audio research ARC I50 Integrated Amplifier Instruction Manual
- June 6, 2024
- audio research
Table of Contents
HIGH DEFINITION
Thank You.
Thank you for choosing the I/50 Integrated to be a part of your music
listening system. Since 1970, Audio Research has been creating some of the
world’s finest 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 integrated amplifier. Once installed, please allow an
appropriate break-in period to fully appreciate the sonic performance this
integrated will provide to your system.
After reading the user guide, if you have any further questions regarding your
I/50, contact your dealer or Audio Research customer service – they will be
happy to help you make the most of your new component. Happy Listening!
SAFETY
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The lightning flash with arrowhead symbol with 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 sufficient magnitude to constitute a risk of
electric shock to persons.
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| The exclamation point within an equilateral triangle is intended to alert
the user to the presence of important operating
and maintenance (service) instructions in the literature accompanying the
product.
| The 3 wavy lines symbol within an equilateral triangle is intended to alert
the user to the presence of a hot surface on
the exterior case of the product.
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Read these instructions.
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Keep these instructions.
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Heed all warnings.
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Follow all instructions.
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Do not use this apparatus near water.
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Clean only with a soft, damp (not wet) cloth.
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Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
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Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
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Do not defeat the purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding-type plug has two blades and a third grounding prong. The wide blade or the third prong is provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for the replacement of the obsolete outlet.
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Warning: The apparatus shall be connected to a main socket outlet with a protective earthing connection.
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protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit
from the apparatus. -
Only use attachments/accessories specified by the manufacturer.
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Unplug this apparatus during lightning storms or when unused for long periods of time.
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Refer all servicing to qualified 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.
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WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE. DO NOT EXPOSE THIS APPARATUS TO DRIPPING OR SPLASHING AND NO OBJECTS FILLED WITH LIQUIDS, SUCH AS VASES, SHOULD NOT BE PLACED ON THE APPARATUS.
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TO COMPLETELY DISCONNECT THIS APPARATUS FROM THE AC MAINS, DISCONNECT THE POWER SUPPLY CORD FROM THE AC RECEPTACLE.
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THE MAIN PLUG OF THE POWER SUPPLY CORD SHALL REMAIN READILY ACCESSIBLE.
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The user-replaceable rear panel fuse of the I/50 shall only be replaced with a fuse of the correct breaking capacity and voltage rating as specified below and on the rear panel of the amplifier.
100-127V| T5AL250V MDQ| (ARC part 34600501)
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220-240V| T3.15AL250V| (ARC part 34600301) -
Speaker terminal banana jacks are plugged/capped for units sold in countries where this is required due to power cord plug pin shape.
WARNINGS
To prevent fire, or shock hazards, do not expose your I/50 to rain or
moisture.
Do not place objects containing liquids on top of this unit.
This unit contains voltages that can cause serious injury or death. Do not
operate with covers removed. Refer servicing to your authorized Audio Research
dealer or other qualified personnel.
The detachable power cord on your I/50 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 I/50 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. The power button on the front of
this unit, when off, does not disconnect all power from this unit. This unit
is in sleep mode when not on.
For continued protection against fire hazards, replace the fuse only with the
same type and rating as specified at the fuse holder (see page 19 for fuse
information). This unit is RoHS compliant.
A note about packaging…
Save all packaging in a dry place away from fire hazards. Your I/50 amplifier
is a precision electronic instrument and should be properly cartooned 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 I/50 from
unnecessary damage or delay.
INSTALLATION
Before operating the I/50
Your I/50 amplifier is shipped with the vacuum tubes packed in a separate
foam-lined carton. These must be unpacked and installed before you attempt to
operate the amplifier. Included are three 6922 tubes for the input and driver
stages, and a matched pair of 6550WE for the amplification output stage.
Proceed according to the following instructions.
Remove tube 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 tube pins to the socket holes. Retain the
tube carton with other packing materials for possible future use. Refasten
tube cover on the I/50.
In your system
To ensure normal component life and safe operation this unit must be operated
only in an upright position. Adequate airflow 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 amplifier from
spurious vibrations. For upright stability and best performance, never operate
the unit while it is sitting on a soft surface such as a rug or carpet.
Due to its weight (40 lbs/18.1kg), this amplifier must be supported on a
surface specifically 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 airflow above and to each side of the unit is provided.
Audio Research recommends a minimum of 6-8 inches (15-20 cm) of clearance
above the I/50 to maintain proper ambient operating temperature. It is not
recommended to operate the I/50 in an enclosed cabinet.
The ‘ambient’ operating temperature should never exceed 120° F or 49° C.
Improper installation will cause premature tube failure and will affect your
warranty, as well as the service life of the unit.
It is normal for a vacuum tube amplifier 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 affected
thereby, providing the requirements outlined above are adhered to.
A Note about Vacuum Tubes
The vacuum tubes in your I/50 have been burned in, tested and electrically
matched to provide the best performance and reliability of your amplifier.
That said, vacuum tubes must be replaced from time to time. The 6922 tubes in
the I/50 should have an expected life of approximately 4,000 hours, while the
6550WE tube in the power amplifier should have a life expectancy of
approximately 2,000 hours. These life expectancies are only approximate. The
damper rings on the 6922 tubes may be reused.
Important: When replacing vacuum tubes, please seek assistance from your
dealer or local service shop. The bias will need to be readjusted for the new
set of installed tubes.
