Atlas Sound PA702 2 Channel 70W Power Amplifier Owner’s Manual

: June 17, 2024
: ATLAS Sound

Table of Contents

ATLAS SOUND PA702, 2-CHANNEL 70W POWER AMPLIFIER
OWNER’S MANUAL

ATLAS SOUND PA702, 2-CHANNEL 70W POWER AMPLIFIER

OWNER’S MANUAL

Atlas Sound PA702 2 Channel 70W Power Amplifier 1

ATLAS SOUND PA702, 2-CHANNEL 70W POWER AMPLIFIER

ULTRA COMPACT DESIGN WITH INTEGRATED VIDEO POLE MOUNT SUPPORT SYSTEM

ATTENTION

CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN

WARNING
TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK
DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.

The lightning flash with arrowhead symbol within an equilateral triangle, is intended to alert the user to the presence of uninsulated “dangerous voltage “ within the product’s enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons.

The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product.

IMPORTANT SAFETY INSTRUCTIONS

Read these instructions.
Keep these instructions.
Heed all warnings.
Follow all instructions.
Do not use this apparatus near water.
Clean only with dry cloth.
Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.
Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
Only use attachments/accessories specified by the manufacturer.
Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus. When a cart is used use caution when moving the cart/apparatus combination to avoid injury from tip-over.
Unplug this apparatus during lightning storms or when unused for long periods of time.
Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.
WARNING: To reduce the risk of fire or electric shock, this apparatus should not be exposed to rain or moisture and objects filled with liquids, such as vases, should not be placed on this apparatus.
To completely disconnect this equipment from the mains, disconnect the power supply cord plug from the receptacle.
The mains plug of the power supply cord shall remain readily operable.

WARNING WHEN THE DEVICE IS IN USE

To prevent electric shock, do not remove the product cover as there are high voltage components inside. Refer all servicing to Atlas Sound.
Should any of the following irregularities occur during use, immediately switch off the power, disconnect the power cord from the AC outlet and contact Atlas Sound. Do not to attempt to continue operation with the product as this may cause fire or electric shock:
• Smoke or strange smell coming from the unit.
• If the product falls or the case is damaged.
• If water or any metallic objects falls into the product.
• If the power supply cord is damaged in any way.
• If the unit is malfunctioning.
Do not insert or drop metallic objects or flammable materials into the ventilation holes of the product’s cover, as this may result in electric shock or fire.
Do not place any containers with liquid or metallic objects on the top of the product. If any liquid spills into the unit, fire or electric shock may result.
Never operate this product or touch the power supply cord during an electrical storm, electric shock may result.
Never exceed the wattage on the product when connecting equipment. Fire and/or property damage may result.
Operate the product only with the voltage specified on the unit. Fire and/or electric shock may result if a higher voltage is used.
Do not modify, kink, or cut the power cord. Do not place the power cord in close proximity to heaters and do not place heavy objects on the power cord, including the product itself, doing so may result in fire or electrical shock.
Replace the protective cover over the speaker terminals after installation. Do not touch the 70V speaker terminals as electric shock may result.
Ensure that the safety ground terminal is connected to a proper ground. Never connect the ground to a gas pipe as a catastrophic disaster may result.
Be sure the installation of the product is stable, avoid slanted surfaces as the product may fall and cause injury or property damage.

CAUTION When Installing the Product

Plugging in or unplugging the power cord with wet hands may result in electric shock.
Never move the unit with the power cord plugged into the wall, as damage to the power cord may result. When unplugging the cord from the wall, grasp the plug, NOT the cord.
Never install this product in humid or dusty locations, nor in direct sunlight, near sources of heat, or in areas where sooty smoke or steam are present. Fire and electric shock may result.
Keep all sides of the unit at least 3 ½” away from objects that may obstruct air flow to prevent the unit’s internal temperature rise.

