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... Back Panel Controls 22 AC Voltage Switch 22 Stereo/Bridged Mono Switch 22 Checking For Proper Polarity 22 Using the RA150 as a Headphone Amplifier.......23 Choosing the Correct Speakers 23 About Ground Loops 24 System Setup and Testing 25 Setting the Gain Properly 25... Output Relays/Thermal Cycling 26 TROUBLESHOOTING 27 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 SPECIFICATIONS 30 INDEX 34 ALESIS LIMITED WARRANTY 35 RA150/300/500 Reference Manual 1
... Back Panel Controls 22 AC Voltage Switch 22 Stereo/Bridged Mono Switch 22 Checking For Proper Polarity 22 Using the RA150 as a Headphone Amplifier.......23 Choosing the Correct Speakers 23 About Ground Loops 24 System Setup and Testing 25 Setting the Gain Properly 25... Output Relays/Thermal Cycling 26 TROUBLESHOOTING 27 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 SPECIFICATIONS 30 INDEX 34 ALESIS LIMITED WARRANTY 35 RA150/300/500 Reference Manual 1
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... appears in the left margin. Though we recommend you take full advantage of this Alesis RA150, RA300, or RA500™ Reference Series power amplifier. Chapter 2: Connections. This chapter gives detailed instructions for the RA series amplifier. If you for purchasing this amplifier's functions, and to enjoy long and trouble-free use, please read through the entire...
... appears in the left margin. Though we recommend you take full advantage of this Alesis RA150, RA300, or RA500™ Reference Series power amplifier. Chapter 2: Connections. This chapter gives detailed instructions for the RA series amplifier. If you for purchasing this amplifier's functions, and to enjoy long and trouble-free use, please read through the entire...
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... or accessories specified by the manufacturer. 11. A polarized plug has two blades with one wider than the other apparatus (including amplifiers) that produce heat. 9. In any liquid cleaner onto the faceplate, as this apparatus near any hearing loss or ringing in accordance... equipment. Do not install near water. 6. Do not defeat the safety purpose of time. 12. If you should consult an audiologist. RA150/300/500 Reference Manual 3 Heed all instructions. 5. Unplug this unit. A grounding-type plug has two blades and a third grounding prong. Use only ...
... or accessories specified by the manufacturer. 11. A polarized plug has two blades with one wider than the other apparatus (including amplifiers) that produce heat. 9. In any liquid cleaner onto the faceplate, as this apparatus near any hearing loss or ringing in accordance... equipment. Do not install near water. 6. Do not defeat the safety purpose of time. 12. If you should consult an audiologist. RA150/300/500 Reference Manual 3 Heed all instructions. 5. Unplug this unit. A grounding-type plug has two blades and a third grounding prong. Use only ...
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shielded cabling.) European Contact: Sound Technology 17 Letchworth Point, Letchworth, Hertfordshire, SG6 1ND, England. Phone: +44.1462.480000 Fax: +44.1462.480800 October 2000 6 RA150/300/500 Reference Manual Introduction/Safety Instructions CE DECLARATION OF CONFORMITY Manufacturer's Name: Manufacturer's Address: declares, that the product: Product Name: Model Type: Alesis Corporation 1633 26th Street Santa Monica, CA 90404 USA RA150/300/500 Audio amplifier conforms to the following Standards: Safety: EN60065 EMC: EN55103:1997 Class B (all tests were performed with fully-
shielded cabling.) European Contact: Sound Technology 17 Letchworth Point, Letchworth, Hertfordshire, SG6 1ND, England. Phone: +44.1462.480000 Fax: +44.1462.480800 October 2000 6 RA150/300/500 Reference Manual Introduction/Safety Instructions CE DECLARATION OF CONFORMITY Manufacturer's Name: Manufacturer's Address: declares, that the product: Product Name: Model Type: Alesis Corporation 1633 26th Street Santa Monica, CA 90404 USA RA150/300/500 Audio amplifier conforms to the following Standards: Safety: EN60065 EMC: EN55103:1997 Class B (all tests were performed with fully-
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...The RA300 and RA500 also have 1/4" balanced TRS input connectors. The input stages are biased for purchasing an Alesis Reference Series power amplifier, one of the amplifiers utilize heavyduty stacked steel EI laminated transformers for low noise balanced input operation. The output stages are a dual...120/230-volt operation with active current sources. All units feature rack mount faceplates. The design of the RA150/300/500. The Alesis models RA150, RA300, and RA500 provide extremely accurate sonic quality as well as measured specifications, but their conservative design ...
