Chapter 2: Connections

CABLES

Use only high quality cables when interfacing equipment with the RA150/300/500. These should be good quality shielded cables with a stranded (not solid) internal conductor. Although quality cables cost more, they do make a difference. Route cables to the RA150/300/500 correctly by observing the following precautions.

•Do not bundle audio cables with AC power cords.

•Avoid running audio cables near sources of electromagnetic interference such as transformers, monitors, computers, etc.

•Do not place cables where they can be stepped on. Although stepping on a cable may not cause immediate damage, it can compress the insulation between the center conductor and shield (thus degrading performance) or reduce the cable’s reliability.

•Avoid twisting the cable or having it make sharp, right angle turns.

•Never unplug a cable by pulling on the wire itself. Always unplug by firmly grasping the body of the plug and pulling directly outward. If you experience difficulty in removing the plug, sometimes a slight rotating motion while unplugging will solve the problem.

•Keep the cable contacts clean at all time. Oxidation may lead to intermittent contacts, degraded sound quality, or even distortion. DO NOT USE AN ABRASIVE TO CLEAN A DIRTY PLUG. This may remove some of the plug’s conductive plating. Instead, spray contact cleaner on a clean, lint-free cloth and vigorously rub the plug until the oxidation is removed.

•Although Alesis does not endorse any specific product, chemicals such as Tweek and Cramolin, when applied to electrical connectors, are claimed to improve the electrical contact between connectors.

•NEVER PLUG OR UNPLUG INPUT CABLES UNLESS THE RA150/300/500 IS TURNED OFF, UNPLUGGED FROM THE AC LINE, OR HAS THE CHANNEL 1 AND CHANNEL 2 LEVEL CONTROLS TURNED TO MINIMUM LEVEL. Failure to observe these precautions may result in damage to your speakers if the cable being plugged into the RA150/300/500 is carrying a signal, and the level is turned up.

CABLE WIRING TIPS

If you decide to wire your own cables, Alesis recommends that you use three-conductor shielded cable (even in an installation that uses unbalanced wiring) with either a braided or foil-type shield. Connect one conductor to the phone jack tip connection to carry the hot signal, and the shield connection to the sleeve. The other conductor should also connect to the shield since it is not good practice to depend on the shield wire itself to complete the signal connection. This is because the shield wires are more subject to breakage, especially in portable installations, than the more protected internal insulated wires. By using a second “safety” conductor for ground, the worst that could happen with a broken shield would be a rise in noise or hum due to the lack of shielding. If the ground connection were completely lost, there would be either extremely loud hum or major loss of audio.

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Alesis RA500, RA150, RA300 manual Cables, Cable Wiring 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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