CAUTION When the Product is in Use

When powering the product up for the first time, ensure that the level control is turned down. Unexpected high sound pressure levels may be present at the speakers and result in hearing loss.
Never place heavy objects on the product, causing it to fall and/or break, resulting in personal injury and property damage. In addition, the product itself may fall and cause injury and property damage.
Never operate the product for extended periods with the sound in a distorted condition. This is an indication of a malfunction, which may result in excessive heat being generated and causing a fire.
Contact Atlas Sound for instructions on cleaning the inside of the unit. Large accumulations of dust inside the unit may result in heat buildup and fire.
Ensure that the power supply plug is securely plugged into the wall outlet. Never allow dust to accumulate on the power plug or inside the wall outlet.
When cleaning the unit or the unit is not to be operated for an extended time period, unplug the power cord from the wall.

Introduction

Thank for purchasing the Atlas Sound PA702 amplifier. This new and innovative professional grade product has been designed from the ground up to include the important features that professional installation personnel require to meet or exceed their customer’s expectations. Small and compact, and engineered for reliability, the Atlas Sound PA702 will provide years of service and flexibility in today’s conferencing, background music and paging applications.

Key Features

70 Watt x 2, compact power amplifier
1RU tall by 1⁄2 rack wide
Ultra efficient amplification technology, convection cooled
Patent pending, through chassis mounting system for use with pole mounted projector systems
Energy efficient, only 16 watts draw in sleep mode
Current sense auto turn-on
Audio sense auto turn-on
Balanced inputs via Phoenix connector
Unbalanced inputs via RCA connectors, with separate level controls
Mix function for two source input
Unbalanced parallel combine
Screwdriver adjust level controls
Screwdriver adjustable tone controls
Rack mountable, single unit or dual units

Applications

The Atlas Sound PA702 amplifier can be used for a number of applications. This amplifier features an ultra compact design requiring only 1RU in height and 1⁄2 rack wide in space. The 70 watts per channel at 8 ohm gives the power to meet most amplifier demands. The patent pending thru hole chassis design makes it convenient to use with ceiling mounted video projectors. One or two units can be rack mounted also allowing it to be used in more traditional applications. Remote turn on is easily accomplished by either audio or AC adjustable trigger sensors. If focused power is required a optional Hi-pass filter is incorporated. The PA702 can be used for many in many ways ranging form boardroom, restaurant, commercial paging and back ground music applications.

Atlas Sound PA702 2 Channel 70W Power Amplifier 3

Front Panel

1. Power Switch
This switch turns the AC Mains power to the amplifier on or off.

2. Power LED
Illuminates Red when the power switch is depressed. Red means the amplifier has AC mains power to the unit and is standby or sleep mode. When LED is Blue the unit is active and will pass audio.

3. Limit LED
The Limit LED will illuminate Red if either channel of the PA702 reaches maximum output power or if a fault is detected with in the amplifier. The PA702 features a true limiter circuit which help prevents the amplifier from hard clipping or from being over driven. An occasional flash of the LED is OK, if the LED is on continuously reduce the input level of the amp. After the reducing the input level and the Limit LED remains on, recheck the load connections to the amp.

4. Left & Right Signal LED’s
The Signal LED’s illuminates Blue if there is audio signal present at the input of the amp.

5. Left & Right Input Gain
The Left and Right rotary control varies the amplitude of the signal fed into the amplifier. Turn clockwise to increase and counterclockwise to decrease the signal level.

6. Bass Control
Normally set at the 12:00 position unity gain, rotating clockwise will increase (boost) bass frequencies to a maximum of +6dB at 100Hz. Rotating counterclockwise from the 12:00 position will decrease (cut) bass frequencies to a maximum of -6dB at 100Hz. Note: This feature affects both the Left and Right Channels the same.

7. Treble Control
Normally set at the 12:00 position unity gain, rotating clockwise will increase (boost) treble frequencies to a maximum of +6dB at 10kHz. Rotating counterclockwise from the 12:00 position will decrease (cut) treble frequencies to a maximum of -6dB at 10kHz. Note: This feature affects both the Left and Right Channels the same.

