Alesis RA100 manuel d'utilisation

A L ES I S RA-100 Reference M a nu a l[...]

CHAPTER 1 – GETTING TO KNOW THE RA-100 1.1 INTRODUCTION.....................................................................................1 Principal Features................................................................................1 Unpacking and Inspection.................................................................3 About This Manu[...]

4.3 KEYBOARD AMPLIFICATION SYSTEM............................................19 4.4 GUITAR AMPLIFICATION SYSTEM..................................................20 4.5 BIAMP SOUND REINFORCEMENT...................................................21 CHAPTER 5 – MAINTAINANCE/SERVICE 5.1 GENERAL INFORMATION.............................................[...]

CHAPTER 1: MEET THE RA-100 1.1 INTRODUCTION Principal Features Congratulations on your purchase of the Alesis RA-100 Reference Amplifier. With all the wondrous advances in both analog and digital electronics in the past few years, it’s easy to forget that an audio chain is only as good as its weakest link. With low-cost digital devices now offeri[...]

power-down. Nonetheless, there’s a 2-second mute on power-up to compensate for any pieces of equipment plugged into the RA-100 that produce transients upon power-up, and receive power at the same time as the RA-100. Also, because the amp doesn’t produce power on/off thumps itself, the mute circuit can be pre-power amp. This allows simpler circu[...]

• No “speaker stress” during shutdown. With traditional protection circuitry, the act of clamping the output devices to a safe value can make the amp unstable with particular notes that interact with the speaker resonance, thus producing oscillation or “motorboating.” This could damage your speakers. The RA-100 uses an elegant clamping de[...]

• Alesis RA-100 power amp with the same serial number as shown on the shipping carton • Power cord. • Four stick-on rubber feet (for shelf mounting, to prevent the RA-100’s bottom surface from scratching the shelf) • Alesis warranty card. It is important to register your purchase; if you have not already filled out your warranty card, ple[...]

CHAPTER 2: INSTALLATION 2.1 REAR PANEL CONNECTIONS The following diagram shows the various rear-panel components. Please refer to this diagram during the procedures described in this chapter. Fuse: 5 Amps (A spare fuse in included in the fuse holder) Right Input Left Input Right Phone Plug Output Left Phone Plug Output Left Push Clip Outputs Right [...]

A THREE-TO-TWO WIRE ADAPTER, CREATES A HAZARDOUS CONDITION. ALESIS CANNOT BE RESPONSIBLE FOR PROBLEMS CAUSED BY USING THE RA-100 OR ANY ASSOCIATED EQUIPMENT WITH IMPROPER AC WIRING. Electrical Service to the RA-100 Although the RA-100 has a maximum audio output rating of 200 watts total into 4 Ω , this does not represent the total current consump[...]

cramped control rooms typically found in smaller studios; any fan noise would interfere with the mixing or monitoring process. The RA-100 should be installed so that its heat sinking is allowed to do its job. Please observe the following: • The RA-100 is designed to perform properly over a range of ambient temperatures from 0° C to +50° C (32°[...]

amp is mounted. Avoiding Electromagnetic Interference Because the RA-100 contains a large power transformer, we recommend that you do not: • Place the RA-100 next to an unshielded video monitor, as the magnetic fields may distort the image. • Place tapes, disks, or other magnetic media close to the RA-100. • Play guitar, bass, or any other in[...]

• 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 [...]

