Audio Research Definition Series User manual

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Owner’s Manual
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Definition Series
DS450
Stereo Amplifier
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Contents
Model DS450 Stereo Amplifier
Illustrations 3
Preface 4
Warnings 4
Packaging 4
Unpacking 4
Accessories 4
Description of Controls 4
Connections 5
Single-Ended Operation 5
Balanced Operation 5
Installation 6
Remote Turn-on Connections 6
Operating Procedure 6
Start-Up Following ‘Protect’ Shutdown 7
Servicing 7
Cleaning 7
Disposal and Recycling Guidelines 7
Limited Warranty 8
Specifications 8
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Preface
Please take time to carefully read and
understand the following instructions before
you install or attempt to operate this
equipment. Becoming familiar with the
product and its correct operating
procedures will help assure you of maximum
musical enjoyment and reliable operation.
The effort you invest now will be well
rewarded in the years ahead.
Warnings
1.DO NOT POWER ‘ON’ THIS
AMPLIFIER WITHOUT INPUTS OR
SPEAKER LOAD CONNECTED TO
IT.
2.To prevent fire or shock hazard, do not
expose this product to rain or moisture.
3.This unit operates on voltages which can
cause serious injury or death. Do not
operate with covers removed. Any
necessary servicing should be carried out
by your authorized Audio Research dealer
or other qualified personnel.
4.The 12-gauge, 3-conductor power cord
on this unit is equipped with a standard 3-
prong grounding plug. If used normally, it
will provide a safe earth ground
connection of the chassis. Refer to section
on ‘AC Power Connections’ for detailed
information.
5.For safe operation and protection against
fire hazard, replace fuses only with those
of the same type and rating of fuses as
specified.
Packaging
Save all packaging accompanying this
product. You have purchased a precision
electronic instrument, and it should be
properly cartoned any time shipment
becomes necessary. It is very possible that
this unit could be damaged during shipment
if repackaged in cartoning other than that
designed for it. The original packaging
materials help protect your investment from
unnecessary damage, delay and added
expense whenever shipment of this unit is
required.
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Unpacking
The DS450 is packed within two cartons
(inner and outer) which have foam supports
in between. Because of the weight of the
unit and because it is a precision electronic
instrument it is necessary to take reasonable
care during unpacking and preparation for
use.
It is best to have a large, open work area
with available help. Set the carton upright in
the center of the work area and with a small
knife carefully slit the taped edges of the
outer carton's top flaps. Fold the flaps to the
sides and while holding the inner carton in
place, roll the unit upside down. You can
now lift the outer carton off and set it and
the filler panels aside. Now slit the inner
carton's taped seams on the bottom (now
facing upward). Again, fold the flaps over
and while holding the unit in, roll it over as
before. You can now lift the inner carton off
to find your DS450 sitting upright,
undamaged and uncartoned. Carefully
remove the plastic wrap. Now, while it is
fresh in your mind, reassemble the carton
system for future use.
Accessories
Spare Line Fuses:
2 – 10 Amp MDA slo-blo (100 & 120v)
2 – T6.3A Amp Super-Time-Lag TT (220 -240V)
Description of Controls
The front panel has:
1 Power line On-Off switch
1 Power ‘On’ LED (Green) indicator
POWER ON-OFF SWITCH: Press the power
switch to initiate or terminate AC line power
to the amplifier. When the LED is illuminated
the amp is ‘on’ and ready to play.

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Connections!
The rear panel has:
2 – RCA input connectors, for single-ended
connections, L & R
2 – XLR input connectors, for balanced
connection, L & R
4 – Output binding posts, (+) and (-), L & R
1 – Power line fuseholder
1 – Power line cord IEC connector for
removable 20A power cord (supplied)
2 – 12V remote start in and out jacks
2 – Switches for XLR or RCA input operation,
L & R
IMPORTANT: Use the best available speaker
wires and interconnects. As your system
improves in resolution from the addition of
quality components, it becomes
increasingly important to avoid the
limitations of inferior system
interconnections.
