Audio Research SE Series User manual

Reference 150 SE
H I G H D E F I N I T I O N ®

Thank You.
Thank you for choosing the
Reference150SEtobeapartofyour
high performance music listening
system. Since 1970, Audio Research
has been creating some of the
world’s nest audio equipment.
Each piece is handcrafted in
Minnesota, and has been designed
to provide many years of listening
enjoyment.
We understand you are eager to
begin listening; however, please
take a few minutes to read through
this guide for useful information
concerning the operation of your
new amplier. Once installed,
please allow an appropriate break-
in period to fully appreciate the
benets this amplier will provide
to your system.
After reading the user guide, if
you have any further questions
regarding your amplier, contact
your dealer or Audio Research
customer service - they will be
happy to help you make the most
of your new component.
Happy Listening!

4
Warnings.......................................................5
Installation...................................................6
Before Operating the Reference 150 SE ..........6
In Your System...............................................7
A Note about Vacuum Tubes........................7
Connections .................................................8
Back Panel Controls and Connections ..........8
Input Connectors ..........................................9
Output Connectors.......................................9
Matching........................................................9
Remote Turn-on ..........................................10
A.C. Power Connection................................ 11
Operation ....................................................12
Front Panel ...................................................12
Start-Up........................................................13
Shut-Down ...................................................13
Break-in.........................................................13
Output Tube Bias Adjust............................. 14
Hour Counter .............................................. 14
Maintenance .............................................. 15
Vacuum Tubes ............................................. 15
Servicing ...................................................... 15
Cleaning....................................................... 15
Disposal and Recycling Guidelines............. 15
Fuse Values and Locations.......................... 16
Warranty......................................................17
Specication .............................................. 18
Contents
Cooling Fan Speed Adjustment.................. 14

5
To prevent re, or shock hazard, do not
expose your Reference 150 SE to rain or
moisture.
Do not place objects containing water on
top of this unit.
This unit contains voltages which can cause
serious injury or death. Do not operate with
covers removed. Refer servicing to your
authorized Audio Research dealer or other
qualied personnel.
The detachable power cord on your
Reference 150 SE is equipped with a heavy
gauge, 3-conductor cable and a standard
three-prong grounding plug. For absolute
protection, do not defeat the ground power
plug. This provides power line grounding
of the Reference 150 SE chassis to provide
absolute protection from electrical shock.
Theappliancecoupler(a.c.power connector)
at the rear of this unit must be accessible for
emergency power disconnect.
If the unit is to be operated in an enclosure
such as an equipment rack, make certain
that adequate airow above and to each
side of the unit is provided, and ensure that
the ventilation fans on the back panel are
not obstructed.
For continued protection against re hazard,
replace the fuse only with the same type and
rating as specied at the fuse holder.
This unit is RoHS compliant.
A note about packaging...
Save all packaging in a dry place away from
re hazard. Your Reference 150 SE amplier is
a precision electronic instrument and should
be properly cartoned any time shipment is
made. You may not have occasion to return
your unit to the factory for service, but if that
should prove necessary, or other occasion
requiring shipment occurs, the original
packaging will protect your Reference 150 SE
from unnecessary damage or delay.
Warnings

6
Before operating the Reference 150 SE
Your Reference 150 SE amplier is shipped
with the vacuum tubes packed in foam
blocks.Thesemustbeunpackedandinstalled
before you attempt to operate the amplier.
Included are two matched quads of KT150
output tubes, and four 6H30 dual triodes
used in the input stage. Proceed according
to the following instructions.
Remove all screws fastening the top cover.
Carefully remove each vacuum tube from its
protective foam and match its location ‘V’
number (written on the base of the tube) to
the ‘V’ number printed next to each socket.
Firmly seat each tube in its matching socket,
taking care to‘key’ the tubepins to the socket
holes. Retain the foam blocks with other
packing materials for possible future use.
Refasten top cover on amplier.
V8
V6
V12
V10
V4
V2
V7
V5
V11
V9
V3
V1
hour counter
hour counter reset
Installation