With long cable runs (e.g., over 6 meters/20 feet) in noisy electrical environments, the cable itself can act as an “antenna” and pick up RF fields, AC hum, or other types of interference. To avoid these problems, many professional studios and live sound companies use balanced line connections. The average application will probably not require [...]

along with ground, into the RA-100. The following diagram shows an adapter that assumes pin 2 of the XLR connector is “hot.” 1 2 3 (no connection) Female XLR Connector 1/4 inch phone jack shield If pin 3 is hot, then do not connect pin 2 to anything, and connect the wire from the 1/4” phone jack tip to pin 3 of the XLR female connector. If yo[...]

important. Alesis recommends stranded, rather than solid, cables for flexibility and ease of installation. However, solid cables are equally usable. Never use guitar cords as speaker cables. Because they lack sufficient current- carrying capacity, the amp and speakers will not perform properly and the sound may be degraded. If you make your own cab[...]

required that still maintains the great cost/performance ratio of the RA-100's design. In addition, push connectors are very easy to set up. To connect cable to the push connectors, remove approximately 1/4" of insulation from the end of the wire, being careful not to nick any of the strands. Twist the strands together, press the push ter[...]

CHAPTER 3: USING THE RA-100 3.1 FRONT PANEL CONTROLS The following diagram shows the various front panel controls, as described next. Volume Controls These regulate the input signal going into the RA-100. Always turn the volume controls all the way down (counterclockwise) when making input or output connections to the RA-100. Power should be off as[...]

Mute Switch Because turning the RA-100 on and off generates no spikes within the amplifier, the power switch doubles as a mute switch or “panic button.” For example, if there is a serious feedback problem, you can simply turn off the RA-100, then chase down the source of the problem. Clip Indicators These improve on conventional clipping indica[...]

Near-field monitoring through “reference” speakers has become the preferred way to monitor and mix music. With near-field monitoring, small speakers are placed so that they are a few feet from the engineer’s ears. As a result, room acoustics become less important since the primary acoustic interaction involves direct sound from the speakers r[...]

One path goes from device A to ground via the ground terminal of the three- conductor AC power cord, but A also sees a path to ground through the shielded cable and AC ground of device B. Because ground wires have a small amount of resistance, small amounts of current can flow through ground and generate a voltage along the cable shield. This signa[...]

CHAPTER 4: TYPICAL APPLICATIONS 4.1 STUDIO MONITOR AMP 1622 Mixer RA-100 Near-Field monitors Monitor Outputs in out out in In the studio, the RA-100 is ideal for driving near-field or other reference speakers. In this example, an Alesis 1622 mixer feeds the RA-100, which provides power amplification. The RA-100 outputs feed a set of near-field moni[...]

4.3 KEYBOARD AMPLIFICATION SYSTEM in out out in Inputs Outputs Quadraverb RA-100 A stereo keyboard feeds the Alesis QuadraVerb, which provides reverberation and other signal processing effects. The QuadraVerb outputs feed the RA-100, which then drives a set of small-to-medium size club speakers. With multiple keyboard setups, you may need a mixer t[...]

4.4 GUITAR AMPLIFICATION SYSTEM Speakers in out out in Inputs Outputs Quadraverb GT RA-100 MIDI In MIDI Foot Pedal Many guitarists now use rack mount, component systems for greater flexibility compared to “all-in-one” amps. In this system, a guitar goes through a QuadraVerb GT to provide distortion, chorusing, reverb, and other effects. Its out[...]

4.5 BIAMP SOUND REINFORCEMENT High Frequency Drivers in out out in Ins Crossover High Frequency RA-100 High Frequency Outputs Low Frequency Outputs Ins Outs Low Frequency Speakers Low Frequency RA-100 1622 Mixer Biamplification splits a signal into two separate lines. One carries low frequency signals and the other carries high frequency signals. E[...]

CHAPTER 5: MAINTENANCE/SERVICE 5.1 GENERAL INFORMATION Cleaning Disconnect the AC cord, then use a damp cloth to clean the amplifier’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[...]

CHAPTER 6: TROUBLESHOOTING Begin the troubleshooting process by re-reading the manual to make sure you didn’t miss some important point regarding the unit’s operation. After that, try the following techniques for specific problems. Hum Turn down the volume controls. If the hum goes away, then the source of the hum is either in a unit feeding th[...]

CHAPTER 7: SPECIFICATIONS 24[...]