It is important sonically that your entire
system be connected so that the audio
signal arriving at the speakers has correct
absolute polarity or phase (i.e. is not
inverted).
Connect the black or (-) speaker terminal to
the wire that connects to the appropriate
channel (-) binding post on the amplifier.
Connect the red or (+) speaker terminal to
the wire that connects to the appropriate-
channel (+) binding post on the DS450. Using
the knurled black knob, tighten the binding
posts firmly to assure good contact for best
sonic results.
For bi-wired loudspeaker systems (i.e.
running separate wires to bass and treble
speaker terminals), simply repeat the above
instructions, taking care that all connections
have the same (+) or (-) polarity.
AC POWER CONNECTIONS: It is essential that
the DS450 amplifier be connected to a wall
AC power receptacle, or a similar heavy-
duty source. If it is connected to
convenience receptacles on preamplifiers,
etc., the full sonic capabilities of both the
amplifier and the preamplifier will be
compromised. The AC power source for the
amplifier should be capable of supplying 15
amperes for 100 or 120 volt units, or 8
amperes for 220 or 240 volt units.
For the very best performance on domestic
100 or 120 volt circuits, the DS450 should be
connected to its own AC power circuit
branch protected by a 15 amp breaker. The
preamplifier and other audio equipment
should be connected to a different power
circuit and breaker. Avoid the use
of extension cords. If they must be used on a
temporary basis, use 14-gauge or heavier
cords.
The DS450 utilizes a compatible grounding
system that generally does not require a
ground lifter adapter plug on the AC power
cord to minimize hum. The power cord on
your DS450 has a standard three-prong
grounding plug to provide maximum safety
when it is connected to a grounded wall
receptacle. If there is any question
regarding the safety of grounding
procedures, be certain to seek competent
help with the installation. Do not substitute a
lighter gauge power cord for the one
supplied with this unit.
If an electronic crossover or other AC
powered equipment is used with the
amplifier it may be necessary to use ‘ground
lifter’ adapters on the power plugs of that
equipment to minimize system hum.
Generally, the lowest hum is achieved when
the only direct connection between audio
common ‘ground’ and true earth ground
occurs in the preamplifier, through its
grounded power cord. Other equipment in
the system should have some form of
isolation to prevent ground loops and
associated hum.
Single-Ended Operation
Single-ended inputs should be used with a
preamplifier (or electronic crossover, etc.)
having single-ended outputs which does not
invert overall phase or polarity. When using
single-ended inputs, set two rear-panel
toggles to SE position. Disconnect any
balanced cables.
Balanced Operation
Balanced inputs can be used with a
preamplifier (or electronic crossover, etc.)
having balanced outputs. When using the
balanced inputs, set two rear-panel toggles
to BAL position. Disconnect any single-
ended cables.

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Installation
The amplifier may be installed in a
ventilated cabinet; observe the following
guidelines to maximize the performance
and service of your amplifier.
With proper installation, the DS450 may be
left on continuously for maximum
performance on demand; it will draw
approximately 55 watts of AC power at idle.
However, the DS450 has been designed and
engineered to minimize any ‘warm up’
necessary for best sonics; generally, a half-
hour or 45 minutes of actual playing time will
bring the amplifier around to more than
acceptable performance levels, with some
additional improvement noticeable over
the next hour or two. Warm-up
characteristics will depend upon ambient
room temperature at start-up, the nature of
the installation and the resolving power of
the associated equipment.
Operate the DS450 only in a horizontal
(upright) position. Adequate airflow and
proper cooling can be maintained only if
there is no restriction around the unit.
The five (5) non-marring feet provide
adequate spacing and mechanical
damping only from a smooth, hard surface.
Never operate the unit while it is sitting on a
soft, irregular surface such as a rug or
carpet.