7
In your system
To insure normal component life and safe
operation this unit must be operated only
in an upright position. Adequate airow and
proper cooling can occur only if there is no
restriction above and behind the unit and on
either side.
The special non-marring elastomer feet
provide adequate spacing and stability
only on a smooth, hard surface, and also
assist to isolate the amplier from spurious
vibrations. For upright stability and best
performance, never operate the unit while it
is sitting on a soft surface such as a thick rug
or carpet.
Due to its weight, this amplier must be
supported on a surface specically rated for
such a load. Check with the manufacturer of
your support system to be sure it is rated to
handle this weight.
If the unit is to be operated in an enclosure
such as an equipment rack, make certain
that adequate airow above and to each
side of the unit is provided.
The ‘ambient’ operating temperature should
never exceed 86° F or 30° C. Improper
installationwillcauseprematuretubefailure
and will aect your warranty, as well as the
service life of the unit.
It is normal for a vacuum tube power
amplier to run quite warm, and if used
for prolonged periods, hot to the touch. All
components within are, however, operated
at safe, conservative levels and will not be
improperly aected thereby, providing the
requirements outlined above are adhered to.
A Note about Vacuum Tubes
The vacuum tubes in your Reference 150 SE
have been burned in, tested and electrically
matched to provide the best performance
and reliability of your amplier. That said,
vacuum tubes must be replaced from time
to time. The KT150 output tubes in the
Reference 150 SE should have an expected
life of approximately 3,000 hours, while
the smaller 6H30 tubes should have a life
expectancy of approximately 4,000 hours.
Theselifeexpectanciesareonlyapproximate.
Installation

8
CAUTION
FOR CONTINUED PROTECTION AGAINST
FIRE HAZARD REPLACE FUSE ONLY
WITH SAME TYPE AND RATING
WARNING
RISK OF HAZARDOUS ENERGY!
MAKE PROPER SPEAKER CONNECTIONS
SEE OWNERS MANUAL
VOLTS SERIAL
WARNING
TO PREVENT FIRE AND SHOCK HAZARD, DO NOT
EXPOSE THIS DEVICE TO RAIN OR MOISTURE.
UNIT MUST BE OPERATED IN A HORIZONTAL POSITION.
-DO NOT OPERATE WITH COVERS REMOVED-
UNIT CONTAINS VOLTAGES WHICH MAY BE HAZARDOUS.
WARNING
RISK OF HAZARDOUS ENERGY!
MAKE PROPER SPEAKER CONNECTIONS
SEE OWNERS MANUAL
REFERENCE 150
STEREO AMPLIFIER
PLYMOUTH, MINNESOTA
MADE IN U.S.A.
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION !
IN OUT
+12V REMOTE
TURN ON
LEFT INPUTRIGHT INPUT
0 4 8 16
0 4 8 16
900W MAX 50/60 HZ ~7A FUSE
SLO-BLO
T4A (230V)
Left and Right XLR inputs
12V remote trigger
Speaker connections
Fuse holder
A.C. Mains connector
Back Panel Controls and Connections
Connections

9
Input Connectors
The Reference 150 SE uses a fully balanced
circuit topology and has a pair of balanced
XLR input connectors on the rear panel. It
therefore requires a balanced preamplier
output, as provided by most Audio Research
preampliers. Connect your preamplier’s
output to the Reference 150 SE before
turning on the amplier.
Output Connectors
Heavy-duty output terminals are provided
on the rear panel for 4, 8, or 16-ohm speaker
impedance loads. Using high-quality speaker
cables, securely fasten the (-) speaker lead to
theappropriate(black)terminal,thenthe(+)
lead to the matching (red) terminal. Follow
your speaker manufacturer’s impedance
specication.
The Reference 150 SE puts out the same
amount of power whether the 4, 8, or 16-
ohm terminals are used.
Matching
It is important to use as close as possible
an impedance match between the amplier
and speaker for optimum transfer of
power to the speaker with minimum
distortion. In the case of speaker systems
with signicant variations in impedance
throughout the frequency spectrum, such
as most electrostatic types, determine the
best impedance match empirically for best
overall sonic results.
Connect the Reference 150 SE input to the
preamplier or electronic crossover, using
only the highest grade of audio interconnect
cables. To avoid sonic degradation use the
shortest practical length of cables.
Important
Use the best available speaker wires
and interconnects. Audio Research
cannot emphasize this enough. As better
components and systems are developed,
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,
or ‘absolute’ polarity (i.e., non-inverted).
Connect the black or ‘–‘ speaker terminal to
the wire that connects to the ‘0’ terminal on
the Reference 150 SE. Connect the red or ‘+’
speakerterminaltothewirethatconnects to
the 4, 8, or 16-ohm terminal on the Reference
150 SE and tighten the speaker terminals
securely to ensure best sonic results.
Connections