Rear Panel

1. IEC AC Receptacle
Connect this grounded power cord to 120VAC circuits only. Serious damage may result otherwise.

2. AC Mains Fuse
For 100v – 120v operation use Slow Blow T3.15A 250v, 5mm x 20mm.

3. UNSWITCHED OUTLET
The un-switched outlet provides power for other devices such as video projectors, CD players or laptop computers. This AC outlet is live all the time as long as the power cord is plugged into a live duplex outlet. Keep the total power draw below 500W. This outlet can also be used to remotely turn on the PA702. See AC Sense Trigger for more detailed information (page 9).

4. RCA Input
Unbalanced signals are accepted when using the Left and Right RCA connectors. Note:On the bottom of the chassis there are level controls for the for the Left and Right RCA inputs. This allows you to adjust the level from OFF to +6dB. Factory settings calibrated for 320mv of input sensitivity. See Mixer Function page 9 for use.

5. Balanced Input Connections
Left and Right balanced input signals can be accomplished by wiring the removable Phoenix type connector per the labeling on the rear of the amp. Note: The middle pin is the common ground connection for both Left and Right input ground. For unbalanced signals connect the (–) and (GND) pins together.

6. Speaker Connections
A removable Phoenix type connector is supplied to connect your speakers to the PA702. It is recommended to use 16guage wire or higher for connection to the speaker. Note: Do not overload the amp by connecting to many speakers to the amp. Four ohms per channel is the maximum load.

7. Four Position Dip Switch Assignment
Switch 1 – Sense On / Off , this switch activates the PA702 remote turn on sensing circuits via either Audio or AC trigger. When the switch is in the “ UP ” position, all trigger circuits are bypassed. The only way to turn the amp On or Off is via the mains AC Power Switch located on the front panel. When in the “ DOWN ” position either the Audio or AC Sense turn on Triggers is activated. See switch 2 for selection.

Switch 2 – Sense AC / Audio , when Switch 1 is in the “ DOWN ” position you may select the type of remote turn on trigger. Note the AC Mains Power Switch must also be in the “ ON ’ position.

AC Trigger – This switch function is used if you have an external device is plugged into the Unswitched AC outlet and you want that device to turn on or activate the amplifier. The “ DOWN ” position of Switch 2 is for AC trigger, meaning if a device such as a projector is plugged into the Unswitched AC outlet and is turned on the AC trigger circuitry will sense current draw and turn on the PA702. See AC Sense control below for sensitivity adjustments.

Audio Trigger – This switch function is used if you have an external audio source plugged into either the RCA or Balanced inputs and you want that audio to turn on or activate the amplifier. If Switch 2 is in the “ UP ” position it is in Audio Sense mode. When audio is present at either the RCA or Balanced inputs, the trigger circuitry will turn on the PA702. See Audio Sense control below for sensitivity adjustments.

Switch 3 – Input Mono / Stereo Switch, this switch affects both the RCA and Balanced inputs. When this switch is in the “ UP ” position, only one input signal is needed to feed signal to both amplifier channels using the same signal. Note: the input sensitivity is reduced by 6dB in the “ MONO ” mode. When this switch is in the “ DOWN ” position, both input are separated and operate as “Stereo” mode.

Switch 4 – Hi Pass Filter In / Out, when this switch is in the “ UP ” position no input filter is applied. With the switch in the “ DOWN ” position a 100Hz 12db Hi-Pass filter is engaged at the input of each channel.

8. Audio Sense Trigger Adjustment – this potentiometer works when Dip Switch 1 is set to “ DOWN ” or “ SENSE ON ” position and Dip Switch 2 is in the “ UP ” or “ AUDIO ” position. By rotating the potentiometer clockwise (right) the trigger point becomes less sensitive to turn on, meaning it will take more audio signal at the input to turn on the amp. Note: Once the PA702 has sensed audio signal and has triggered on, it will take 15 -20 min for it revert back into sleep mode even when there is no audio present. The PA702 level controls have no affect on this feature.

