Audio Research REF 160M User Manual

VACUUM TUBE MONOBLOCK AMPLIFIER

REF 160M

User’s Manual

Customers Come First

Quality Every Day

Advancing Our Legacy

Commitment to Excellence

Thank you for choosing the
Reference 160M to be a part of your
high performance music listening
system. After nearly 50 years, our
focus remains the advancement
of the state-of-the-art in music
reproduction. Every component
is meticulously hand-crafted and
personally auditioned before it
leaves our factory. Our attention to
detail, customer service, and product
support create unprecedented value.
An Audio Research component
is more than a purchase, it’s
an investment.

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 further questions regarding

your amplier, contact your dealer or

Audio Research customer service—

Thank You.

they will be happy to help you make
the most of your new component.

Happy Listening!

Safety Instructions

Important Safety Instructions

The lightning ash 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

sucient magnitude to constitute a risk of electric shock to persons.

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

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water

6. Clean only with dry cloth.

7. Do not block any ventilation openings. Install in accordance

with the manufacturer’s instructions.

8. Do not install near any heat sources such as radiators, heat registers,

stoves, or other apparatus (including ampliers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding-type plug. A

polarized plug has two blades with one wider than 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 t into your

outlet, consult an electrician for replacement of the obsolete outlet.

10. Protect the power cord from being walked on or pinched particularly at plugs,

convenience receptacles and the point where they exit from the apparatus.

11. Only use attachments/accessories specied by the manufacturer

2

Safety Instructions

12. Use only with the cart, stand, tripod, bracket, or table specied 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

13. Unplug this apparatus during lightning storms or when unused for long periods of time.

14. Refer all servicing to qualied 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.

15. WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO

NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE

16. DO NOT EXPOSE THIS APPARATUS TO DRIPPING OR SPLASHING AND THAT NO

OBJECTS FILLED WITH LIQUIDS, SUCH AS VASES, SHOULD NOT BE PLACED ON
THE APPARATUS and NE PAS EXPOSER CET APPAREIL À DES ÉCLABOUSSURES
OU GOUTTELETTES D’UN LIQUIDE. AUCUN OBJET REMPLIE DE LIQUIDE
COMME PAR EXEMPLE UN VASE NE DOIT ETRE PLACE SUR L’APPAREIL.

17. TO COMPLETELY DISCONNECT THIS APPARATUS FROM THE AC MAINS,

DISCONNECT THE POWER SUPPLY CORD PLUG FROM THE AC RECEPTACLE. POUR
DECONNECTER COMPLETEMENT L’APPAREIL DU RESEAU D’ALIMENTATION,
DECONNECTER LE CORDON D’ALIMENTATION DE LA PRISE MURALE.

18. THE MAINS PLUG OF THE POWER SUPPLY CORD SHALL REMAIN READILY ACCESSIBLE.

LA PRISE DU RESEAU D’ALIMENTATION DOIT DEMEURER AISEMENT ACCESSIBLE.w

3

Contents

Safety Instructions ...................................... 2

Warnings.......................................................5

A note about packaging................................5

Installation ...................................................6

Top view ......................................................... 6

Before operating the reference 160M ..........6

In your system ............................................... 7

A note about vacuum tubes ......................... 7

Life Expectancy .............................................7

Connections .................................................8

Back Panel Connections................................8

Input Connectors ..........................................8

Output Connectors .......................................8

Matching........................................................9

Maintenance .............................................. 15

Vacuum Tubes ............................................. 15

Servicing ...................................................... 15

Caution ........................................................ 15

Cleaning ....................................................... 15

Disposal and Recycling Guidelines ............. 15

Warranty..................................................... 16

Specication ...............................................17

Loudspeaker Cable Distance ........................9

Remote Turn-on .......................................... 10

RS-232 Control ............................................ 10

A.C. Power Connection ............................... 10

Operation .................................................... 11

Front Panel Controls and Displays ..............11

Start-Up ........................................................12

Shut-Down ...................................................12

Front Panel Button Functions .....................13

Back Panel Toggle Switch Functions ...........13

Auto Shut O ...............................................13

Auto Bias ..................................................... 14

Hour Counter .............................................. 14

Break-in ........................................................ 14

4

Warnings

To prevent re, or shock hazard, do not expose

your Reference 160M 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
160M is equipped with a heavy gauge,
3-conductor cable and a standard three­prong grounding plug in North America.
For absolute protection, do not defeat the
ground power plug. This provides power line
grounding of the Reference 160M chassis to
provide absolute protection from electrical
shock.

