Stewart Audio DA-70-2 Owner's Manual

Da-70 series professional power amplifiers
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DA-70 Series
Professional Power
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Owners Manual

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Summary of Contents for Stewart Audio DA-70-2

  • Page 1: Owners Manual

    DA-70 Series Professional Power Amplifiers Owners Manual...
  • Page 2 Safety Before using your Stewart Audio Power Amplifier, please read this owner’s manual carefully to ensure optimum trouble-free performance. Warning: To REDUCE THE RISK OF ELECTRICAL SHOCK, DO NOT EXPOSE THIS AMPLIFIER TO RAIN OR MOISTURE. DANGEROUS HIGH VOLTAGES ARE PRESENT INSIDE THE CHASSIS.
  • Page 3: Important Safety Instructions

    - Important Safety Instructions - Please Read Prior to Product Installation. All of the safety and operating instructions should be read be- fore the amplifier is operated. Retain these instructions for fu- ture reference. All instructions should be followed; all warnings on the amplifier and in the operating instructions should be ad- hered to.
  • Page 4 The DA-70 Series Amplifiers are convection cooled and require no noisy fans for cooling. We at Stewart Audio strive to bring you the finest in professional electronics, and we thank you for your choice, which we see as an appreciation for our efforts.
  • Page 5: Table Of Contents

    Contents Special Features……………………………………………….……...…6 Front Panel Features……………………………..…………….…...10 Rear panel Features …………………………………………….…… 11 Installation……………………………………………………………...….12 Troubleshooting………………………………………………………..15 Technical Information………………………………………………...17 For The Record In the spaces below, record the Model, Serial number and Purchase information of your Power Amplifier. Model Number: ____________ Serial Number: ____________ Purchase Date: ____________ Purchased From: ___________ Retain this information for future reference.
  • Page 6: Special Features

    Special Features Stewart Audio’s new “Compact Series” Power Amplifiers utilizes the latest in Digital Au- dio Technology. The new, all Digital DA Series Power Amplifiers were developed by Stew- art Audio’s Digital Audio Team and represent the pinnacle of Stewart Audio technology and design.
  • Page 7 What is Damped Ternary Modulation? Conventional Class D amplifiers utilize binary, or BI-state operation. Bi- nary consists of only two switching states, positive power and negative power. Ternary, or tri-state operation, consists of three switching states; positive, negative and a zero power state. The third state is unique to this design.
  • Page 8 The Power Supply The foundation of all amplifier design is the power supply. For years Stewart Audio has pioneered leading edge, power supply technology. All Stewart Audio amplifiers feature a High-Frequency Switch Mode Power Supply. Because of this use of advanced technology some explanation is in order.
  • Page 9 AC line. The benefits are reduced heat dissipation, and downsizing of most major components. This saves space and weight without sacrificing the Sonic excellence Stewart Audio is famous for. Bridging Bridging of the DA-70 Series is not possible due to the high...
  • Page 10: Front Panel Features

    The DA-70 Series amplifiers employ circuitry which fully protect the ampli- fier while avoiding sonic compromise. Front Panel Simplicity is a design objective in the development of all Stewart Audio power amplifiers. These amplifiers remain simple and intuitive to operate even while incorporating some of the most advanced technology available today.
  • Page 11: Rear Panel Features

    All DA-70 Series amplifiers are equipped with a IEC socket on the rear apron for AC connections. Models DA-70-2 and DA-70-4 may only be connected to 120VAC mains. Models DA-70-2-PFC and DA-70-4-PFC are Power Factor Corrected and may be connected to any AC main voltage from 90VAC-240VAC.
  • Page 12: Installation

    NOTE: A –4 model (4 channel) amplifier will dissipate twice the heat of a –2 model (2 channel) amplifier and a PFC model will dissipate approximately 10% more heat than a non PFC model Therefore while a DA-70-2 runs very cool, the DA-70-4-PFC will require a little more attention to cooling.
  • Page 13 Under no circumstances should the amplifier be placed directly on carpeting or similar surfaces. AC Power Considerations Your Stewart Audio DA-70-2 and DA-70-4 amplifiers are designed to operate on 120 volt, 60 Hz AC current. Your Stewart Audio DA-70-2-PFC and DA-70-4-PFC amplifiers are designed to operate over a range of 90 volts - 240 volts, 50-60 Hz alternating current.
  • Page 14 Do not tie any output pin to any other pin or to ground. Never con- nect any speaker terminal to anything other than a single output pin. WARNING: Violation of this Caution may result in damage to your amplifier and will void your Stewart Audio Warranty.
  • Page 15: Troubleshooting

    Return Authorization (RA) Number and shipping instructions. Once an RA Number is obtained, return the unit to Stewart Audio at the address indicated on the RA Form. Refer to the enclosed Warranty information for Terms and Conditions of Warranty.
  • Page 16 Troubleshooting Reference Chart Symptom: Recommended Action: No output Power indicator is off. Be sure power outlet is “live” Be (There is a normal delay of up to 30 sure power switch is “on.” seconds on turn-on.) No output Power indicator LED cy- This indicates a short-circuit condi- cles on and off.
  • Page 17: Technical Information

    Specifications 8 Ohm Stereo Power 35 Watts/Ch 4 Ohm Stereo Power 70 Watts/Ch Frequency Response (+0, –0.5 dB, 20 Hz—20 kHz Full Power Bandwidth (20-Hz-20 kHz) ± .7 dB Signal to Noise >93 dB THD+N < .25% Input Sensitivity 1V (0 dBV) Standard Voltage Gain 17X (25 dB) Input impedance (Balanced / Unbal- 20k Ohms / 5k Ohms...
  • Page 18 Notes: Stewart Audio 1000 Technology Drive Columbia, Ca 95310 Tel: 209.588.8111 Fax: 209.588.8113 www.Stewartaudio.com...

This manual is also suitable for:

Da-70-4Da-70-2-pfcDa-70-4-pfc

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