9. AC Sense Trigger Adjustment – this potentiometer works when Dip Switch 1 is set to “ DOWN ” or “ SENSE ON ” position and Dip Switch 2 is in the “ DOWN ” or “ AC ” position. By rotating the potentiometer clockwise (right) the trigger point becomes less sensitive to turn on, meaning it will take more AC Current draw from the Unswitched AC outlet to turn on the amp. Note: When using the AC Sense mode between “ STANDBY OR SLEEP ” and “ ON ” is instantaneous as long as the AC Sense is set properly and the component plugged into the AC Unswitched socket is on drawing current.

MIXER FUNCTION

Bottom Chassis View

Left
Right
RCA Mix Level

The PA702 has incorporated a mixer function that allows you connect two different sources to the amp. The Left RCA unbalanced input the Left Balanced inputs are summed together and are electrically isolated from each other. The same is true for the Right inputs. Both RCA inputs have separate level controls and are Pre the Front panel Master Left & Right Level controls. This allows you to feed a balanced signal from one source and apply a second source signal to the unbalanced RCA input and adjust or mix the levels between the RCA unbalanced and balanced input via the RCA levels on the bottom of the amp. Then adjust the overall system level via the Front panel Master levels. A common application would be to feed a wireless microphone’s output signal to the balanced input (Note: If you may need to “Y” the signal if both channels are needed). Feed a CD or computer audio output to the RCA unbalance input. Adjust the RCA input level to the microphone level until you achieved the balanced you need and then adjust the master level to the room.

INSTALLATION AND CONSIDERATIONS

Cabling:
The PA702 can be used with either balanced or unbalanced sources, and the outputs can be used with either balanced or unbalanced loads, provided the proper cabling is used. A balanced line is defined as two-conductor shielded cable with the two center conductors carrying the same signal but of opposite polarity when referenced to ground. An unbalanced line is generally a single- conductor shielded cable with the center conductor carrying the signal and the shield at ground potential.

Balanced Input – Use 2 conductor w/shield for low level signals of 20-22 gauge is best. Maintain the proper polarity, + to +, – to – and shield to ground. Note: The ground center pin of the Phoenix connector is common for both channels.

Unbalanced inputs – For the RCA inputs pre-made RCA cables can be purchased from vendors to simplify interconnection to external devices. For unbalanced signals using the Phoenix connector connect the (–) pin of the amplifier input to the GND center pin and the (+) pin to the positive of the source.

Speaker outputs – Use 2 conductor unshielded wire of the appropriate gage. If you are unsure about this, contact Atlas Sound Tech Support at 1-800-876-3333. Make sure you know how many speakers you need and what load value you intend to use.

AC Sense Control Adjustment (Rear Panel)
The PA702 can be remotely turned on via the Unswitched AC Outlet. The PA702 mains power switch must be on to activate or adjust AC sense trigger control. Prior to powering on the AC mains switch follow the instructions below.

Dip Switch setting to “ SENSE ON ” and “ AC ON ”.
Then plug a video projector or audio component into the Unswitched AC socket on the rear of the PA702.
By using the potentiometer adjustment labeled “ AC SENSE ” rotate fully clockwise.
Turn on the AC Mains Power Switch of the PA702.
Turn on the device (video projector) that is plugged into the AC socket. If the PA702 power LED does not turn from Red to Blue the amp is still in sleep mode. Slowly rotate the potentiometer counter clockwise until the LED changes from Red to Blue. When Blue the amplifier will allow any audio that is at the audio inputs to be amplified.
For proper triggering check the operation by turning video projector or component on and off.. When the accessory component is turned off the AC mains power LED should turn Red immediately. If it remains Blue, slightly rotate the adjustment clockwise until the LED turns Red. By rotating the potentiometer clockwise (right) the trigger point becomes less sensitive to turn on, meaning it will take more AC Current draw from the Unswitched AC outlet to turn on the amp. Note: Some components have a small change in current draw and may be more difficult to set a proper AC trigger. In this case, “ AUDIO SENSE ” turn on may be an alternative option for better standby triggering stability.