The appliance coupler (a.c. power connector)
at the rear of this unit must be accessible for
emergency power disconnect.

A note about packaging...

Save all packaging in a dry place away from

re hazard. Your Reference 160M 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 160M
from unnecessary damage or delay.

Important!

The AC Power Supply Cord must be

disconnected from the amplier before

replacement or installation of vacuum tubes.
See next page (6) Before operating the
Reference 160 M.

Important!

Vacuum tube installation and replacement

should be performed by a qualied technician.

For continued protection against re hazard,

replace the fuse only with the same type and

rating as specied at the fuse holder.

The power button on the front of this unit,

when o, does not disconnect all power

from this unit. This unit is in sleep mode
when not on.

This unit is RoHS compliant.

5

Installation

Top View

Vacuum Tubes

6H30

KT150

Vacuum Tubes

KT150
Vacuum Tubes

Before operating the Reference 160M

Your Reference 160M amplier is shipped

with the vacuum tubes packed in foam
blocks. These must be unpacked and
installed before you attempt to operate

the amplier. Included are a matched quad

of KT150 output tubes and (2) 6H30 dual

triode driver tubes. Proceed according to the
following instructions.

Remove only the screws fastening the top
cover. Do not remove any other screws.
Remove packing foam under top cover
and store with other packing materials.

6

Installation

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 tube pins to
the socket holes. Retain the foam blocks
with other packing materials for possible
future use.

Refasten top cover on amplier. Connect the

fan power plug to its socket at the rear of

the amplier top plate.

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 are no
restrictions above and behind the unit and

on either side. Be sure that airow to the 12V

D. C. cooling fan located on the rear panel is
not blocked.

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, to each side,

and to the rear of the unit is provided.

In any installation, there should be a
minimum of 8 inches of clearance above the

top of the amplier.

The ‘ambient’ operating temperature should
never exceed 86° F (30° C). Improper
installation will cause premature tube failure

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
Life Expectancy

The vacuum tubes in your Reference 160M
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 160M 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.
These life expectancies are only approximate.

7

Connections

Back Panel Connections

Defeat/Auto Shut O

Switch

Fan Speed

Switch

Balance/Single Ended

Switch

MINNEAPOLIS, MINNESOTA

500 WATTS MAX 50/60Hz~

5A SLO-BLO
T3.15 (230V)

CAUTION

FOR PROTECTION

AGAINST FIRE HAZARD
REPLACE ONLY WITH
SAME RATING FUSES

REFERENCE 160M

MONAURAL AMPLIFIER

HIGH

DEFEAT

LOW

AUTO

FAN SPEED

SHUT OFF

HOURS

WARNING

TO PREVENT FIRE AND SHOCK HAZARD
DO NOT EXPOSE THIS DEVICE TO RAIN

OR MOISTURE.

UNIT MUST BE OPERATED IN HORIZONTAL POSITION.

-DO NOT OPERATE WITH COVERS REMOVED-

UNIT CONTAINS VOLTAGES WHICH MAY BE HAZARDOUS

BALANCED

SINGLE
ENDED

BALANCED

Inputs

INPUTS

SINGLE
ENDED

RS-232

Connector

+12V

REMOTE TURN ON

RS-232 IN OUT

4 Ω0 Ω 8 Ω 16 Ω

WARNING

RISK OF HAZARDOUS ENERGY! MAKE PROPER SPEAKER CONNECTION

SEE OWNER MANUAL

12V
Trigger In/Out

A.C. Mains connector

Line Fuse

Reset Button/
Hours Meter

Speaker Terminals

Input Connectors

The Reference 160M uses a fully balanced circuit topology and has a balanced XLR input
connector and a single-ended RCA input connector on the rear panel. The rear panel switch
must be in the appropriate labeled position for either balanced or single-ended use. Connect

your preamplier’s output to the REF 160M input connector before turning on the amplier.

Do not connect the balanced XLR input connector and single-ended RCA input connector at
the same time –connect one or the other in the same way for both channels.

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 the appropriate (black) terminal, then the (+) lead to the matching (red) terminal. 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). Do not over tighten the
output terminal connectors on the amp (use a hex driver and tighten snugly -do not over

tighten). Follow your speaker manufacturer’s impedance specication. The Reference 160M

puts out the same amount of power whether the 4, 8, or 16-ohm terminals are used.

8

Connections

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 160M 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.

