System Setup and Testing ...25 Setting the Gain Properly...25 Output Relays/Thermal Cycling ...26 ROUBLESHOOTING Troubleshooting Index...27 Care and Maintenance ...28 Cleaning ...28 Refer All Servicing to Alesis ...28 Obtaining Repair Service ...29 Customers outside the USA and Canada: ...29 PECIFICATIONS ...34 NDEX...
Introduction/Safety Instructions NTRODUCTION Thank you for purchasing this Alesis RA150, RA300, or RA500™ Reference Series power amplifier. To take full advantage of this amplifier’s functions, and to enjoy long and trouble-free use, please read this user’s manual carefully. OW TO...
MPORTANT AFETY SYMBOLS USED IN THIS PRODUCT This symbol alerts the user that there are important operating and maintenance instructions in the literature accompanying this unit. This symbol warns the user of uninsulated voltage within the unit that can cause dangerous electric shocks.
Introduction/Safety Instructions NSTRUCTIONS DE YMBOLES UTILISÉS DANS CE PRODUIT Ce symbole alèrte l’utilisateur qu’il existe des instructions de fonctionnement et de maintenance dans la documentation jointe avec ce produit. Ce symbole avertit l’utilisateur de la présence d’une tension non isolée à l’intérieur de l’appareil pouvant engendrer des chocs électriques.
ENUTZEN DIESES FOLGENDEN ICHERHEITSHINWEISE Lesen Sie die Hinweise. 2. Halten Sie sich an die Anleitung. 3. Beachten Sie alle Warnungen. 4. Beachten Sie alle Hinweise. 5. Bringen Sie das Gerät nie mit Wasser in Berührung. 6. Verwenden Sie zur Reinigung nur ein weiches Tuch.
Product Name: Model Type: conforms to the following Standards: Safety: EMC: European Contact: October 2000 ONFORMITY Alesis Corporation 1633 26th Street Santa Monica, CA 90404 RA150/300/500 Audio amplifier EN60065 EN55103:1997 Class B (all tests were performed with fully- shielded cabling.)
Even if you are an audio veteran, we urge you to read the entire manual to make the best use of the RA150/300/500. Thank you for purchasing an Alesis Reference Series power amplifier, one of the most advanced and highest value amplifiers available.
You as the consignee must make any shipping claims; neither your dealer nor Alesis can do this for you. If the amplifier was not shipped to you, i.e. you picked it up from your dealer, contact the dealer as soon as possible for assistance.
Connections: Chapter 2 120 V /230 V The Alesis Reference Series amplifiers feature dual- voltage operation. The AC input voltage is selected by a recessed switch on the back panel. The tab is recessed and a tool (small screw driver, pencil, pen, etc.) is required to shift from 120-volt to 230-volt...
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.
Connections: Chapter 2 OUNTING ON A NCLOSURE To mount the amplifier on a shelf or other flat surface, Alesis recommends using the enclosed stick-on feet to avoid scratching the shelf’s surface with the amplifier bottom. To properly mount the stick-on feet:...
NPUTS NPUT HARACTERISTICS The RA150/300/500 include two balanced, 1/4" TRS (tip-ring-sleeve, 3-conductor) phone jack inputs, and unbalanced RCA/phono inputs. The RA300 and RA500 feature combination XLR input jacks as well. The inputs are wired according to IEC standards, as shown in the table below. Connection Audio Ground High (+)
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Warning: Be sure that the AC power is off prior to connecting or disconnecting any signal wiring. The input circuits of the Alesis amplifiers are electronically balanced. They may be fed from either symmetrical (“balanced”) or unbalanced sources. On the RA300 and RA 500, there are two combination XLR/1/4”...
RA150/300/500 Reference Manual ABLE 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.
RA150/300/500: You have two options: TRS-to-TRS cable Most modern mixing consoles, such as the Alesis Studio 32, feature balanced outputs on 1/4" TRS jacks. This is the same balancing connector used by the RA150/300/500. Get a 3-conductor cable with a 1/4"...
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RA150/300/500 Reference Manual To feed the same source to several different amplifiers: The input impedance of the Alesis amplifiers is 20 configuration. Thus, the inputs of several amplifiers may be connected in parallel if desired. The maximum number of amplifier channels will depend on the minimum output load impedance of the device feeding the amplifiers.
