Alesis RA150, RA300, RA500 manual Care and Maintenance, Cleaning, Refer ALL Servicing to Alesis

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Troubleshooting: Chapter 4

Symptom

Cause

Solution

Audio cuts in and out

Intermittent amplifier

Clean input connectors,

 

input signal

check wiring

 

If the sound cuts out for

Check for short circuits in

 

a minute or two and then

the output wiring or

 

returns, the amplifier

excessive ambient

 

may be overheating and

temperature

 

cycling through thermal

 

 

protect mode

 

 

Dirty volume pot

Move volume pot up and

 

 

down several times

Unit shuts down, all lamps

Blown fuse

Obtain the proper size fuse

are off

 

(see page 10) and replace it

 

Internal thermal fuse

Shut off power and let

 

activated

amplifier cool down

Thin or Muffled Sound

Defective loudspeaker

Replace drivers

 

drivers

 

 

 

 

 

In a multi-amplified

Check crossover and

 

system with a low level

connections. Check

 

crossover network, bad

speaker connections.

 

outputs from the

 

 

network, or improperly

 

 

connected loudspeakers

 

 

Balanced connector with

Make sure input cables are

 

one side disconnected, or

connected to ground as

 

no ground with an

required

 

unbalanced input

 

CARE AND MAINTENANCE

CLEANING

Disconnect the AC cord, then use a damp cloth to clean the RA150/300/500’s metal and plastic surfaces. For heavy dirt, use a non-abrasive household cleaner such as Formula 409™ or Fantastik™. DO NOT SPRAY THE CLEANER DIRECTLY ONTO THE FRONT OF THE UNIT AS IT MAY DESTROY THE LUBRICANTS USED IN THE SWITCHES AND CONTROLS! Spray onto a cloth, then use cloth to clean the unit.

REFER ALL SERVICING TO ALESIS

We believe that the RA150/300/500 is one of the best amplifiers that can be made using current technology, and should provide years of trouble- free use. However, should problems occur, DO NOT attempt to service the unit yourself. Service on this product should be performed only by qualified technicians. NO USER-SERVICEABLE PARTS INSIDE.

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RA150/300/500 Reference Manual

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Contents Power Amplifiers Reference SeriesAlesis Contact Information Contents HOW to USE this Manual IntroductionImportant Safety Instructions Safety Symbols Used in this ProductSymboles Utilisés Dans CE Produit Instructions DE Sécurité Importantes FrenchLesen Sie die Hinweise CE Declaration of Conformity EMCPrincipal Features Reference Series Features About this ManualPower Considerations ConnectionsAC Cord and Grounding Electrical Service to VOLT/230 Volt OperationFuse Temperature Considerations in Rack Mounting Operating EnvironmentOther Rack Mounting Tips Mounting on a Shelf or in a NON-RACK Enclosure Avoiding Electromagnetic InterferenceInput Jack Characteristics InputsBalanced wiring of an XLR input Connector To use an unbalanced source with an Alesis amplifierCable Wiring Tips CablesBalanced or UNBALANCED? To connect a balanced line output to feed the RA150/300/500To connect an unbalanced source to the amplifier input To use the amplifier in Bridged Mono mode To feed the same source to several different amplifiersWhats the Load IMPEDANCE? ConnectorsOutputs Speaker CablesConnecting Speaker Cables to Binding Posts To connect speaker cable to the connectorsOutput Connections for Bridged Operation To connect a speaker in bridged mono modeImportance of Speaker Polarity Should you use bridged mode?Mute Switch ON-OFF SwitchVolume Controls OperationMeters RA300 and RA500 Back Panel ControlsChecking for Proper Polarity Using the RA150 AS a Headphone Amplifier Choosing the Correct SpeakersDevice a Shielded cable Path Device B To AC power service About Ground LoopsSystem Setup and Testing Setting the Gain ProperlyAmplifier input clipping Output RELAYS/THERMAL CyclingTroubleshooting Troubleshooting IndexCare and Maintenance CleaningRefer ALL Servicing to Alesis Obtaining Repair Service Customers Outside the USA and CanadaSpecifications ReferenceDimensioned drawings RA300 RA500 Architects and Engineers Specifications Index Alesis Limited Warranty Please Register Your Product OnlineWarranty

RA150, RA500, RA300 specifications

The Alesis RA series of amplifiers—comprising the RA300, RA500, and RA150—have earned a respected spot in the audio equipment landscape, catering to both musicians and audio professionals. With a blend of innovative technology, robust performance, and user-friendly features, these amplifiers offer solutions for various sound requirements.

Starting with the RA300, this amplifier delivers a solid output of 150 watts per channel at 4 ohms, making it ideal for smaller studio setups or personal listening environments. It is built with a lightweight yet durable design, employing a modern Class AB architecture that ensures low distortion and high audio fidelity. The RA300 features comprehensive input options, including balanced XLR and quarter-inch TRS inputs, allowing seamless integration into diverse setups. Additionally, the built-in protection circuitry prevents overheating and damage during prolonged use, ensuring longevity and reliability.

The RA500 steps up the power and performance, presenting a robust 250 watts per channel at 4 ohms, making it suitable for larger venues and demanding applications. It utilizes advanced thermal management technology, which aids in efficient heat dissipation, ensuring the amplifier operates smoothly even under heavy load. The RA500 also boasts significant dynamic range and headroom, making it a preferred choice for professional environments where audio clarity and volume are paramount. The addition of a frequency response that spans from 20Hz to 20kHz means it can faithfully reproduce a wide range of audio frequencies.

Meanwhile, the RA150 serves as a versatile option for various applications, delivering 75 watts per channel at 4 ohms. Despite its compact size, the RA150 does not compromise on sound quality or functionality. Its Class AB amplifier technology results in enhanced audio accuracy, making it popular among beginner studios and educational settings. The straightforward controls and indicators ensure that users can quickly adjust settings for optimal performance.

All three amplifiers in the Alesis RA series share a common goal: to provide high-quality sound amplification without unnecessary complexity. Their combination of solid construction, advanced technologies, and thoughtful features make them suitable for a multitude of audio environments—from home studios to professional gigs. Whether you opt for the RA300, RA500, or RA150, you are investing in a reliable tool designed to deliver exceptional audio performance, catering to the needs of discerning audiophiles and professionals alike.