When connecting Loudspeakers to the REF 160M it is very important to use cables of adequate

size, so there is little to no power loss in the cables. The size is specied in Gauge Numbers or

AWG (American WireGauge). The smaller the Gauge number, the larger the wire size:

Loudspeaker Cable Distance vs. Wire Gauge Guide

25 feet

50 feet

100 feet

Loudspeaker

(7.62 meters)

(15.24 meters)

(30.48 meters)

Impedance

or less

or less

or less

4 Ohms 14AWG 12AWG 10AWG

8 Ohms 16AWG 14AWG 12AWG

16 Ohms 18AWG 16AWG 14AWG

Prepare the Loudspeaker Hookup Cable for attachment to the REF 160M Power Amplier Circuitry.
Bare wire cable ends: carefully remove sucient insulation from the cable ends, refer to gures

A, B & C. If the cable is stranded, carefully twist the strands together as tightly as possible.

Notes:

1. If desired, the twisted ends can be tinned
with solder to keep the strands together.

2. The prepared bare wire cable ends may be
inserted into spade lug connectors.

3. Banana plugs are for in the United States
and Canada only.

9

Connections

Remote Turn-on

The Reference 160M 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 160M.
The tip of the mini plug is +12V and the sleeve
is ground.

The +12V IN jack should be connected to
the +12V DC output of the master control
system, using a continuous +12V DC signal at
12mA per Reference 160M for the duration of

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.

RS-232 Control

The REF 160M has an RS-232 connector on

the back panel, in the event the amplier

is incorporated into an automated or two­way remote communication system. Please
see your dealer or contact customer service

at Audio Research to acquire specic codes

relative to the RS-232 control.

A.C. Power Connection

It is important that the Reference 160M
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 160M for On/ O control of
the amplier, or the 12V start-up trigger or

RS-232 for remote installations.

The AC power source for the Reference 160M

amplier should be capable of supplying

15 amperes for 100 or 120 volt units, or 10
amperes for 220 or 240 volt units.

For the very best performance on 100 or
120 volt circuits, the Reference 160M should
be connected to its own AC power circuit
branch, protected by a 15 (or 20) amp breaker.

The preamplier and other audio equipment
should be connected to a dierent power

circuit and breaker.

The Reference 160M 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
160M 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 after­market 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 160M it may be necessary to
use ‘ground lifter’ adapters on the power

10

Operation

Front Panel Controls and Displays

Power Meter

Tube Status Tube Status

Power On/O

Meter Light

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.

Ultralinear/
Triode mode

Tube Monitor

Other equipment in the system should have
some form of isolation to prevent ground
loops and associated hum.

11

Operation

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 160M front panel power

switch. Green power LED will ash dim-to-

bright for approximately 2 minutes during

the auto mute cycle to allow the amplier

to stabilize voltage before becoming
active. The LED will stay on brightly, once

the amplier has stabilized.

• Note: the Reference 160M should be turned

on after the other components of your
system. If the Reference 160M is turned on

before other components, the amplier

will amplify any extraneous turn-on noises
those components might generate, which
could potentially damage loudspeakers.

Good practice dictates that the amplier
should be turned on last and turned o
rst in an audio system.

Shut-Down

• Mute preamplier output.

• Turn o Reference 160M via front panel
power switch. (or 12V trigger or RS-232)

• Turn o preamplier and then the
associated input source components.

• The control circuitry is programmed
to prevent turning the unit on within
approximately 2 minutes after shut-down.

Important!

After the Reference 160M is tuned 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.

• Unmute preamplier output, initiate
source component signal, and adjust gain
as appropriate.

12

Operation

Front Panel Button Functions
Power

Turns power of REF 160M on or o.

Meter Light

Adjusts meter light LED display brightness
to one of four levels of brightness including

“o  ”.

Tube Monitor

Allows checking the operation of each of
the four KT 150 output tubes (V1-V4). The
LED associated with each output tube
will illuminate when operating properly.
See Auto Bias section under Operation for
further explanation of its operation.

Ultra-Linear/Triode

Allows selecting ultra-linear (approximately 150
watts/ch.) operation –indicated by green color
of LED above this function button, or triode
(approximately 75 watts/ch.) operation –
indicated by blue white color of LED above
this function button.

Balanced/Single Ended

Select balanced switch position for balanced
input connection operation or single-ended
switch position for single-ended input
connection operation. Do not connect BAL
and SE cables simultaneously. (See Input
Connectors paragraph under Connections
section for further information.)

