, delaying sound output for a few seconds after power-on.
Usage Features
To ensure maximum safety and optimal performance, several usage features and guidelines are provided:
- Power Supply: The amplifier must be connected to a household wall outlet with a voltage that matches the electrical rating specified on the unit's rear panel nameplate. The AC line cord should only be connected or disconnected after turning off the power switch to prevent potential shock noise or damage to the speakers.
- Ventilation: Proper ventilation is critical for the RB-990BX. Users must never block any ventilation holes located on the top and bottom of the unit. Ample space around the unit should be provided to prevent excessive heat buildup, which could lead to damage. Avoid placing the unit in highly enclosed spaces like near a wall or on a bookshelf, as poor ventilation can negatively affect performance.
- Cabinet Integrity: The cabinet should never be opened to avoid electric shock or damage to internal components. If a foreign object accidentally falls inside, the power should be turned off, the unit unplugged, and a qualified electrician or dealer consulted.
- Placement: The unit should be placed on a level and flat surface, free from humidity, vibration, high temperatures, and direct sunlight.
- Speaker Connection: When connecting speakers, users should ensure the correct polarity (+ to + and - to -) between the amplifier's terminals and the speaker wires. The speaker terminals are screw-type; users should strip the cord ends, twist the leads firmly, insert them, and tighten the screws clockwise to secure the connection and prevent accidental dislodgement.
- Preamplifier Connection: The RB-990BX connects to a preamplifier using RCA pin cables. The OUTPUT L and R jacks of the preamplifier should be connected to the INPUT LEFT and RIGHT jacks of the power amplifier, respectively.
- Power On/Off: The unit features a power button. Pressing it once turns the unit on, and pressing it a second time releases it to cut off power.
- Power Indicator: A power indicator glows when the unit is turned on.
- Protection Indicator: This indicator normally lights for several seconds upon turning on the power and then goes off, signifying normal operating status. If it glows continuously, it indicates abnormally high internal temperature. The indicator will remain on until the temperature drops to a normal level, after which it will go off, signaling the unit's return to normal operation.
- Volume Control: Before operating, all connections should be properly made. Before turning on the power to the unit, the preamplifier volume control should always be set to minimum. After turning on the preamplifier and then the RB-990BX, users can reproduce a desired source and gradually raise the volume level on the preamplifier.
- Cable Recommendations: To achieve the most exceptional sound quality and allow the RB-990BX to operate at its full potential, Rotel strongly recommends using high-quality RCA pin cables for connecting to the control amplifier and low-capacity, low-impedance speaker cables.
- Hum and Noise Reduction: In high-fidelity installations, hum can arise from the interconnection of components like turntables, tuners, and amplifiers, or from speaker placement, wiring, or grounding issues. If hum is experienced, users should disconnect everything but the speakers from the unit. If a turntable is connected and hum or howling occurs, moving the turntable away from the speakers may help. Defective cable connections or running cables too close to strong AC fields can also induce hum. Noise during broadcast reception can be caused by external objects like fluorescent lamps or household appliances with motors or thermostats. Relocating the unit away from noise sources or using an improved outdoor antenna may resolve the issue. If the cause cannot be found, a dealer or qualified electrician should be consulted.
Maintenance Features
Proper maintenance ensures the longevity and optimal performance of the RB-990BX:
- Cleaning: The unit should be cleaned only as recommended by the manufacturer. For the front panel, avoid using chemicals such as benzine or thinners. Instead, use a soft, dry cloth to clean the unit.
- Non-use Periods: If the appliance will be left unused for a long period, the power cord should be unplugged from the outlet.
- Object and Liquid Entry: Care should be taken to prevent objects from falling into and liquids from spilling inside the appliance.
- Moving the Unit: When transporting the unit, remove the AC cord from the wall outlet and all other connected cords from the rear panel to prevent wire breakage and short circuits.
- Water Exposure: If the unit gets wet, immediately disconnect the AC cord and consult a dealer or qualified electrician.
- Owner's Manual: Keep the owner's manual near the unit and record the serial number (found on the rear panel) on the cover for future reference.
- Servicing: The user should not attempt to service the appliance beyond the means described in the operating instructions. All other servicing should be referred to qualified service personnel. This is particularly important if the power-supply cord or plug is damaged, objects have fallen or liquid has spilled into the appliance, the appliance has been exposed to rain, the appliance does not appear to operate normally or exhibits a marked change in performance, or the cabinet is damaged.
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