Alesis RA500, RA150, RA300 manual Troubleshooting Index

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Chapter 4: Troubleshooting

CHAPTER 4

TROUBLESHOOTING

TROUBLESHOOTING INDEX

Once all gain adjustments are made and proper operation is confirmed, no special considerations are required for Alesis Reference Series amplifiers. Aside from the front panel gain controls, there are no user adjustments or routine maintenance operations necessary (or available). If you experience problems while operating your RA150/300/500, please use the following table to locate possible causes and solutions before contacting Alesis Product Support for assistance.

Symptom

Cause

Solution

No audio from outputs

No input audio

Hook up inputs

 

Bad cables

Replace the cables.

 

Amplifier is turned

Set levels to "12:00" or above

 

down

 

 

Is the amplifier very hot?

Normal operation will resume

 

Is the ambient

when its internal temperature

 

temperature and/or the

has dropped to reliable levels.

 

air flow in the rack high?

 

 

If so, the amplifier may

 

 

be in thermal protect

 

 

mode (PROTECT LEDs

 

 

on)

 

 

Power is not connected

Time for a coffee break.

Low output power

Line voltage set

Set the switch on the back panel

 

improperly

to the "120 V" position

Bass disappears, speakers

Amplifier accidentally

Set the switch on the back panel

sound out of phase

set to "Bridge Mono"

to the "stereo" position

 

mode when wired for

 

 

stereo

 

Buzz from outputs

Input cables are crossing

Make sure that the

 

a power cable or near a

RA150/300/500 and its audio

 

transformer

cables are kept away from

 

 

power cables, other power

 

 

transformers and wall warts.

 

 

Use balanced inputs instead of

 

 

unbalanced

 

Bad cables

Replace the cable with a new,

 

 

high-quality cable.

 

Problem with the source

Try plugging a known line-level

 

 

source to the amplifier inputs to

 

 

see if the problem remains.

 

Noise induced from a

Connect to a different electrical

 

bad AC ground or noisy

circuit; use balanced inputs or

 

AC circuit

plug amp and source into the

 

 

same AC circuit

RA150/300/500 Reference Manual

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Contents Reference Series Power AmplifiersAlesis Contact Information Contents Introduction HOW to USE this ManualSafety Symbols Used in this Product Important Safety InstructionsInstructions DE Sécurité Importantes French Symboles Utilisés Dans CE ProduitLesen Sie die Hinweise EMC CE Declaration of ConformityPrincipal Features About this Manual Reference Series FeaturesAC Cord and Grounding Power ConsiderationsConnections Fuse Electrical Service toVOLT/230 Volt Operation Other Rack Mounting Tips Temperature Considerations in Rack MountingOperating Environment Avoiding Electromagnetic Interference Mounting on a Shelf or in a NON-RACK EnclosureInputs Input Jack CharacteristicsTo use an unbalanced source with an Alesis amplifier Balanced wiring of an XLR input ConnectorCables Cable Wiring TipsTo connect an unbalanced source to the amplifier input Balanced or UNBALANCED?To connect a balanced line output to feed the RA150/300/500 To feed the same source to several different amplifiers To use the amplifier in Bridged Mono modeOutputs ConnectorsWhats the Load IMPEDANCE? Speaker CablesTo connect speaker cable to the connectors Connecting Speaker Cables to Binding PostsImportance of Speaker Polarity To connect a speaker in bridged mono modeOutput Connections for Bridged Operation Should you use bridged mode?Volume Controls ON-OFF SwitchMute Switch OperationChecking for Proper Polarity Meters RA300 and RA500Back Panel Controls Choosing the Correct Speakers Using the RA150 AS a Headphone AmplifierAbout Ground Loops Device a Shielded cable Path Device B To AC power serviceSetting the Gain Properly System Setup and TestingOutput RELAYS/THERMAL Cycling Amplifier input clippingTroubleshooting Index TroubleshootingRefer ALL Servicing to Alesis Care and MaintenanceCleaning Customers Outside the USA and Canada Obtaining Repair ServiceReference SpecificationsDimensioned drawings RA300 RA500 Architects and Engineers Specifications Index Please Register Your Product Online Alesis Limited WarrantyWarranty

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.