Alesis POWER AMPLIFIER RA150 manuale d’uso

REFERENCE SERIES POWER AMPLIFIERS R EFERENCE M ANUAL ©2000 Alesis Corporation ™ ™ ™[...]

Alesis RA150-500 Reference Manual © Copyright 2000, Alesis Studio Electronics, Inc. All rights reserved. Reproduction in whole or in part is prohibited. “RA150/300/500” and “Reference Series” are trademarks of Alesis Studio Electronics, Inc. ALESIS CONTACT INFORMATION Alesis Studio Electronics, Inc. 1633 26th Street Santa Monica, CA 90404 [...]

RA150/300/500 Reference Manual 1 C ONTENTS Introduction ...................................................... 2 How to Use This Manual ........................... 2 I MPORTANT S AFETY I NSTRUCTIONS .... 3 Instructions de Sécurité Importantes (French) ...... 4 Beim Benutzen dieses Produktes beachten Sie bitte die folgenden Sicherheitshinweise: (G[...]

Introduction/Safety Instructions 2 RA150/300/500 Reference Manual I 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. H OW TO U SE T HIS M ANUAL This m[...]

Introduction/Safety Instructions RA150/300/500 Reference Manual 3 I MPORTANT S AFETY I NSTRUCTIONS S 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[...]

Introduction/Safety Instructions 4 RA150/300/500 Reference Manual I NSTRUCTIONS DE S ÉCURITÉ I MPORTANTES (F RENCH ) S 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 prés[...]

Introduction/Safety Instructions RA150/300/500 Reference Manual 5 B EIM B ENUTZEN DIESES P RODUKTES BEACHTEN S IE BITTE DIE FOLGENDEN S ICHERHEITSHINWEISE : (G ERMAN ) 1. 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.[...]

Introduction/Safety Instructions 6 RA150/300/500 Reference Manual CE D ECLARATION OF C ONFORMITY Manufacturer’s Name: Alesis Corporation Manufacturer’s Address: 1633 26th Street Santa Monica, CA 90404 USA declares, that the product: Product Name: RA150/300/500 Model Type: Audio amplifier conforms to the following Standards: Safety: EN60065 EMC:[...]

Chapter 1: Introduction RA150/300/500 Reference Manual 7 C HAPTER 1 A BOUT THE RA150/300/500 P RINCIPAL F EATURES Please remember that a power amplifier is a high-current, high-power device and should be treated with respect and care. 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. [...]

Introduction: Chapter 1 8 RA150/300/500 Reference Manual Reference Series Features- • DC coupled, fully complementary discrete amplifier topology • Actively biased, dual differential input stages • Wide bandwidth, low distortion design • Fully protected from all fault conditions • LED output level metering (RA 300, RA 500) • Front panel[...]

Chapter 2: Connections RA150/300/500 Reference Manual 9 C HAPTER 2 C ONNECTIONS U NPACKING AND I NSPECTION Your Alesis RA150/300/500 was carefully packed at the factory, and the shipping carton was designed to protect the unit during shipping. Do not discard the packing materials; they may be helpful in the unlikely event that you need to return yo[...]

Connections: Chapter 2 10 RA150/300/500 Reference Manual 120 V OLT /230 V OLT O PERATION 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-vol[...]

Chapter 2: Connections RA150/300/500 Reference Manual 11 refrigerators, coffee pots, toasters, air conditioning, or stage lighting, plug the RA150/300/500 into a different circuit with a lesser load. O PERATING E NVIRONMENT T EMPERATURE C ONSIDERATIONS IN R ACK M OUNTING The RA150/300/500 can be mounted in an equipment rack (taking up 2 rack spaces[...]

Connections: Chapter 2 12 RA150/300/500 Reference Manual M OUNTING ON A S HELF OR IN A N ON -R ACK E 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: 1 Place the amplifier upsi[...]

Chapter 2: Connections RA150/300/500 Reference Manual 13 I NPUTS I NPUT J ACK C 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 [...]

Connections: Chapter 2 14 RA150/300/500 Reference Manual 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 com[...]

Chapter 2: Connections RA150/300/500 Reference Manual 15 C ABLES 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 obs[...]

Connections: Chapter 2 16 RA150/300/500 Reference Manual B ALANCED OR U NBALANCED ? 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 compani[...]

Chapter 2: Connections RA150/300/500 Reference Manual 17 Isolation transformer or direct box If your mixer or other sound source doesn't have a balanced output, you may turn it into a balanced signal with an external device, either active (electronic, powered) or passive (a transformer). These commonly available audio accessories have a balanc[...]