If the unit is to be operated in an enclosure
such as an equipment rack, make certain
that adequate airflow above and below
the unit is provided. The ‘ambient’ operating
temperature should never exceed 120º F or
49º C. Improper installation will cause
premature component failure and will
affect your warranty, as well as the service
life of the unit.
It is normal for the DS450 power amplifier to
run lightly to moderately warm to the touch.
All components within are operated at safe,
conservative levels and will not be
improperly affected, providing the
requirements outlined above are adhered
to.
Remote Turn-on Connections
The DS450 has a built-in 12VDC remote turn-
on/off circuit for operation by a master
control system in a home theater or large
audio system. Use a 3.5mm (.140") diameter
mini plug to connect to the +12V IN jack on
the rear of the DS450. Two identical
paralleled jacks are provided to allow
chaining connections to control two or
more DS450s or other equipment.
The +12V IN jack should be connected to
the +12VDC output of the master control
system, using a continuous +12VDC signal at
20mA per DS450 for the duration of amplifier
on-time. Do not use a momentary or data
pulse control signal.
The front power switch on the DS450 must
be off to use the remote turn-on. Front
power switch is disabled when 12 volt trigger
is energized. The front power switch will not
turn the DS450 off if the 12 volt trigger is
energized.
The +12VDC remote jacks have polarity
protection, so they will not operate if a
-12VDC signal is accidentally connected, or
if the control wires are reversed.
Operating Procedure
1.Make sure you have read and followed
the INSTALLATION and CONNECTION
instructions prior to attempting operation.
2.Secure all rear panel connections
between DS450, and input source, and
loudspeakers.
3.Make sure the amplifier is properly
connected to a high current AC power
receptacle via the supplied power cord
(see CONNECTIONS).
4.Your preamplifier should be ‘On’ and
muted and/or set at minimum gain.
5.Turn Power switch from ‘Off’ to ‘On’. Unit is
ready to play when LED is on. Note: if the
power indicator LED fails to light, turn the
Power switch to ‘Off’ and check the
appropriate fuse for possible failure. Extra
fuses for AC power are included with the
unit. If green light is blinking after turn on, a
low line voltage condition exists–turn off
amplifier and check line voltage.
6.Your amplifier should now operate
satisfactorily. It may be played
immediately, although best sonic
performance will in most cases not be
achieved for an hour or so (see
INSTALLATION for further details.)
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Start-Up Following ‘Protect’
Shutdown:
The DS450 amplifier uses a sophisticated,
non-fused sensing circuit to protect the
amplifier from DC at the input, from thermal
overload, and from shorting conditions at
the output (e.g. defective speaker leads,
etc.). This circuit also helps prevent damage
to your loudspeakers.
When the amplifier senses a fault condition
in either channel from excessive DC or
excessive output current, it will
automatically shut off left or right outputs
from the amplifier. Amplifier will
automatically return to normal operation
when fault is removed.
If the amplifier fails to resume normal
operation after removal of a fault condition,
contact your authorized dealer for further
assistance.
Servicing
Because of its careful design and exacting
standards of manufacture, your DS450
amplifier should normally require only
minimal service to maintain its high level of
performance.
CAUTION: The DS450 amplifier contains
sufficient levels of voltage and current to be
lethal. Do not tamper with a component or
part inside the unit. Even with the power
turned off, a charge remains in the energy
storage capacitors for some time. Refer any
needed service to your authorized Audio
Research dealer or other qualified
technician.
Additional questions regarding the
operation, maintenance or servicing of your
amplifier may be referred to the Customer
Service Department of Audio Research
Corporation at 763.577.9700 (CST). When
ordering a service manual from Audio
Research or an authorized dealer, be sure to
identify the serial number on your amplifier.
Cleaning
To maintain the new appearance of this
unit, occasionally wipe the front panel and
top cover with a soft, damp (not wet) cloth
to remove dust. A mild, non-alkaline soap
solution or dilute isopropyl alcohol may be
used to remove fingerprints or similar
smudges. Cleaners containing abrasives
should not be used as they will damage the
anodized finish of the front panel. A small,
soft paintbrush is effective in removing dust
from bevels, the recessed nameplate and
other features of the front panel.