Warning: Be sure that the AC power is off prior to connecting or disconnecting any signal wiring. S THE Alesis amplifiers can reliably drive 4 Stereo mode and 8 loads in Bridged Mono mode. However, the impedance of a loudspeaker varies with frequency, and its nominal rated impedance is not necessarily its minimum impedance.
While Alesis does not endorse any particular brand of cable, we suggest that you investigate different cable types for yourself to discover if they improve the sound of your particular setup.
Connections: Chapter 2 MPORTANCE OF OLARITY The speaker cone’s motion should mimic the instrument it’s reproducing. For example, a kick drum pushes air toward you on the initial transient, so a speaker reproducing a kick drum should have its cone push air toward you. If the polarity is reversed, the cone will suck air away from you.
RONT ANEL ONTROLS The following diagram shows the various front panel controls, as described next. RA150 RA300 RA500 OLUME ONTROLS Detented level controls are on the front panel, where they can be easily adjusted if necessary. These regulate the input signal going into the RA150/300/500.
Operation: Chapter 3 ROTECT NDICATORS Clip lights for each channel indicate the onset of actual clipping. Even if the problem occurs for only a few microseconds, a pulse-stretching circuit will allow the LED to light long enough for you to see that a problem is occurring.
RA150 SING THE EADPHONE MPLIFIER The RA150 is particularly suited for use driving high-impedance headphones in studio applica- tions. However, the power is considerably greater than that provided by most "headphone amplifiers", which are often rated at 1 watt or below.
Operation: Chapter 3 BOUT ROUND A hum or buzz may be introduced into some audio systems by a phenomenon known as a ground loop. This can occur if a piece of equipment “sees” two or more different paths to ground, as shown below. shielded cable Device A...
YSTEM ETUP AND Before applying power for the first time, double check the wiring to insure that everything is firmly connected and that the proper signals are being fed to the proper places. If a low frequency signal in a multi-amplified system is applied to a high frequency transducer, the transducer can be damaged, and a loose connection can cause noise...
Operation: Chapter 3 Amplifier input clipping On the other hand, the maximum level at the amplifier’s input terminals is +26 dBu, regardless of the setting of the channel input level controls. It is possible that the output signal from the source may be too high and, thus, distorted before it reaches the amplifier gain control, either because the source device is clipping or the amplifier input...
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.
Troubleshooting: Chapter 4 Symptom Audio cuts in and out Unit shuts down, all lamps are off Thin or Muffled Sound ARE AND AINTENANCE LEANING Disconnect the AC cord, then use a damp cloth to clean the RA150/300/500’s metal and plastic surfaces.
Tape a note to the top of the unit describing the problem, include your name and a phone number where Alesis can contact you if necessary, as well as instructions on where you want the product returned. Alesis will pay for standard one-way shipping back to you on any repair covered under the terms of this warranty.
Specifications Reference 150 Size Rack units Weight Rated output, per channel 4 ohms @ 1kHz, .02% THD+N 8 ohms @ 1kHz, .05% THD+N 8 ohms, bridged mono mode Signal to Noise Ratio Frequency Response Damping Factor Slew Rate Input Sensitivity Maximum input level Input impedance Crosstalk...
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Reference 500 Size Rack units Weight Rated output, per channel 4 ohms @ 1kHz, .02% THD+N 8 ohms @ 1kHz, .05% THD+N 8 ohms, bridged mono mode Signal to Noise Ratio Frequency Response Damping Factor Slew Rate Input Sensitivity Maximum input level Input impedance Crosstalk All measurements done over a 20Hz-22,000Hz range with 1KHz sine wave at Full Scale, except for the dynamic...
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150 watts (RA150), 300 watts (RA300), or 500 watts (RA500) into an 8-ohm load when operated in bridged mono mode with no more than .05% total harmonic distortion. The amplifier shall be an Alesis RA150/300/500 Reference Series power amplifier. at least Specifications...
ALESIS reserves the right to update any unit returned for repair. ALESIS reserves the right to change or improve design of the product at any time without prior notice.
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