Audio Sense Control Adjustment (Rear Panel)
The PA702 can be remotely turned on via the two stereo audio inputs. The PA702 mains power switch must be on to activate or adjust Audio Sense trigger control. Prior to power on the AC Mains Power Switch of the PA702 follow the instructions below. Note: Once the PA702 has sensed audio signal and has triggered on, it will take 15 -20 min for it revert back into sleep mode even when there is no audio present. Also, the PA702 level controls have no affect on this feature.

First select the proper Dip Switch setting to “ SENSE ON ” and “ AUDIO ON ”.
Set the PA702 front panel level controls to 12:00 o’clock position.
Then plug a audio component such as a computer, DVD player or CD player into the balanced or RCA unbalanced inputs of the PA702. Note: Prior to turning on the AC mains of the PA702 make sure the source level is turned fully down or off (Mute).
By using the potentiometer adjustment labeled “ AUDIO SENSE ”, rotate fully clockwise. The AC mains Power LED should be Red still.
Slowly apply audio signal from audio source until the AC Mains Power LED turns from Red to Blue. Whenever there is an audio signal present at the inputs, the PA702 automatically switches itself into from standby or sleep mode to amplifying the audio the signal into the room loudspeakers If the PA702 power LED does not turn from Red to Blue the amp is still in sleep mode. Slowly rotate the potentiometer counter clockwise with audio present until the LED changes from Red to Blue. If the adjustment is fully counter clockwise and the amp is still in sleep mode it may be necessary to increase the audio source output signal. Note: By rotating the potentiometer clockwise (right) the trigger point becomes less sensitive to turn on, meaning it will take more audio signal at the input to turn on the amp.
For proper audio triggering some experimentation may be necessary, but once it is set properly the PA702 will not need readjusting. Check the operation by turning audio source on and off. Note: If the sensitivity is set too high, random switching may occur as the unit senses the residual noise level and may falsely trigger. If this happens slightly rotate the potentiometer clockwise.
Adjust the amplifier level controls and audio source to the desired listening level.

Placement and mounting of the PA702
Turn off all equipment before making connections. Mount amplifier in a standard-width 19” rack. It can be mounted above or below anything that does not generate excessive heat. Although the unit’s chassis is shielded against radio frequency and electromagnetic interference, extremely high fields of RF and EMI should be avoided.

Ventilation – The appliance should be situated so that its location or position does not interfere with its proper ventilation. For example, the PA702 should not be situated on sealed cabinet or on a shelf with obstacles on it that may impede the flow of air through the ventilation openings. It is recommended that if the amp is not used in an open air pole mount that it be rack mounted into a commercial rack.

Heat – The PA702 should be situated away from heat sources such as radiators, heat registers, stoves, or other appliances (including amplifiers) that produce excessive heat. Ambient temperatures should not exceed 113° F (45°C) when equipment is in use.

Video Pole Mount – The PA702 is ideally suited to be used in board or class room video / audio applications. The PA702 incorporates a 2” diameter hole trough the center of the chassis to allow for sharing the same support pole that standard ceiling video projectors mount to. Enclosed with the PA702 is the support bracket and hardware to mount the PA702 to a pole. Follow the below instructions for proper installation.

Make sure the pole you are mounting the amp to does not exceed 2” or 51mm. Common pipe to use for video projector mounting is 1.5 ID plumbing pipe. The OD for this pipe is 1.9” or 49mm.
Make sure the PA702 is unplugged from the AC source.
Remove the top and bottom hole plugs.
Secure the pole support bracket using the four screws as shown in the diagram below. Note: the support bracket may be installed on the top or bottom of the amplifier.
Slide the amplifier up the pole. Do not force the amp onto the pole. Pay attention to orientation of the amp.
Secure clamp by tightening the two 1⁄2 clamps around the support bracket. Do not over tighten.
Once the PA702 is secured to the pole DO NOT mount any additional PA702s to the same bracket. The support bracket is only designed to support one PA702.