10
Remote Turn-on
The Reference 150 SE has a built-in 12V DC
remote turn-on/o 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
Reference 150 SE.
The +12V IN jack should be connected to
the +12V DC output of the master control
system, using a continuous +12V DC signal at
12mAper Reference150SEforthe durationof
amplier on-time. Do not use a momentary
or data pulse control signal.
The +12V DC remote jacks have polarity
protection, so they will not operate if a -12V
DC signal is accidentally connected, or if the
control wires are reversed.
When the 12V DC remote turn-on/o circuit
is used, the power switch on the front panel
should be turned o.
Connections

11
A.C. Power Connection
It is important that the Reference 150 SE
be connected via its supplied 20 amp IEC
12-gauge power cord to a secure, dedicated
A.C. power receptacle. Never connect to
convenience power receptacles on other
equipment. Only use the power switch on
the front of the Reference 150 SE for On/O
control of the amplier, or the 12V start-up
trigger for remote installations.
The AC power source for the Reference 150
SE amplier should be capable of supplying
10 amperes for 100 or 120 volt units, or 5
amperes for 220 or 240 volt units.
For the very best performance on 100 or 120
volt circuits, the Reference 150 SE should
be connected to its own AC power circuit
branch, protected by a 15 amp breaker. The
preamplier and other audio equipment
should be connected to a dierent power
circuit and breaker.
The Reference 150 SE should be turned
on after the other components of your
system. If the Reference 150 SE is turned on
before other components, the amplier will
amplify any extraneous turn-on noises those
components might generate, which could
potentially damage the loudspeakers. Good
operating practice dictates that the amplier
should be turned on last, and turned o rst
in an audio system.
The Reference 150 SE uses a grounding
system that does not require a ground-
lifter adapter plug on the A.C. power cord
to minimize hum. The power cord supplied
with the Reference 150 SE has a standard
grounding plug to provide maximum safety
when properly connected to a grounded
wall receptacle. If there is any question
regarding proper grounding procedures in
your installation, seek help from a qualied
technician. Caution should be taken before
using custom after-market power cords:
they must be at least 12-gauge and have a
standard grounding plug properly installed.
These power cords are to be used with
caution, at the sole risk of the owner.
If electronic crossovers or other AC powered
equipment is used with the Reference
150 SE 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 preamplier, through
its grounded power cord. Other equipment
in the system should have some form of
isolation to prevent ground loops and
associated hum.
Connections

12
VACUUM TUBE
POWER AMPLIFIER REFERENCE 150
HIGH DEFINITION R
Main Power Switch
Front Panel
Operation

13
Start-Up
•Secure interconnects between the amplier
and your preamplier; attach speaker leads
to the appropriate output terminals.
•Attach supplied power cord to rear IEC
inlet of amplier, and plug other end into
grounded A.C. power receptacle.
•Turn on preamp and all other components;
mute preamp output.
•Press Reference 150 SE front panel control
switch. Green power LED will light.
•Unmute preamplier output, initiate
source component signal, and adjust gain
as appropriate.
Shut-Down
•Mute preamplier output.
•Switch Reference 150 SE front panel control
switch to o.
•Turn o preamplier and then the
associated input source components.
Break-in
All quality stereo equipment benets from a
break-in period; during this time, the various
components, wiring and solder connections
change as electrical signals pass through
them.Whileyour Reference150 SEwillsound
fantastic out of the box, it will only improve
with continued use.
Important!
After the Reference 150 SE is turned o,
wait at least ve minutes before turning
it on again. This allows the large bank of
storage capacitors to drain energy. Not
allowing enough time for this process can
result in blown fuses or other damage to
your amplier.
Operation