Disposal and Recycling
Guidelines
To dispose of this electronic product, do not
place in landfill.
In accordance with the European Union
Waste Electrical and Electronic Equipment
(WEEE) directive effective August 2005, this
product may contain regulated materials
which upon disposal require special reuse
and recycling processing.
Please contact your dealer or importing
distributor for instructions on proper disposal
of this product in your country. Or, contact
Audio Research Corporation (763.577.9700)
for the name of your importing distributor
and how to contact them.
Packing and shipping materials may be
disposed of in a normal manner.
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Limited Warranty
Audio Research Corporation products are
covered by a 3-Year Limited Warranty, or a
90-Day Limited Warranty (vacuum tubes).
This Limited Warranty initiates from the date
of purchase, and is limited to the original
purchaser, or in the case of demonstration
equipment, limited to the balance of
warranty remaining after original shipment
to the retailer or importer.
In the United States, the specific terms,
conditions and remedies for fulfillment of this
Limited Warranty are listed on the warranty
card accompanying the product in its
shipping carton, or may be obtained from
the authorized retailer or from the Audio
Research Customer Service
Department. Outside the United States, the
authorized importing retailer or distributor
has accepted the responsibility for warranty
of Audio Research products sold by them.
The specific terms and remedies for
fulfillment of the Limited Warranty may vary
from country to country.
Warranty service should normally be
obtained from the importing retailer or
distributor from whom the product was
purchased.
In the unlikely event that technical service
beyond the ability of the importer is
required, Audio Research will fulfill the terms
and conditions of the Limited Warranty.
Such product must be returned at the
purchaser's expense to the Audio Research
factory, along with a photocopy of the
dated purchase receipt for the product, a
written description of the problem(s)
encountered, and any information
necessary for return shipment. The cost of
return shipment is the responsibility of the
purchaser.
Specifications
POWER OUTPUT: 450 watts into 8 ohms (550 watts
per channel into 4 ohms), both channels
driven, 1% THD. (700 watts into 4 ohms, one
channel driven)
POWER BANDWIDTH: (-3dB Points) 5Hz to 45 kHz
into 8 ohms.
FREQUENCY RESPONSE: (-3dB points at 1W) 5Hz to
45 kHz
INPUT SENSITIVITY: 2.9V RMS for rated output
(26dB Gain) single-ended or balanced.
INPUT IMPEDANCE: 150K ohms single-ended, 300K
ohms balanced differential.
OUPUT POLARITY: Non-inverting from single-ended
inputs. Balanced pin 2+ (IEC-268).
OUTPUT REGULATION: 0.02dB 8 ohm load to open
circuit (Damping factor 440).
OUTPUT CURRENT: 35 amps peak at protective
shutdown.
SLEW RATE: 5 volts/microsecond. (20% maximum
duty cycle).
RISE TIME: 8.0 microseconds.
HUM & NOISE: 300 microvolts RMS (105dB below
rated output IHF A-weighted).
POWER SUPPLY CAPACITANCE: 217,000 uF total.
POWER REQUIREMENTS: 100-125VAC 60Hz (200-
250VAC 50Hz) 950 watts at rated output
(400WPC 8 ohms), 1300 watts at 550WPC 4
ohms, 1300 watts maximum, 55 watts idle.
DIMENSIONS: 19" (48 cm) W (standard rack
panel) x 7" (17.8 cm) H x 18.4" (46.7 cm) D (front
panel back). Handles extend 1.5" (3.8 cm)
forward of the 3/8" thick front panel. Output
connectors extend 1.5" (3.8 cm) behind rear
panel.
WEIGHT: 55.8 lbs. (25.4 kg) Net; 71 lbs. (32.3 kg)
Shipping.
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3900 Annapolis Lane North
Plymouth, MN 55447
763.577.9700
www.audioresearch.com
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