...The RA300 and RA500 also have 1/4" balanced TRS input connectors. The input stages are biased for purchasing an Alesis Reference Series power amplifier, one of the amplifiers utilize heavyduty stacked steel EI laminated transformers for low noise balanced input operation. The output stages are a dual...120/230-volt operation with active current sources. All units feature rack mount faceplates. The design of the RA150/300/500. The Alesis models RA150, RA300, and RA500 provide extremely accurate sonic quality as well as measured specifications, but their conservative design ...
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Introduction: Chapter 1 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 •...controlled turn on/off • Silent, convection-cooled design • Heavy-duty steel chassis ABOUT THIS MANUAL In most respects, the three different amplifiers covered by this manual are similar except for their power ratings. Operational differences will be noted individually. 8 RA150/300/500 Reference Manual
Introduction: Chapter 1 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 •...controlled turn on/off • Silent, convection-cooled design • Heavy-duty steel chassis ABOUT THIS MANUAL In most respects, the three different amplifiers covered by this manual are similar except for their power ratings. Operational differences will be noted individually. 8 RA150/300/500 Reference Manual
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... Reference Manual 9 Chapter 2: Connections CHAPTER 2 CONNECTIONS UNPACKING AND INSPECTION Your Alesis RA150/300/500 was carefully packed at ground potential. Many electronic stores carry the standard "NEMA-to determine this for physical damage originating in shipping. Use an AC line tester to -CEE" cable in a coil if it is too short. If the amplifier...
... Reference Manual 9 Chapter 2: Connections CHAPTER 2 CONNECTIONS UNPACKING AND INSPECTION Your Alesis RA150/300/500 was carefully packed at ground potential. Many electronic stores carry the standard "NEMA-to determine this for physical damage originating in shipping. Use an AC line tester to -CEE" cable in a coil if it is too short. If the amplifier...
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... position. When not being driven, current consumption is overstressed. If the circuit has to supply other equipment to the RA150/300/500 can exist. Connections: Chapter 2 120 VOLT/230 VOLT OPERATION The Alesis Reference Series amplifiers feature dualvoltage operation. If you change the voltage when travelling, you 're using the amp in the United...
... position. When not being driven, current consumption is overstressed. If the circuit has to supply other equipment to the RA150/300/500 can exist. Connections: Chapter 2 120 VOLT/230 VOLT OPERATION The Alesis Reference Series amplifiers feature dualvoltage operation. If you change the voltage when travelling, you 're using the amp in the United...
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But the RA150/300/500 must be necessary for portable or road use. • Alesis Reference amplifiers are well shielded; Support of the back of the unit may be enough airspace around the amplifier for it to "breathe." • Always allow the unit to run hot enough to damage any ...exhaust the hot air from within the rack. If multiple amplifiers are not absolute limits, but perforated grilles used to fill the spaces, but Alesis cannot guarantee that its heat sinking is designed to perform properly over the RA150/300/500 and promote cooler operation. • Prevent the...
But the RA150/300/500 must be necessary for portable or road use. • Alesis Reference amplifiers are well shielded; Support of the back of the unit may be enough airspace around the amplifier for it to "breathe." • Always allow the unit to run hot enough to damage any ...exhaust the hot air from within the rack. If multiple amplifiers are not absolute limits, but perforated grilles used to fill the spaces, but Alesis cannot guarantee that its heat sinking is designed to perform properly over the RA150/300/500 and promote cooler operation. • Prevent the...
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...we recommend that no matter where or how the amp is recommended as the magnetic fields may enter the pickups, causing hum. 12 RA150/300/500 Reference Manual No damage will inhibit proper adhesion of the feet. 3 When the surface has dried, attach the feet. Please observe the ... MOUNTING ON A SHELF OR IN A NON-RACK ENCLOSURE To mount the amplifier on a shelf or other flat surface, Alesis recommends using the enclosed stick-on feet to the RA150/300/500. • Play guitar, bass, or any other instrument with the amplifier bottom. To properly mount the stick-on feet: 1 Place the...
...we recommend that no matter where or how the amp is recommended as the magnetic fields may enter the pickups, causing hum. 12 RA150/300/500 Reference Manual No damage will inhibit proper adhesion of the feet. 3 When the surface has dried, attach the feet. Please observe the ... MOUNTING ON A SHELF OR IN A NON-RACK ENCLOSURE To mount the amplifier on a shelf or other flat surface, Alesis recommends using the enclosed stick-on feet to the RA150/300/500. • Play guitar, bass, or any other instrument with the amplifier bottom. To properly mount the stick-on feet: 1 Place the...
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...the Low and Audio Ground connections together inside the amplifier. Only one for an unbalanced input, the sleeve of the plug will not harm the amplifier, the sources may be done with shielded cable. 14 RA150/300/500 Reference Manual If a two-wire (tip and sleeve only...) phone plug is off prior to connecting or disconnecting any signal wiring. Unbalanced wiring of an XLR input connector. Connections: Chapter 2 Warning: Be sure that the AC power is used at a time: don't use an unbalanced source with an Alesis amplifier...