14
Output Tube Bias Adjustment
Asshippedfromthefactory,the output‘bias’
adjustments are set for a nominal 65mA per
KT150 tube. Under these idle conditions the
tubes are each dissipating approximately 27
watts of their 75 watt rating. This point of
operation provides ‘enriched’ Class AB1, and
will satisfy the most critical listener.
For best results, operate and adjust the
Reference 150 SE at 120V AC. Adjustment
must be made under zero-signal conditions
after at least 15-20 minutes of uninterrupted
stabilization time.
A digital voltmeter capable of accurate
measurements with 0.1 mVDC resolution
is preferred for accurate adjustment (must
have 3 ½ digit display). Use the plastic
alignment tool provided to make the
adjustment. The measurement points are
yellow and black banana test jacks next to
each output tube. Adjust the ‘bias’ for a
voltage reading of 65mVDC (.065Volt DC) at
the blue bias pot for one of each output tube
pair as follows, noting the voltage setting
of the larger V number tube in each pair is
slaved to the adjustment setting of its lower
V number companion tube: for example,
adjust V5 for 65mVDC and measure its
companion tube V7 to verify a reading of 57
to 73mVDC. Repeat procedure by adjusting
andmeasuringV9to read 65mVDCandverify
V11 reads 57-73mVDC; adjust and measure
V6 to read 65mVDC and verify V8 reads 57-
73mVDC, and nally adjust and measure V10
to read 65mVDC andverify that V12 reads 57-
73 mVDC.
Hour Counter
An LCD hour counter of elapsed tube
operating time can be viewed through the
top cover near the front, mounted on the
right main circuit board (see illustration
page 6). This displays accumulated hours
of vacuum tube service life. If the amplier
is unplugged from A.C. supply, the total
accumulated hours are retained. Adjacent
to the hour counter is the hour counter reset
button; after replacing vacuum tubes, press
this button to reset the hour counter back
to zero. Note that once the hour counter has
been reset, it is no longer possible to
recall the previous hour count.
Cooling Fan Speed Adjustment
The two D.C. cooling fans located at the
rear of the Reference 150 are adjustable in
speed. Locate the red colored dip switch
under the top cover at the top near the
center of the back panel. For highest fan
speed move both white tabs on the red dip
switch to the upward position; for medium
fan speed move either one of the tabs to
the downward position, and for low fan
speed move both tabs to the downward
position. For maximum cooling and
extended tube life, use the highest fan
speed possible. Be sure to first turn off and
unplug the Reference 150SE from its power
receptacle before unscrewing the top cover
to access the switch. Refasten the top cover
before resuming operation. Do not operate
the Reference 150SE with fans disconnected
or if one or both fans should stop running.
Operation

15
Maintenance
Vacuum Tubes
It is recommended that you replace the
vacuum tubes of your Reference 150 SE in
sets. All of the tubes in your amplier have
been matched to have similar operating
characteristics, to provide the best sound
quality and reliability. In the event you need
to replace a single output tube, please refer
to the numbers written on the silver base
at the bottom of the vacuum tube when
ordering a new tube.
Servicing
Because of its careful design and exacting
standards of manufacture, your Reference
150 SE amplier should normally require only
minimal service to maintain its high level of
performance.
Caution
Your Reference 150 SE amplier contains
sucient levels of voltage and current to
be lethal. Do not tamper with a component
or part inside the unit. Even with the power
turned o, a charge remains in the energy
storage capacitors for some time. Refer
any needed service to your authorized
Audio Research dealer or other qualied
technician. Additional questions regarding
the operation, maintenance or servicing of
your amplier, please contact the Customer
Support Department of Audio Research
Corporation at [email protected]
or call 763-577-9700. You may also initiate
a service request by visiting the Audio
Research website (www.audioresearch.com)
and selecting ‘Service Repair’ at the top right
of the home page.
Cleaning
To maintain the new appearance of this
amplier, occasionally wipe the front panel
and top cover with a soft, damp (not wet)
cloth to remove dust. A mild, non-alkaline
soap solution may be used to remove
ngerprints or similar smudges. Cleaners
containing abrasives should not be used
as they will damage the anodized nish of
the front panel. A small, soft paintbrush is
eective 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 landll. In accordance with
the European Union Waste Electrical and
Electronic Equipment (WEEE) directive
eective August 2005, this product
may contain regulated materials which
upon disposal require special reuse and
recycling processing.
Please contact your dealer or importing
distributorforinstructionsonproperdisposal
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.

