Alesis RA150 - Manual

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 StreetSanta Monica, CA 90404USA declares, that the product: Product Name: RA150/300/500 Model Type: Audio amplifier conforms to t...

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 amplifieris a high-current, high-power device andshould be treated with respect and care.Even if you are an audio veteran, weurge you to read the entire manu...

Introduction: Chapter 1 8 RA150/300/500 Reference Manual Reference Series Features- • DC coupled, fully complementary discreteamplifier topology • Actively biased, dual differential inputstages • Wide bandwidth, low distortion design • Fully protected from all fault conditions • LED output level met...

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 packedat the factory, and the shipping carton was designedto protect the unit during shipping. Do not discardthe packing materials; they may be helpful i...

Chapter 2: Connections RA150/300/500 Reference Manual 11 refrigerators, coffee pots, toasters, air conditioning,or stage lighting, plug the RA150/300/500 into adifferent circuit with a lesser load. O PERATING E NVIRONMENT T EMPERATURE C ONSIDERATIONS IN R ACK M OUNTING The RA150/300/500 can be mount...

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 jackinputs, and unbalanced RCA/phono inputs . TheRA300 and RA500 feature combination XLR inputjacks as well. The inp...

Chapter 2: Connections RA150/300/500 Reference Manual 15 C ABLES Use only high quality cables when interfacingequipment with the RA150/300/500. These shouldbe good quality shielded cables with a stranded (notsolid) internal conductor. Although quality cablescost more, they do make a difference. Rout...

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) innoisy electrical environments, the cable itself can actas an “antenna” and pick up RF fields, AC hum, orother types of interference. To avoid theseproblems, many p...

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

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 signalwiring. 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. Howeve...

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 theinstrument it’s reproducing. For example, a kickdrum pushes air toward you on the initial transient,so a speaker reproducing a kick drum should haveits cone push ...

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 frontpanel 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...

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 canoccur if a piece of equipment “sees” two or more different paths to ground, as shown below. Device A Devi ce B shielded...

Chapter 3: Operation RA150/300/500 Reference Manual 25 S YSTEM S ETUP AND T ESTING Before applying power for the first time, doublecheck the wiring to insure that everything is firmlyconnected and that the proper signals are being fedto the proper places. If a low frequency signal in amulti-amplifie...

Operation: Chapter 3 26 RA150/300/500 Reference Manual Amplifier input clipping On the other hand, the maximum level at theamplifier’s input terminals is +26 dBu, regardlessof the setting of the channel input level controls. Itis possible that the output signal from the sourcemay be too high and, th...

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 forAlesis Reference Series amplifiers. Aside from the front panel gain control...

Troubleshooting: Chapter 4 28 RA150/300/500 Reference Manual Symptom Cause Solution Intermittent amplifierinput signal Clean input connectors,check wiring If the sound cuts out fora minute or two and thenreturns, the amplifiermay be overheating andcycling through thermalprotect mode Check for short ...

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 wa...

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 ...

Specifications RA150/300/500 Reference Manual 33 Architect's and Engineer's Specifications The power amplifier shall be a two-channel unitcapable of being switched to single-channelbridged mode operation. All components shall beof high quality and mechanical construction andoptimized for high reliab...

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

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...