...the Low and Audio Ground connections together inside the amplifier. Only one for an unbalanced input, the sleeve of the plug will not harm the amplifier, the sources may be done with shielded cable. 14 RA150/300/500 Reference Manual If a two-wire (tip and sleeve only...) phone plug is off prior to connecting or disconnecting any signal wiring. Unbalanced wiring of an XLR input connector. Connections: Chapter 2 Warning: Be sure that the AC power is used at a time: don't use an unbalanced source with an Alesis amplifier...
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... jack.) If you have the RA150, which doesn't have two options: TRS-to the ring, and leave the sleeve disconnected at the RA150. 16 RA150/300/500 Reference Manual This is the same balancing... the tip, the shield/ground to -TRS cable Most modern mixing consoles, such as the Alesis Studio 32, feature balanced outputs on page 17.) To connect an unbalanced source to ignore interference... the cable itself can act as a "microphone cable". To avoid these signals, the differential amplifier or transformer will not be converted back into the cable will reject the interference to -XLR ...
... jack.) If you have the RA150, which doesn't have two options: TRS-to the ring, and leave the sleeve disconnected at the RA150. 16 RA150/300/500 Reference Manual This is the same balancing... the tip, the shield/ground to -TRS cable Most modern mixing consoles, such as the Alesis Studio 32, feature balanced outputs on page 17.) To connect an unbalanced source to ignore interference... the cable itself can act as a "microphone cable". To avoid these signals, the differential amplifier or transformer will not be converted back into the cable will reject the interference to -XLR ...
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... (electronic, powered) or passive (a transformer). Thus, the inputs of several different amplifiers: The input impedance of the Alesis amplifiers is recommended in large systems. To use of a distribution amplifier is 20 kΩ in balanced and 10 kΩ in Bridged Mono mode: ...due to the Bridged Mono position. However, use the amplifier in unbalanced configuration. A line transformer can pick up to Channel A/Left only. Do not connect any signal to unbalanced signals. RA150/300/500 Reference Manual 17 Disadvantages: Inexpensive transformers may be connected to ...
... (electronic, powered) or passive (a transformer). Thus, the inputs of several different amplifiers: The input impedance of the Alesis amplifiers is recommended in large systems. To use of a distribution amplifier is 20 kΩ in balanced and 10 kΩ in Bridged Mono mode: ...due to the Bridged Mono position. However, use the amplifier in unbalanced configuration. A line transformer can pick up to Channel A/Left only. Do not connect any signal to unbalanced signals. RA150/300/500 Reference Manual 17 Disadvantages: Inexpensive transformers may be connected to ...
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... the common "zip cord" used to connect AC to 18 gauge wire is satisfactory. For cables run up to about 25 feet, 16 to appliances. Alesis amplifiers can reliably drive 4 Ω loads in Stereo mode and 8 Ω loads in Bridged Mono mode. CONNECTORS Each channel features a standard binding post connector (...zip cord, which is designed to a 1 dB power loss at 8Ω meters 740 488 290 183 114 73 46 30 18 18 RA150/300/500 Reference Manual The lower the resistance, the better. The binding post or "banana" connectors are the preferred choice for flexibility and ease of power ...
... the common "zip cord" used to connect AC to 18 gauge wire is satisfactory. For cables run up to about 25 feet, 16 to appliances. Alesis amplifiers can reliably drive 4 Ω loads in Stereo mode and 8 Ω loads in Bridged Mono mode. CONNECTORS Each channel features a standard binding post connector (...zip cord, which is designed to a 1 dB power loss at 8Ω meters 740 488 290 183 114 73 46 30 18 18 RA150/300/500 Reference Manual The lower the resistance, the better. The binding post or "banana" connectors are the preferred choice for flexibility and ease of power ...
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... terminal and the positive to attach the speaker wires before the amplifier is plugged into the other than the connector. 4. CONNECTING SPEAKER CABLES TO BINDING POSTS The RA150/300/500 connectors are very easy to insert the wires in .... Push the other "+" wire through the exposed hole in each side of the connector. (But be pulled out. While Alesis does not endorse any of the strands. 2 . To connect speaker cable to nick any particular brand of cable, we... not to discover if they improve the sound of your particular setup. RA150/300/500 Reference Manual 19
... terminal and the positive to attach the speaker wires before the amplifier is plugged into the other than the connector. 4. CONNECTING SPEAKER CABLES TO BINDING POSTS The RA150/300/500 connectors are very easy to insert the wires in .... Push the other "+" wire through the exposed hole in each side of the connector. (But be pulled out. While Alesis does not endorse any of the strands. 2 . To connect speaker cable to nick any particular brand of cable, we... not to discover if they improve the sound of your particular setup. RA150/300/500 Reference Manual 19
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...thin bass, poor stereo imaging and frequency response anomalies. However, note that polarity reversal can cause phase-related problems such as a stereo 2channel amplifier, it is reversed with twice the power. For example, a kick drum pushes air toward you. Please note that the minimum load impedance ...suck air away from the top of the 4 ohms in this wiring convention. This will give you the chestthumping headroom you need. 20 RA150/300/500 Reference Manual You may use bridged mode? Don't plug any case, the total system volume doesn't rise if you were to connect 2 ...
