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Operating Manual - SRA-120 Power Amplifier

4

1.

INTRODUCTION

Congratulations on your purchase of the  Ashly

SRA-120 professional stereo power amplifier.  This single
rack-space (1 3/4" height) amplifier delivers a substan-
tial amount of power with exceptional audio quality and
many features typically found only in larger power am-
plifiers,

Both channels of the SRA-120 can easily drive 4

ohm loads, delivering a total of 120 watts of undistorted,
average sinewave power.

The amplifier has an automatic output turn-on

delay and instantaneous output turn-off to protect speak-
ers from transients.  Each output will also turn off if it
"sees" a load of 2 ohms down to a short circuit.  The out-
puts are also independently protected from overheat con-
ditions.  Each channel will automatically reset itself from
any of these protection modes independent of the other
channel's operation.

The SRA-120 provides front panel level controls,

a stereo headphone jack, and six status LED's for ease of
control and monitoring.   The back panel provides both
balanced 1/4" jacks and balanced screw terminal inputs.
Three push-button switches allow selection of stereo,
mono, bridged mode, and input sensitivity, allowing the
amplifier to be applied in any configuration.   The
amplifier's signal ground can also be lifted from chassis
ground via a barrier strip jumper.

2.

UNPACKING

As a part of our system of quality control, every

Ashly product is carefully inspected before leaving the
factory to ensure flawless appearance.  After unpacking,
please inspect for any physical damage.  Save the ship-
ping carton and all packing materials, as they were care-
fully designed to reduce to minimum the possibility of
transportation damage should the unit again require pack-
ing and shipping.  In the event that damage has occurred,
immediately notify your dealer so that a written claim to
cover the damages can be initiated.

The right to any claim against a public carrier

can be forfeited if the carrier is not notified promptly and
if the shipping carton and packing materials are not avail-
able for inspection by the carrier.  Save all packing mate-
rials until the claim has been settled.

3.

AC POWER REQUIREMENTS

3.1

Voltage Requirements

Your SRA-120 amplifier is supplied with a three

conductor grounded  AC power cord, and should be
plugged into a standard 3-wire grounded electrical outlet
which supplies 120VAC 50-60 Hz (some export models
are wired for 100 or 240 volts and are labeled as such).
In the event of line voltage sag, or “brown-out”, SRA-
120 amplifiers will continue to operate normally, albeit
with less power.

3.2

Current Requirements

The actual AC current consumption by the am-

plifier depends greatly on the audio signal and the load
impedance.  For typical audio program material with the
SRA-120 driving both channels just peaking at the clip-
ping level, the following AC line current is drawn and
should be used for system design purposes:

Idle

0.1A

8

 loads

0.6 Amps

4

 loads

1.0 Amps

Table 3.1:  Estimated Maximum RMS  AC Line Current
Draw

3.3

AC Grounding Requirements

To reduce the risk of ground loop hum, all sys-

tem ground references should originate at the same point
in your  AC power distribution. Never remove the
amplifier’s ground pin as it is both unlawful and danger-
ous, creating a potential shock hazard.

4.

CABLE REQUIREMENTS

4.1

Input Cables

Be sure to use shielded cable whether balanced

or unbalanced.  Shielding which is properly grounded will
protect the signal from outside electrical interference such
as RF, fluorescent lighting, even computer noise.   As a
general rule, unbalanced or single-ended (tip-sleeve) lines
of less than 10 feet are satisfactory, but greater distances
may require a balanced signal.  Avoid running input lines
in close proximity or parallel to long speaker lines, AC
power cables, or power transformers, as this may gener-
ate hum or oscillation.

Summary of Contents for SRA-120

Page 1: ...0 828 6308 Fax 716 872 0739 Internet http www ashly com SRA 120 Power Amplifier Operating Manual SRA 120 SRA 120 Sig Clip SRA 120 Stereo Power Amplifier Protect Sig Clip Stereo Headphones Channel 1 Mo...

Page 2: ...2 Cooling 5 5 3 Grounding 5 5 4 Security Cover 5 6 FRONT PANEL FEATURES 6 6 1 Power Switch 6 6 2 Level Controls 6 6 3 Signal Present Indicators 6 6 4 Clipping Indicators 6 6 5 Protect Indicators 6 6...

Page 3: ...THEORY 10 10 TROUBLESHOOTING TIPS 10 10 1 No Sound 10 10 2 Distorted Sound 10 10 3 Excessive Hiss Noise 11 10 4 Excessive Hum Noise 11 11 DIMENSIONS 11 12 SPECIFICATIONS 12 13 WARRANTY POLICY 12 14 S...

Page 4: ...written claim to cover the damages can be initiated The right to any claim against a public carrier can be forfeited if the carrier is not notified promptly and if the shipping carton and packing mat...

Page 5: ...conductor cable 5 RACK MOUNTING REQUIREMENTS 5 1 Mechanical All Ashly amps are designed to fit in standard 19 inch racks Avoid placing the amp immediately next to devices which are sensitive to heat...

Page 6: ...ER SERVICING TO QUALIFIED SERVICE PERSONNEL TO REDUCE THE RISK OF FIRE REPLACE ONLY WI TH SAME TYPE FUSE TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE A...

Page 7: ...gnal Input Ground The CHASSIS GROUND terminal is internally connected to the chassis the AC earth ground and the power amplifier s signal ground The INPUT GROUND terminal is tied to the 1 4 jack s sle...

Page 8: ...nnel 1 output is switched out of phase with it s input In BRIDGED mode the channel 2 red bind ing post becomes the in phase speaker output terminal and the channel 1 red binding post becomes the out o...

Page 9: ...in the maximum amount of power when amplifying a mono signal In this mode the channel 1 input feeds both sides of the amp but the phase of channel 1 is inverted so the voltage difference between the c...

Page 10: ...tput level meters indicate 0dB level red CLIP LED on Amplifier is being clipped Reduce the signal level at the signal source 10 TROUBLESHOOTING TIPS 10 1 No Audio Output Power switch is on but not ill...

Page 11: ...source which feeds into the amplifier If excessive hiss noise is still heard then a noisy signal is being fed into the SRA 120 Isolate which piece of equipment in the audio chain is causing the noise...

Page 12: ...C 50 60Hz 240V Available 12 14 Shipping Weight 20 lbs Specification conditions are 120VAC 60Hz at 25 C 13 WARRANTY POLICY We thank you for your expression of confidence in Ashly products The unit you...

Page 13: ...13 Operating Manual SRA 120 Power Amplifier 14 SCHEMATICS Figure 15 1 SRA 120 Block Diagram and Wiring Diagram...

Page 14: ...Operating Manual SRA 120 Power Amplifier 14 Figure 15 2 SRA 120 Channel One Schematic Diagram...

Page 15: ...15 Operating Manual SRA 120 Power Amplifier Figure 15 3 SRA 120 Channel Two Schematic Diagram...

Page 16: ...ing 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 Corpor...

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