Connections: Chapter 2 18 RA150/300/500 Reference Manual O UTPUTS Warning: Be sure that the AC power is off prior to connecting or disconnecting any signal wiring. W HAT ' S THE L OAD I MPEDANCE ? Alesis amplifiers can reliably drive 4 Ω loads in Stereo mode and 8 Ω loads in Bridged Mono mode. However, the impedance of a loudspeaker varies[...]

Chapter 2: Connections RA150/300/500 Reference Manual 19 In recent years, expensive audiophile cables of high current capacity have appeared. These have been somewhat controversial; some feel the extra expense produces an audible improvement in sound quality, while others find no sonic difference between audiophile cables and other heavy-duty wirin[...]

Connections: Chapter 2 20 RA150/300/500 Reference Manual T HE I MPORTANCE OF S PEAKER P 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 reverse[...]

Chapter 3: Operation RA150/300/500 Reference Manual 21 C HAPTER 3 O PERATION F RONT P ANEL C ONTROLS The following diagram shows the various front panel controls, as described next. RA150 RA300 RA500 V OLUME C ONTROLS Detented level controls are on the front panel, where they can be easily adjusted if necessary. These regulate the input signal goin[...]

Operation: Chapter 3 22 RA150/300/500 Reference Manual P ROTECT /C LIP I 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. Because of the RA150/300/500’s[...]

Chapter 3: Operation RA150/300/500 Reference Manual 23 U SING THE RA150 AS A H EADPHONE A 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. Due[...]

Operation: Chapter 3 24 RA150/300/500 Reference Manual A BOUT G ROUND L OOPS 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. Devic e A D evi c e B s hie l d ed c ab le p at h 2 p at h 1 To AC p owe[...]

Chapter 3: Operation RA150/300/500 Reference Manual 25 S YSTEM S ETUP AND T ESTING 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 transd[...]

Operation: Chapter 3 26 RA150/300/500 Reference Manual 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 amplifie[...]

Chapter 4: Troubleshooting RA150/300/500 Reference Manual 27 C HAPTER 4 T ROUBLESHOOTING T ROUBLESHOOTING I NDEX 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 maint[...]

Troubleshooting: Chapter 4 28 RA150/300/500 Reference Manual Symptom Cause Solution Intermittent amplifier input signal Clean input connectors, check wiring If the sound cuts out for a minute or two and then returns, the amplifier may be overheating and cycling through thermal protect mode Check for short circuits in the output wiring or excessive [...]

Chapter 4: Troubleshooting RA150/300/500 Reference Manual 29 O BTAINING R EPAIR S ERVICE Before contacting Alesis, check over all your connections, and make sure you’ve read the manual. Customers in the USA and Canada: If the problem persists, contact Alesis USA at www.alesis.com & find the Product Support web page. Make sure you have the uni[...]

Specifications 30 RA150/300/500 Reference Manual S PECIFICATIONS Reference 150 Size 18.9" W x 3.9" H x 10.25" D (480mm x 99 mm x 260 mm) Rack units 2RU height Weight 15lbs = 6.8Kg Rated output, per channel 4 ohms @ 1kHz, .02% THD+N 75 watts RMS per channel 8 ohms @ 1kHz, .05% THD+N 45 watts RMS per channel 8 ohms, bridged mono mode 1[...]

Specifications RA150/300/500 Reference Manual 31 Reference 500 Size 18.9" W x 5.63" H x 10.71" D (480mm x 143 mm x 272 mm) Rack units 3 RU height Weight 28.5lbs = 13.0Kg Rated output, per channel 4 ohms @ 1kHz, .02% THD+N 250 watts RMS per channel 8 ohms @ 1kHz, .05% THD+N 150 watts RMS per channel 8 ohms, bridged mono mode 500 watts[...]

Specifications 32 RA150/300/500 Reference Manual RA500 RA300[...]

Specifications RA150/300/500 Reference Manual 33 Architect's and Engineer's Specifications The power amplifier shall be a two-channel unit capable of being switched to single-channel bridged mode operation. All components shall be of high quality and mechanical construction and optimized for high reliability under adverse physical and ele[...]

Index 34 RA150/300/500 Reference Manual I NDEX 120-volt to 230-volt conversion, 10, 22 AC cord, 9 AC power, 10 balanced inputs, 14 balanced lines, 16 banana plugs, 19 Bridged Mono mode, 17, 20 cables shielded input, 15 speaker, 18 class AB, 7, 33 cooling, 7, 11 direct box, 17 Fuse, 10 gain setting, 25 ground audio, 9, 14 ground lifter, 24 ground lo[...]

RA150/300/500 Reference Manual 35 A LESIS L IMITED W ARRANTY ALESIS ("ALESIS") warrants this product to be free of defects in material and workmanship for a period of one (1) year for parts and for a period of one (1) year for labor from the date of original retail purchase. This warranty is enforceable only by the original retail purchas[...]

Warranty 36 RA150/300/500 Reference Manual[...]