Auto Shut O

The REF160M is equipped with an auto

shut-o feature, designed to turn the
amplier o after two hours of no signal
being present at the output of the amplier.

In the event that quiet music is listened
to at very low volumes, there may not be

adequate signal for the auto shut o circuit,
resulting in the amplier turning itself o. If

this is the case, please disengage the auto

shut o feature. The auto shut o feature

control switch is located on the back panel
of the REF 160M. Toggling the switch allows

you to turn the feature on or o.

Back Panel Toggle Switch Functions

Auto Shut O/Defeat

Allows selecting auto shut-o feature or
turning o this feature (see separate Auto
Shut O paragraph under this Operation

section for a more detailed description of
this function).

High/Low Fan Speed

Allows adjusting fan speed of top cover/fan
assembly to either low or high-speed setting.

Note: The auto shut o feature is not in
the signal path of the amplier and has no
deleterious sonic eect on music playback.

13

Operation

Auto Bias

The REF160M incorporates a highly
sophisticated auto-bias circuit. There are no
user-adjustable bias controls. There should
never be a need to check or adjust the
auto-bias circuit: once it is factory set,
no additional adjustment is required. The
auto-bias circuit will “lock in” the idle
current of each bank of two KT150 output
tubes approximately two minutes after
the REF160M is turned on, and continually
compensates to maintain the proper bias as
the tubes age. Auto-bias sets the idle current
at 65mA per tube.

It is always recommended owners purchase
replacement tubes from Audio Research

Corp. and have them installed by a qualied

technician. Since the auto bias adjusts
pairs of tubes, not each individual tube, it
is important that matched sets of four KT
150 output tubes be installed for optimum
performance and longest tube life.

Hour Counter

An LCD hour counter of elapsed tube
operating time can be viewed on the back
panel. 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. Next to the
hour counter is a recessed 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.

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. While your Reference 160M will sound
fantastic out of the box, it will only improve
with continued use.

The auto bias circuit will not accommodate
output tubes with extremely high or low
plate current readings. Aftermarket tubes
may not be tested to the same rigorous
standards as Audio Research tests, so care
must be exercised when aftermarket tubes

are installed by a qualied technician.

If uncertain about aftermarket tube
requirements, please contact Audio Research
Customer Service for recommendations.

14

Maintenance

Vacuum Tubes

It is recommended that a qualied

technician replace the vacuum tubes of your
Reference 160M 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 of a 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 placing an order. KT150
tubes should be replaced at approximately
3000 hours. 6H30 tubes should be replaced
before 4000 hours.

Servicing

Because of its careful design and
exacting standards of manufacture, your

Reference 160M amplier should normally

require only minimal service such as

periodic tube replacement by a qualied

technician, to maintain its high level
of performance.

Caution

Your Reference 160M 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.

If you have additional questions regarding
the operation, maintenance or servicing of

your amplier, please contact the Customer

Support Department of Audio Research
Corporation at [e-mail]
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)

microber 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 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
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.

15

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 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.

Audio Research Corporation does not
warrant compatibility of Audio Research
products with future operating systems and/
or hardware of other manufacturers.

16

REF160M Specications

POWER OUTPUT: 140 watts continuous from 20Hz to 20kHz. 1kHz total harmonic distortion
typically 1% at 140 watts, below 0.04% at 1 watt. (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 critical)

POWER BANDWIDTH: (-3dB points) 5Hz to 70kHz.

FREQUENCY RESPONSE: (-3dB points at 1 watt) 0.5Hz to 110 kHz.

INPUT SENSITIVITY: 2.4V RMS Balanced for rated output. (25.5 dB gain into 8 ohms)

INPUT IMPEDANCE: 300K ohms Balanced, 100K ohms Single Ended.

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

POWER REQUIREMENTS: 105-130VAC 60Hz (210-250VAC 50Hz) 400 watts at rated output,

700 watts maximum, 260 watts at “idle”, 1 watt o

TUBES REQUIRED: 2 matched pair KT150 (Power output V1-4); 2 6H30 (Gain stage V5 and V6);

DIMENSIONS:

width 17.25" (43.8 cm)
height 10" (25.4 cm)
depth 18.5" (47 cm)
handles

extended 19.25" (48.9 cm)

WEIGHT: 56 lbs. (25.5 kg) Net; 73 lbs. (33.2 kg) Shipping

17

Specications subject to change without notice.

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