16
Fuse Values and Locations
The Reference 150 SE has three fuses; one
external mains fuse, and two internal fuses.
Please refer to the illustration below to
determine fuse locations. Refer to the table
at right for values. When replacing fuses, use
the exact values indicated. Audio Research
is not responsible for damage caused by
improper fuse values or aftermarket fuses.
Mains Fuse (indicated in BLUE)
100-125 V units: Bussman MDQ7 slo-blo
220-250 V units: T4A slo-blo
High Voltage Fuse (indicated in RED)
100-125 V units: Bussman MDQ4 slo-blo
220-250 V units: T3.15A slo-blo
High Voltage Fuse
Mains Fuse
When changing an internal fuse (or any time the cover of the unit
is removed), make certain the main power is disconnected from the
A.C. line. Be very careful working around circuit boards as there are
dangerous voltages internally. If you are not comfortable opening your
amplier, please refer to a qualied service technician.
Maintenance

17
Audio Research Corporation products are
covered by a 3-Year Limited Warranty or a
90-Day Limited Warranty (vacuum tubes).
This LimitedWarranty 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 specic terms,
conditions and remedies for fulllment
of this Limited Warranty are listed on the
warranty card accompanying the product
in its shipping carton. The warranty terms
are also available on the internet at www.
audioresearch.com/en-us/company/
warranty-statement. Outside the United
States, the authorized importing retailer or
distributor has accepted the responsibility
for warranty of Audio Research products
sold by them.
The specic terms and remedies for
fulllment 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 fulll 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.
Warranty

18
Power Output:
150 watts per channel continuous
from20Hz to 20kHz. 1kHz total
harmonic distortion typically 0.6% at
150 watts, below 0.03% at 1 watt.
Approximate actual power available
at ‘clipping’ 160 watts (1kHz). (Note
that actual power output is dependent
upon both line voltage and ‘condition’
i. e.: if power line has high distortion,
maximum power will be aected
adversely, although from a listening
standpoint this is not very critical)
Power Bandwidth: (-3dB points)
5Hz to 80kHz
Frequency Response: (-3dB points
at 1 watt) 0.5Hz to 120 kHz
Input Sensitivity: 2.0V RMS BAL for rated
output. (24 dB Bal gain into 8 ohms)
Input Impedance: 300K ohms Balanced
Output Polarity: Non-inverting.
Balanced input pin 2+ (IEC-268)
Output Taps: 16 ohms, 8 ohms, 4 ohms
Output Regulation: Approximately
0.6dB 16 ohm load to open circuit
(Damping factor approximately 14)
Overall Negative Feedback: 14dB
Slew Rate: 13 volts/microsecond
Rise Time: 2.0 microseconds
Hum & Noise: Less than 0.1mV
RMS – 114dB below rated output
(IHF weighted, input shorted)
Power Supply Energy Storage:
Approximately 1040 joules.
Power Requirements: 105-
125VAC 60Hz (210-
250VAC 50Hz) 730 watts at rated output,
900 watts maximum, 420 watts idle
Tubes Required: 4 – Matched pair KT150
– Power Output; 4 – 6H30 Driver
Dimensions:
width: 19” (48.3 cm)
height: 8.75” (22.2 cm)
depth: 19.5” (49.5 cm)
Handles extend 1.5” (3.8 cm) forward
Weight:
75 lbs. (34.2 kg) Net
90 lbs. (41 kg) Shipping
Specications

19

Specications subject to change without notice.
©2015 Audio Research Corporation. Reproduction of this document in part or whole is expressly forbidden without written
consent from Audio Research Corporation.
H I G H D E F I N I T I O N ®
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Plymouth, MN 55447
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