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SRA-120
Power Amplifier
Operating Manual
Level (dB) Level (dB) Stereo
-1 0 -1 0 Headphones
-3 -3
- -
SRA-120
-6 -20 -6 -20
Stereo
Channel 2
Power Amplifier Sig. Clip Sig. Clip Protect
Protect
-10 -10 SRA-120
SRA-120
Power
Channel 1 Channel 2
(Mono)
ASHLY AUDIO INC.
847 Holt Road Webster, NY 14580-9103 Phone: (716) 872-0010
Toll-Free: (800) 828-6308 Fax: (716) 872-0739 Internet: http://www.ashly.com/
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Operating Manual - SRA-120 Power Amplifier Table Of Contents 1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 UNPACKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 AC POWER REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1 AC Voltage Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Operating Manual - SRA-120 Power Amplifier 9 DESIGN THEORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 10 TROUBLESHOOTING TIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 10.1 No Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 10.2 Distorted Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Operating Manual - SRA-120 Power Amplifier 1. INTRODUCTION 3. AC POWER REQUIREMENTS Congratulations on your purchase of the Ashly 3.1 Voltage Requirements SRA-120 professional stereo power amplifier. This single Your SRA-120 amplifier is supplied with a three rack-space (1 3/4" height) amplifier delivers a substan- conductor grounded AC power cord, and should be tial amount of power with exceptional audio quality and plugged into a standard 3-wire grounded electrical outlet many features typica
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Operating Manual - SRA-120 Power Amplifier 4.2 Output Cables 5. RACK-MOUNTING REQUIREMENTS The wire gauge used for speaker cables is impor- tant, in that inadequate wire gauge adds significant re- 5.1 Mechanical sistance to the speaker’s own impedance, reducing the All Ashly amps are designed to fit in standard power which is actually delivered to the speaker. It also 19-inch racks. Avoid placing the amp immediately next results in a decrease in the damping factor and possible to devices whic
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Operating Manual - SRA-120 Power Amplifier Stereo Level (dB) Level (dB) 0 0 -1 -1 Headphones -3 -3 - - SRA-120 -6 -6 -20 -20 Stereo Power Amplifier Sig. Clip Sig. Clip Protect -10 -10 Channel 1 Channel 2 (Mono) 6. FRONT PANEL FEATURES 6.5 Protect Indicators Protect mode in the SRA-120 is automatically 6.1 Power Switch activated during extreme fault conditions, as well as dur- When the unit is switched on there is a 2 second ing power-up and power-down. When in protect mode, as delay, during whic
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Operating Manual - SRA-120 Power Amplifier Channel 2 Protect SRA-120 Power 7. REAR PANEL FEATURES Tip (+) Ring (-) Sleeve (Ground) 7.1 Inputs Stereo Phone Plug The input of the SRA-120 amplifier is equipped used for balanced with balanced 1/4" tip-ring-sleeve (TRS) phone jacks and balanced screw-terminal inputs. Each channel's connec- Pins are 2 = (+) numbered tors are internally wired in parallel and may be used with 3 = (-) XLR Male in the 1 = (gnd) connector balanced or unbalanced connection
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Operating Manual - SRA-120 Power Amplifier In situations where the power amp and its signal and the channel 1 red binding post becomes the (-) out-of- source are separated by great distances, a ground voltage phase speaker terminal. To properly operate in bridged difference may exist between the amp’s chassis ground mono mode, the Mono switch must also be selected. and the input cable’s ground. Connection of these two grounds through the jumper strap may cause large ground 7.4 Stereo/Mono Swit
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Operating Manual - SRA-120 Power Amplifier 8.2 Stereo Playback Monitoring System Here the SRA-120 is fed from a low line-level (-10dBu) stereo tape machine or CD player. Only the sensitiv- ity switch should be depressed. 8.3 Mono Operation in High Level Bi-Amped System Here the SRA-120 is fed from the high frequency output of a professional two-way crossover. The stereo/ mono and normal/bridged switches are both depressed to obtain the maximum amount of power when amplifying a mono signal. In
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Operating Manual - SRA-120 Power Amplifier 9. DESIGN THEORY A toroidal power supply transformer is used to minimize induced hum noise and to reduce overall weight. Ashly engineers set out to design a single rack Epoxy sealed output relays are used to protect speakers space stereo power amplifier delivering a minimum of and the amplifier from turn on transients, excessive load 120 watts total with the sonic excellence, mechanical rug- current and overheat conditions. A unique rear-panel sen- ged
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Operating Manual - SRA-120 Power Amplifier • Signal present indicators active but clip LED is not: SRA-120. Isolate which piece of equipment in the audio chain is causing the noise. The audio Applied input signal is distorted before it gets to source medium itself may contain the noise. the amp. Check to see if a piece of equipment in the signal chain before the amp is clipping. 10.4 Excessive Hum Noise Normally the amplifier should be operated with This is usually caused by "ground loops" i
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Operating Manual - SRA-120 Power Amplifier 12. SPECIFICATIONS 12.13 Power Requirements: 110-125VAC, 50-60Hz (240V Available) 12.1 Output Power: 12.14 Shipping Weight: Maximum Average Power, 0.1% THD, 1KHz RMS Watts Per Channel, Both Channels Driven 20 lbs. 8 ohms: 40W Specification conditions are 120VAC 60Hz at 25°C. 4 ohms: 60W 13. WARRANTY POLICY Bridged Mono Mode: We thank you for your expression of confidence 8 ohms: 120W in Ashly products. The unit you have just purchased is protected by a
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Operating Manual - SRA-120 Power Amplifier 14. SCHEMATICS: 13 Figure 15.1: SRA-120 Block Diagram and Wiring Diagram.
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Operating Manual - SRA-120 Power Amplifier 14 Figure 15.2: SRA-120 Channel One Schematic Diagram.
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Operating Manual - SRA-120 Power Amplifier 15 Figure 15.3: SRA-120 Channel Two Schematic Diagram.
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Operating Manual - SRA-120 Power Amplifier ASHLY AUDIO INC. 847 Holt Road Webster, NY 14580-9103 Phone: (716) 872-0010 Fax: (716) 872-0739 Toll Free (800) 828-6308 Internet: http://www.ashly.com 1997 by Ashly Audio Corporation. All rights reserved worldwide. Printed in USA 4/97 SRA Rev 3
