Chapter 2: Connections

refrigerators, coffee pots, toasters, air conditioning, or stage lighting, plug the RA150/300/500 into a different circuit with a lesser load.

OPERATING ENVIRONMENT

TEMPERATURE CONSIDERATIONS IN RACK MOUNTING

The RA150/300/500 can be mounted in an equipment rack (taking up 2 rack spaces or 3 spaces for the RA500), placed on a shelf, tucked away in a vocal booth, etc. When you install it, keep in mind that heat is the major enemy of electronic equipment. Fortunately, the RA150/300/500’s protection circuitry will not allow the unit to run hot enough to damage any of the circuitry. However, sustained high-temperature operation sufficient to cause limiting will adversely affect the sound quality, and eventually the amplifier will shut itself off for as long as the excessive temperature conditions exists.

The RA150/300/500 has extensive heat sinking to minimize overheating, as well as eliminate the need for a ventilating fan. The latter feature is crucial for the cramped control rooms typically found in smaller studios; any fan noise would interfere with the mixing or monitoring process.

But the RA150/300/500 must be installed so that its heat sinking is allowed to do its job. Please observe the following:

•The RA150/300/500 is designed to perform properly over a range of ambient temperatures from 0° C to +50° C (32° F to 122° F), in up to 80% non-condensing humidity. These are not absolute limits, but Alesis cannot guarantee that the RA150/300/500 will meet its published specs if operated outside of these ranges. If necessary, use a fan to blow air over the RA150/300/500 and promote cooler operation.

•Prevent the side heat sink fins from becoming obstructed. There should be enough airspace around the amplifier for it to “breathe.”

•Always allow adequate ventilation behind the RA150/300/500. Do not seal any enclosure that holds the RA150/300/500.

•Never throw a coat or other flexible fabric or covering over the top of the amp when it’s in use.

RA150/300/500 Reference Manual

•You may wish to leave an empty rack space above or below the amp to promote good air flow. If multiple amplifiers are mounted in the same rack, there should be at least one rack space left between them; solid blank panels may be used to fill the spaces, but perforated grilles used as fillers will help exhaust the hot air from within the rack.

OTHER RACK MOUNTING TIPS

•Due to the RA150/300/500’s weight (from 15 to 28.5 lbs.), it’s a good idea to mount it in the bottom of the rack frame. Support of the back of the unit may be necessary for portable or road use.

•Alesis Reference amplifiers are well shielded; however, mounting low-level electronics some distance away from power amplifiers is common practice to reduce the possibility of electromagnetic interference into the low level units, which may sometimes be unusually susceptible to picking up such radiation.

When wiring a rack, it is good installation practice to route all AC wiring along one side of the rack and all audio wiring along the other side to avoid coupling AC-borne interference into the audio.

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Alesis RA300, RA150, RA500 Operating Environment, Temperature Considerations in Rack Mounting, Other Rack Mounting Tips
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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.
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