Parasound A 51 User Manual
A 51 Amplifier
Owner’s Guide
Congratulations and Thank You for Choosing Parasound
Your new Parasound Halo Series A 51 power amplifier presents the latest advancements in
amplifier technology. The A 51 is built to the strict quality and performance standards set by
Parasound. We’re proud to offer you this exceptional audio component that will bring you
many years of enjoyment and dependability.
Here at Parasound, we design our products to perform at a higher level of flexibility and
sonic performance than you may have expected. We encourage you to read this entire manual to learn all the features and capabilities of your new Halo Series A 51 Amplifier.
If you’re eager to get up and running right away, simply follow the basic step-by-step
instructions to connect and operate the A 51. If you want to learn about some of the technical and design aspects of your A 51, refer to the Technically Speaking and Parasound A 51
Design Overview sections in the back of the manual. If you run into difficulties, the
Troubleshooting Guide should help you quickly remedy the problem.
We appreciate you taking the time to read these instructions and thank you for selecting
Parasound for your listening pleasure.
The Parasound Staff
Unpacking Your A 51
Unpack your A 51 from the shipping carton, remove the enclosed rack mount brackets,
banana plugs for your speaker wires, AC power cord, and the control wire with a small plug
at each end. (This is the trigger connection wire). While you are unpacking your new amplifier, inspect it thoroughly for possible shipping damage. If you see any, contact your
Parasound dealer right away. Be sure to save and store both the inner and outer cartons and
the packing inserts for possible future transport. To save room for storage, you can cut the
seams on the bottom of the cartons and flatten them.
Keeping Records for Future Reference
Record the serial number located on the bottom of your A 51 in the space below. Also note
your Parasound Dealer’s name and phone number. We recommend that you keep your pur-
chase receipt with this manual and store them both in a safe place. You may need to refer
to this
information sometime in the future.
Parasound A 51 Amplifier Serial #: __________________________________________________
Parasound Dealer: ________________________________________________________________
Phone Number: __________________________________________________________________
Date of Purchase: ________________________________________________________________
THANK YOU!
YOU SHOULD KNOW
There is no Parasound warranty for this unit if it was not purchased from an
Authorized Parasound Dealer. Investigate any warranty claims made by unauthorized
dealers very carefully as you will need to depend entirely upon the dealer, and NOT
upon Parasound. Unauthorized dealers may lack the capability to arrange repairs of
Parasound equipment. Authorized Parasound Dealers are listed at
www.parasound.com or you can call
415-397-7100 between 8:30 am and 4:30 pm Pacific time.
A missing or tampered serial number could indicate that this unit was stolen or sold
by an unauthorized dealer. If this unit is missing its serial number, you should return
it to your dealer immediately for a full refund.
TABLE OF CONTENTS
A 51 Amplifier
PLACEMENT GUIDELINES FOR YOUR A 51 2
CONNECTING A SURROUND CONTROLLER
TO THE BALANCED INPUTS ON YOUR A 51 3
CONNECTING A SURROUND CONTROLLER
TO THE UNBALANCED INPUTS ON YOUR A 51 4
CONNECTING YOUR SPEAKERS TO THE A 51 5
MANUAL AND AUTOMATIC TURN ON-OFF OPTIONS 6
CONNECTING AN EXTERNAL DC SOURCE FOR AUTOMATIC ON-OFF 7
UNDERSTANDING THE INDICATORS ON THE A 51 8
CONNECTING THE AC POWER CORD 9
MAINTAINING YOUR A 51 10
TROUBLESHOOTING GUIDE 11
SERVICING YOUR A 51 12
TECHNICALLY SPEAKING 13
PARASOUND A 51 DESIGN OVERVIEW 15
PARASOUND A 51 SPECIFICATIONS 17
PLACEMENT GUIDELINES FOR YOUR A 51
Power amplifiers are usually heavier and generate more heat than other components. To avoid
damage to the A 51 or other equipment and to reduce risk of fire, you must follow these guidelines:
•
A cable with a 2.5 mm sub-mini plug on each end (provided).
•
Place the A 51 on a separate shelf that will adequately support its weight.
•
Keep it away from heat sources such as air ducts or radiators.
•
Avoid placing it on carpeting or another material that might obstruct airflow into the openings
in the chassis bottom.
•
Leave at least 3" of space around both sides and 6" of space above the top. The bottom clearance can be a little less.
•
Do not block the front of the A 51 behind closed cabinet doors during use.
•
Do not stack the A 51 with other components inside a cabinet unless you use a fan to circulate
and exhaust the warm air that builds up between them.
Rack Mounting Your Parasound A 51
To mount the A 51 into a 19" wide equipment rack, you must first attach its rack mount brackets
(provided). With its four feet removed, the A 51 chassis and front panel height occupies four
rack spaces (7" or 176 mm). When mounting equipment below the A 51, you will also need to
allow about 1⁄8" below the unit for the bottom chassis screws. A single standard rack space
allows 13⁄4" vertical height in a 19" wide equipment rack. This measurement standard was devel-
oped 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 51.
To attach the rack mount brackets:
•
Remove the three screws from each side of the A 51. 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 51 and reinsert the screws.
•
Make sure the screws are tight because they will support the entire weight of the A 51 in the
equipment rack.
