Parasound A 31 User Manual

A 31

Three Channel Amplifier

OWNER’S GUIDE

Important Safety Instructions

The lightning flash with the arrowhead symbol within an equilateral triangle is intended to alert the user to the
presence of “dangerous voltage” inside the product that may constitute a risk of electric shock.

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

TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER. NO USER-SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL

1. Read Instructions — Read all the safety and operating instructions before operating this product.

2. Retain Instructions — Retain safety and operating instructions for future reference.

3. Heed Warnings — Adhere to all warnings on the product and in the operating instructions.

4. Follow Instructions — Follow all operating and use instructions.

5. Cleaning — Unplug this product from the wall outlet before cleaning. Use a damp cloth for cleaning. Clean
the outside of the product only.

6. Attachments — Do not use attachments that are not recommended by the product manufacturer; they may
be hazardous.

7. Water and Moisture — Do not use this product near water.

8. Accessories — Do not place this product on an unstable cart or stand. The product may fall, causing bodily
injury and damage to the product. A product and cart combination should be moved with care. Quick stops,
excessive force, and uneven surfaces may cause the product and cart to overturn.

9. Ventilation — Slots and openings in the cabinet are provided for ventilation to ensure reliable operation of
the product and to protect it from overheating. These openings must not be blocked or covered. This product
should not be placed in a built-in installation such as a bookcase or rack unless proper ventilation is provided.

10. Power Sources — Operate this product only from the type of power source indicated on the label. If you are
not sure of the type of power supply to your home, consult your dealer or local power company. This product is
equipped with a three-prong grounding plug. This plug will only fit into a grounding power outlet. If you are unable
to insert the plug into the outlet, contact your electrician to replace your obsolete outlet. Do not defeat the safety
purpose of the grounding plug.

11. Power Cord Protection — Power supply cords should be routed so that they are not likely to be walked on or
pinched by items placed upon or against them.

12. Lightning — Unplug the unit from the wall outlet for added protection during a lightning storm and when it is
left unattended and unused for long periods of time. This will prevent damage to the product due to lightning and
power line surges.

13. Overloading — Do not overload wall outlets or extension cords. This can result in a fire or electric shock.

14. Inserting Objects into Unit — Never push objects of any kind into this product through any openings; they
may touch dangerous voltage points or short out parts that could result in fire or electric shock.

15. Servicing — Do not attempt to repair or service this product yourself. Opening or removing covers may expose
you to dangerous voltage and other hazards. Refer all servicing to qualified service personnel.

16. Damage Requiring Service — Unplug this product from the wall outlet and refer servicing to qualified
service personnel under the following conditions: a) If the power-supply cord or plug is damaged.
b) If liquid has been spilled into the product.
does not operate normally by following the operating instructions. e) If the product has been dropped or damaged
in any way. f) If the product exhibits a distinct change in performance.

17. Replacement Parts — When replacement parts are required, be sure the service technician has used
replacement parts specified by the manufacturer. Unauthorized substitutions may result in fire, electric shock, and
other hazards.

19. Safety Check — Upon completion of any service or repairs to this product, ask the service technician to
perform safety checks to determine that the product is in proper operating condition.

20. Wall or Ceiling Mounting — Mount the product to a wall or ceiling only as recommended.

21. Heat — The product should be situated away from heat sources such as radiators, heat registers, stoves,
and other products (including amplifiers) that produce heat.

c) If the product has been exposed to rain or water. d) If the product

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Table of Contents

Introduction ................................................. 4

Placement and Ventilation Guidelines .............................. 5

AC Mains Voltage ............................................. 5

Rack Mounting ............................................... 6

Audio Input and Output Connections .............................. 7

Gain Control Settings ......................................... 9

Turn On Options ............................................. 10

Front Panel Operation ......................................... 12

Technically Speaking ......................................... 13

Design Overview ............................................. 14

Problems and Remedies ....................................... 17

If You Require Assistance or Warranty Repair

Specifications ............................................... 19

...................... 18

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INTRODUCTION

Thank You for Choosing Parasound

Your new Parasound Halo A 31 power amplifier has been designed with the most advanced,
proven class A/AB amplifier technology. The A 31 is built to extremely strict quality and
performance standards for which Parasound is renowned. We’re proud to offer you this
exceptional audio component that will bring you many years of enjoyment and dependability. We
designed your new Halo Series A 31 Amplifier to perform at a higher level of sonic performance
than you may have expected and we encourage you to read this entire manual to maximize your
enjoyment. We wish you many years of listening enjoyment.

-The Parasound Staff

Keeping Records for Future Reference

Record the serial number located on the back panel or bottom of your A 31 in the space below.
Also note your Parasound Dealer’s name and telephone number. Your purchase receipt/bill of
sale is required to determine if your A 31 is eligible for Parasound warranty service. We
recommend that you make an extra copy of your original purchase receipt/bill of sale and store it
inside the A 31’s carton.