Pole Mount Pre Assembly

Pole Mount Final Assembly

SPECIFICATIONS

OUTPUT POWER
70 Watts per channel @ 8Ω
RMS 1% THD – 50 Watts per channel @ 4Ω

TOTAL HARMONIC DISTORTION
0.2%

FREQUENCY RESPONSE
+/-3dB 30Hz – 20 KHz No Hi-Pass Filter
+/-3dB 100Hz – 20KHz Hi-Pass engaged

PROTECTION CIRCUITS
AC fuse (T3.15A 250v 5mm x 20mm),
Thermal, short circuit

SIGNAL TO NOISE RATIO
-100dB below rated output (A-weighted)

INPUT SENSITIVITY
RCA Unbalanced 320mv
Balanced 320mv

INPUT IMPEDANCE
RCA Unbalanced10k
Balanced 20k

AUDIO TURN ON TRIGGER
1mv – 20mv

AC TURN ON TRIGGER
1mA -350mA

POWER REQUIREMENT
120 VAC, 60 Hz

POWER CONSUMPTION
16 watts Sleep Mode

DIMENSIONS
8.5” x 1 3/4” x 13.5”
(216mm x 45mm x 343mm)

WEIGHT
4.9lbs (2.4Kg) Unit

NOTES: __

Limited Warranty

All products manufactured by Atlas Sound are warranted to the original dealer/installer, industrial or commercial purchaser to be free from defects in material and workmanship and to be in compliance with our published specifications, if any. This warranty shall extend from the date of purchase for a period of three years on all Atlas Sound products, including SOUNDOLIER brand, and ATLAS SOUND brand products except as follows: one year on electronics and control systems; one year on replacement parts; and one year on Musician Series stands and related accessories. Additionally, fuses and lamps carry no warranty. Atlas Sound will solely at its discretion, replace at no charge or repair free of charge defective parts or products when the product has been applied and used in accordance with our published operation and installation instructions. We will not be responsible for defects caused by improper storage, misuse (including failure to provide reasonable and necessary maintenance), accident, abnormal atmospheres, water immersion, lightning discharge, or malfunctions when products have been modified or operated in excess of rated power, altered, serviced or installed in other than a workman like manner. The original sales invoice should be retained as evidence of purchase under the terms of this warranty. All warranty returns must comply with our returns policy set forth below. When products returned to Atlas Sound do not qualify for repair or replacement under our warranty, repairs may be performed at prevailing costs for material and labor unless there is included with the returned product(s) a written request for an estimate of repair costs before any nonwarranty work is performed. In the event of replacement or upon completion of repairs, return shipment will be made with the transportation charges collect.

EXCEPT TO THE EXTENT THAT APPLICABLE LAW PREVENTS THE LIMITATION OF CONSEQUENTIAL DAMAGES FOR PERSONAL INJURY, ATLAS SOUND SHALL NOT BE LIABLE IN TORT OR CONTRACT FOR ANY DIRECT, CONSEQUENTIAL OR INCIDENTAL LOSS OR DAMAGE ARISING OUT OF THE INSTALLATION, USE OR INABILITY TO USE THE PRODUCTS. THE ABOVE WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

Atlas Sound does not assume, or does it authorize any other person to assume or extend on its behalf, any other warranty, obligation, or liability. This warranty gives you specific legal rights and you may have other rights which vary from state to state.

SERVICE

Should your PA Series amplifier require service, please contact the Atlas Sound warranty department at 1-877-689-8055, ext. 277 to obtain an RA number.

Atlas Sound Tech Support can be reached at 1-800-876-3333.

Visit our website at www.AtlasSound.com to see other Atlas products

Specifications are subject to change without notice

AtlasSound.com

1601 JACK MCKAY BOULEVARD ENNIS, TEXAS 75119 U.S.A. • TELEPHONE: 800-876-3333 • FAX: 800-765-3435