2
LU CA SF ILMLM
On-Off Hi Temp
Amplifier A 51
Rack Bracket
CONNECTING A SURROUND CONTROLLER
TO THE BALANCED INPUTS ON YOUR A 51
Left and Right Balanced Input Jacks
Balanced connections will give you the best sound. If your surround controller has balanced
XLR output jacks, we recommend that you connect them to these inputs. Refer to the Balanced
and Unbalanced Lines in the Technically Speaking section for additional information about why
we recommend using balanced lines.
What You’ll Need:
•
Five balanced interconnect cables with XLR connectors
•
A surround controller with balanced output connectors
Before Connecting
❑ Leave the A 51’s AC cord disconnected until you have made all other connections to prevent
any surprise burst of sound.
❑ Make sure that all your cables are long enough so they are not strained or stretched once they
are connected.
❑ Make sure the Balanced - Unbalanced Input Select switch on the rear of the A 51 is in its
Balanced (left) position and the Ground switch is in its Normal (down) position.
To Connect
1 Plug the male end of the first balanced interconnect cable into the Balanced Ch 1 input
jack on the A 51.
2
Plug the female end of the cable into the balanced output jack for the channel on your
surround controller that you wish to correspond to Ch 1 on your A 51.
3
– 0 Repeat steps 1 and 2 above to connect Ch 2, Ch 3, Ch 4, and Ch 5.
3
LM
YOU SHOULD KNOW
Balanced XLR Jacks and Their Pin Configuration
The balanced inputs of the A 51 use XLR jacks that conform to the industry standard of:
Pin 1: Ground, Pin 2: Positive (+), Pin 3: Negative (--). The balanced outputs on some
components use terminals with 3 screws instead of XLR jacks. These are compatible
with the A 51 as long as you match the bare wires to the corresponding pins on the XLR
plug: + to pin 2, - to pin 3, and Ground to pin 1.
XLR Connectors
Male
Female
Input Select Switch,
set to left position
Input Select
1
3
5
7
9
Input
Balanced Unbalanced
Audio
Man
50 mV 250
12 V
Auto Turn On
A51 Amplifier
Parasound Products, Inc.
San Francisco, CA USA
L UC AS F I LM
Manufactured under
license from Lucasfilm
Ltd. Lucasfilm and THX
are registered Trademarks
of Lucasfilm Ltd.
WARNING
To Prevent Fire Or Shock
Hazard, Do Not Expose This
Unit To Rain Or Moisture.
CAUTION
To Prevent Electric Shock,
Do Not Remove Cover. No
User-Serviceable Parts Inside,
Refer Servicing To Qualified
Service Personnel.
2 4 6 8 10
OUTPUTS
Ch 1
Ch 2
Ch 3
Ch 4
Ch 5
Lift
Normal
Sensitivity
Ground
Ground Switch, set to down position
Fuse
T15A/250V1-115V Area
T8A/250V-230V Area
AC 115V 60Hz
AC 230V 50Hz
Power Consumption: 1800W
SURROUNDŁ
CONTROLLER
CONNECTING A SURROUND CONTROLLER
TO THE UNBALANCED INPUTS ON YOUR A 51
Ch 1-5 Unbalanced Inputs
Use these inputs if your surround controller doesn’t have balanced output connectors or if you
simply prefer to use unbalanced connections.
What You’ll Need:
•
Five shielded interconnect cables with RCA plugs
•
A surround controller with five RCA output jacks
Before Connecting
❑ Leave the AC cord on the A 51 disconnected until you have made all other connections to
prevent any surprise burst of sound.
❑ Make sure that all your cables are long enough so they are not pulled or stretched once
they are connected.
❑ Make sure the Balanced-Unbalanced Input Select switch on the A 51 is in its Unbalanced (right)
position and the Ground switch is in its Normal (down) position.
To Connect
1 Plug one end of the cable into the Unbalanced Ch 1 Input jack on the A 51.
2 Plug the other end of the cable into the unbalanced output jack for the channel on your
surround controller that you wish to correspond to Ch 1 on your A 51.
3
– 0 Repeat steps 1 and 2 for Ch 2, Ch 3, Ch 4, and Ch 5.
4
SURROUNDŁ
CONTROLLER
OUTPUTS
2 4 6 8 10
Parasound Products, Inc.
San Francisco, CA USA
Manufactured under
license from Lucasfilm
Ltd. Lucasfilm and THX
are registered Trademarks
of Lucasfilm Ltd.
CAUTION
To Prevent Electric Shock,
Do Not Remove Cover. No
User-Serviceable Parts Inside,
Refer Servicing To Qualified
Service Personnel.
L UC AS F I LMLM
A51 Amplifier
WARNING
To Prevent Fire Or Shock
Hazard, Do Not Expose This
Unit To Rain Or Moisture.
AC 115V 60Hz
AC 230V 50Hz
Power Consumption: 1800W
Input
12 V
Man
Audio
50 mV 250
Ground
Normal
Lift
Auto Turn On
Sensitivity
Fuse
T15A/250V1-115V Area
T8A/250V-230V Area
Ch 1
Ch 2
Ch 3
Ch 4
Ch 5
Balanced Unbalanced
Input Select
1
3
5
7
9
Ground Switch, set to down position
Input Select Switch,
set to right position
YOU SHOULD KNOW
Write Down Your Connections
Make a note of which channel on your surround controller now connects to each channel
of the A 51 so you’ll always hear the channels in their intended position and to facilitate
trouble-shooting in case you encounter a problem later on.
RCA Plugs
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