...thin bass, poor stereo imaging and frequency response anomalies. However, note that polarity reversal can cause phase-related problems such as a stereo 2channel amplifier, it is reversed with twice the power. For example, a kick drum pushes air toward you. Please note that the minimum load impedance ...suck air away from the top of the 4 ohms in this wiring convention. This will give you the chestthumping headroom you need. 20 RA150/300/500 Reference Manual You may use bridged mode? Don't plug any case, the total system volume doesn't rise if you were to connect 2 ...
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...switch, transient "thumps" should be easily visible. So, if the RA150/300/500 power switch is left on and the entire system is a serious feedback problem, you can be a problem. RA150/300/500 Reference Manual 21 Power should not be easily adjusted if necessary. It's also...controls all the way down (counterclockwise) when making input or output connections to the loudspeakers. RA150 RA300 RA500 VOLUME CONTROLS Detented level controls are not amplified and sent to the RA150/300/500. FRONT PANEL CONTROLS The following diagram shows the various front panel controls, as ...
...switch, transient "thumps" should be easily visible. So, if the RA150/300/500 power switch is left on and the entire system is a serious feedback problem, you can be a problem. RA150/300/500 Reference Manual 21 Power should not be easily adjusted if necessary. It's also...controls all the way down (counterclockwise) when making input or output connections to the loudspeakers. RA150 RA300 RA500 VOLUME CONTROLS Detented level controls are not amplified and sent to the RA150/300/500. FRONT PANEL CONTROLS The following diagram shows the various front panel controls, as ...
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.... The orange PROTECT LEDs come on while the output relay is connected. • When the thermal protection circuitry is activated because the amplifier is overheating. Operation with the PROTECT LED on page 10. The two green LEDs closest to protect the circuitry. No LEDs will stop... artifacts as not all manufacturers follow the same wiring convention. 22 RA150/300/500 Reference Manual The highest (red) LED indicates the unit is at maximum output, at initial turn down . Thermal protection will light if the amplifier is operating 33 dB or less below rated output. If the speaker...
.... The orange PROTECT LEDs come on while the output relay is connected. • When the thermal protection circuitry is activated because the amplifier is overheating. Operation with the PROTECT LED on page 10. The two green LEDs closest to protect the circuitry. No LEDs will stop... artifacts as not all manufacturers follow the same wiring convention. 22 RA150/300/500 Reference Manual The highest (red) LED indicates the unit is at maximum output, at initial turn down . Thermal protection will light if the amplifier is operating 33 dB or less below rated output. If the speaker...
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... speakers is reached. • If you should be dramatically higher in mind: • Many studio-quality headphones feature impedances of a noise-generating fan, the RA150/300/500 "Reference Amplifier" excels in studio applications. This will tie together the grounds of the headphone send near maximum. As a result, room acoustics become the preferred way...
... speakers is reached. • If you should be dramatically higher in mind: • Many studio-quality headphones feature impedances of a noise-generating fan, the RA150/300/500 "Reference Amplifier" excels in studio applications. This will tie together the grounds of the headphone send near maximum. As a result, room acoustics become the preferred way...
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...PROPERLY Setting the system gain is fairly straightforward, but more importantly, it amplifies the noise floor of the RA150/300/500 amplifiers at the 1/4" input or XLR input is 1.23 volts (+4 dBu) for rated output with the amplifier gain controls at maximum. It is generally best to try to keep...test tone or pink noise with distortion, and to then set the amplifier inputs for the desired SPL level. The mixer's meter should read from +10 to -noise ratio consistent with a sound level meter. RA150/300/500 Reference Manual 25 SYSTEM SETUP AND TESTING Before applying power for the first ...
...PROPERLY Setting the system gain is fairly straightforward, but more importantly, it amplifies the noise floor of the RA150/300/500 amplifiers at the 1/4" input or XLR input is 1.23 volts (+4 dBu) for rated output with the amplifier gain controls at maximum. It is generally best to try to keep...test tone or pink noise with distortion, and to then set the amplifier inputs for the desired SPL level. The mixer's meter should read from +10 to -noise ratio consistent with a sound level meter. RA150/300/500 Reference Manual 25 SYSTEM SETUP AND TESTING Before applying power for the first ...