Parasound A 31 Amplifier Serial #: ______________ (5 digit number below the bar code)

Parasound Dealer: ___________________________________________________

Parasound Dealer Phone Number: ___________________

Date of Purchase: ______________________

Important Warranty information

There is no Parasound warranty for this unit if it was not purchased from an Authorized
Parasound Dealer. Investigate warranty coverage statements made by an unauthorized dealer

very carefully, as you will need to depend entirely upon your dealer, and NOT upon Parasound.
Unauthorized dealers lack the capability to make repairs or arrange for repairs of Parasound
equipment. A list of Authorized Parasound Dealers and detailed warranty information is available
at www.parasound.com or you can call 415-397-7100 between 8:30 am and 4 pm Pacific time.
A missing or altered serial number could indicate that this unit was re-sold by an unauthorized
dealer or is stolen merchandise. If this unit is missing its serial number or the serial number has
been altered, you should return it to your dealer immediately for a full refund.

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Unpacking Your A 31 & Placement Guidelines

Unpacking Your A 31

Carefully remove your A 31 from its shipping carton and locate the enclosed accessories:

• AC power cord

• Two trigger wires, one with 3.5 mm mini plugs, one with a 2.5mm and a 3.5mm mini plug

While you are unpacking your A 31, inspect it thoroughly for possible shipping damage and tell
your Parasound dealer immediately if you find any evidence of shipping damage.
This would be a good time to make a copy of your sales receipt to store with the A 31’s original
packing.
Note: Please save and store both the inner and outer cartons and, most especially, the foam
packing inserts to protect the A 31 if you have to move it or ship it. You may wish to flatten the
cardboard cartons to save room in storage after cutting the taped seams on the bottom flaps.

Placement Guidelines

The A 31 will be easier to use and will last longer if you follow these simple guidelines:

• Place the A 31 on a surface that will adequately support its substantial weight.

• Use input and output cables that are long enough to leave some slack; that will enable you to
pull the A 31 out of a cabinet to check or to change connections without inadvertently
disconnecting cables.

• The A 31 should never be placed in a completely enclosed cabinet

• Place your A 31 where you can route input and output signal cables as far as possible from
any AC cords.

• Where signal cables must cross AC cords they should do so only at a 90° right angle.

Ventilation Requirements

• Always position the A 31 horizontally.

• The A 31 should never be stacked above another power amplifier.

• Do not install the A 31 in an unventilated equipment cabinet or compartment. Pockets of
stagnant hot air can build up even in a cabinet with an open front and back. A ventilation fan
such as the Parasound Zbreeze is highly recommended to prevent “hot spots” in confined
spaces.

AC Mains Voltage

NOTE: Before you plug this amplifier into an AC mains outlet:

If you live in a region with 220V-230V AC mains:

Plugging this amplifier into a 220V-240V AC mains outlet when the unit is wired internally for
115V and its main fuse rated for 115V operation will severely damage it and could put you at risk
of personal injury. If you are unsure of the internal voltage setting for this amplifier you should
have a qualified electronics technician inspect it and change it as required.

AC Voltage Rewiring Technical Information

Parasound will provide technical information which pertains to the interior of this amplifier only to
a qualified electronics technician. This restriction is for your safety as well as the correct
functioning of your amplifier.

AC Voltage Warranty Exclusion

Amplifiers set for 115V which are damaged by 220V-240V are not covered under the Parasound
Limited Warranty.

Before Making Any Audio Connections

Always turn off your A 31 and disconnect the AC cord before making or changing any input,
output or trigger wire connections. Inserting or removing an input or output cable while the A 31
and your preamp are turned on can result in a blast of sound that can damage your
loudspeakers.

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Rack Mounting Your Parasound A 31

To mount the A 31 into a 19" wide equipment rack, you must first attach its two “L” shaped rack
mount brackets (included). With its four feet removed, the A 31 chassis and front panel height
occupies four rack spaces (7" or 176 mm). When mounting equipment below the A 31, you will
also need to allow about 1⁄8" below the unit for the bottom chassis screws.

To attach the rack mount brackets:

• Remove the three screws from each side of the A 31. These are arranged vertically, behind its
front panel and in front of its first heatsink fin.

• Line up the three holes on each bracket with the three holes on the A 31 and reinsert the
screws.

• Make sure the screws are tight because they will support the entire weight of the A 31 in the
equipment rack.

Note: Tighten each bolt just enough to keep the unit secure in the rack to avoid deforming the
shoulder washers. Eliminating metal-to-metal contact reduces the likelihood of creating a ground
loop that might introduce hum into your system.

A single standard rack space is 1-3⁄4" (44mm) high in a 19" wide equipment rack. This
measurement standard was developed by the EIA (Electronic Industries Association) so
manufacturers of electronic components and equipment racks could build products in
standardized heights that would fit in a uniform space. Please call your Parasound dealer or
Parasound Technical Services if you need additional advice about rack mounting the A 31.

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