CONNECTIONS
Input Connectors
There are four analog inputs on the I/50: three single-ended (SE) and one
balanced (XLR) pair(s). SE 1 is substituted with the phono module in the event
it is installed. SE2 is a standard, single-ended input. ‘SE3/Pass’ is a dual
function input, designed to work as a standard (volume controlled) input or a
‘pass thru’ or unity gain, permitting the connection of a secondary
preamplifier such as a multichannel processor. ‘BL’ is the balanced input with
two XLR-type connectors. When installed, the DAC module is to the right of the
speaker connectors.
Output Connectors
Heavy-duty output terminals are provided on the rear panel for 4 or 8-ohm
speaker impedance loads. Using high-quality speaker cables, securely fasten
the (-/0) speaker lead to the appropriate (black) terminal, then the (+/4 or
8) 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 overtighten
the output terminal connectors on the amplifier (use a hex driver and tighten
snugly – do not over tighten). Follow your speaker manufacturer’s impedance
specification. The I/50 puts out the same amount of power whether the 4 or
8-ohm terminals are used.
Headphone
The I/50 has a 1/4” (6.35mm) stereo headphone jack on the top panel capable of
driving a range of headphone designs. When headphones are connected, all
outputs to the speakers are muted; please note that the amplifier section of
the I/50 remains ‘on’ when headphones are used even though it is muted. The
volume knob controls headphone volume when in use.
Impedance Matching
It is important to use as close as possible an impedance match between the
amplifier and speaker for optimum transfer of power to the speaker with
minimum distortion. In the case of speaker systems with significant variations
in impedance throughout the frequency spectrum, such as most electrostatic
types, determine the best impedance match empirically for best overall sonic
results by trying different output taps.
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.
Phono Module
When installed, the phono module replaces the ‘SE1’ input and is installed in
the Audio Module port on the left side of the I/50 (adjacent the other analog
inputs). The phono input is designed to accept moving magnet (MM) and high-
output moving coil (MC) phono cartridges. Once installed, the I/50 will
recognize the phono module; ‘PH’ will be displayed on the LexieTubes® in place
of ‘S1’ when selected.
A.C. Power Connection
It is important that the I/50 be connected via its supplied 15 amp IEC
14-gauge power cord to a secure, dedicated A.C. power receptacle. Never
connect the I/50 to convenience power receptacles on other equipment. Only use
the power switch on the top panel of the I/50 for On/Off control of the
amplifier or the power switch on the remote control.
The AC power source for the I/50 amplifier should be capable of supplying 15
amperes for 100 or 120-volt units, or 10 amperes for 220 or 240-volt units.
The I/50 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
I/50 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 qualified
technician. Caution should be taken before using custom after-market power
cords: they must be at least 14-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 other AC-powered equipment is used with the I/50 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 amplifier, through its grounded power cord. Other equipment in
the system should have some form of isolation to prevent ground loops and
associated hum.
OPERATION
Start-Up
- Secure all rear-panel connections between I/50, input sources, and speakers. For the speaker connections, it is recommended that the right channel connections (bottom) be connected first, then the left channel (top) be connected last. If you are using spade terminations, pay special attention to ensure the tips of the connectors do not touch and cause an electrical short. Ensure all vacuum tubes are installed and properly seated in their sockets.
- Plug three-prong power cord from rear of chassis into grounded AC wall outlet. Once power is applied to the unit, the control circuitry will default to standby, illuminating the LexieTubes® with a single dot in the center of each tube. The unit is ready to be powered on.
- Press the power button (either on the remote or front panel). The amplifier will begin the warm-up sequence, where a 50-second count- down will show on both LexieTubes®. The amplifier will be in mute during the warm-up time. After the warm-up sequence is complete, the unit will be in mute, ready for use.
- If powering for the first time after connecting to an AC power source, the default state is input S1 and volume at 0. When turning the I/50 on from standby, the input will be set to the last used input.
- Select input source either with the left knob, or the remote input select. Adjust the volume using the right knob, or the volume (-), (+), or mute (x) with the remote control.
Shut-Down
- Press the Power button to turn I/50 off.
- The displays show a single dot in the middle of each LexieTube® once the amplifier is in standby.
Caution: After shutdown, please wait at least three minutes before
turning the I/50 on. This time is required to allow the energy in the power
supply to dissipate. Turning the unit on prematurely could cause a tube arc or
other issue.
Note: Standby power maintains power only for the control system. It is always
indicated by a single dot on each LexieTube®. When the amplifier is not
connected to AC power, the dots in the middle of the display tubes will not be
present.
Break-in
All quality stereo equipment benefits from a break-in period; during this
time, the various components, wiring, and solder connections change as
electrical signals pass through them. While the I/50 will sound fantastic out
of the box, it will only improve with continued use.
Rotary Control Knobs
The I/50 has two microprocessor-driven rotary controls for volume, input
selection, and other limited functionality. Each rotary knob is able to rotate
or can be pressed down.
The left rotary knob selects input and allows entry into the phono control
settings. The right rotary knob controls the volume. The volume range is from
1 to 45. Pressing down on the volume knob mutes and unmutes the I/50. When
muted, the LexieTube® display will be dimmed. The inputs will appear as
follows on the LexieTube® display: S1 (SE 1 input), or PH (Phono input when
the module is installed); S2 (SE 2 input); S3 (SE 3 input), or PT (PassThru
when engaged); BL (Balanced input). See accompanying instructions with the DAC
module for an explanation of the display functions when installed.
Note: An optional Phono and/or DAC module can be installed in the I/50. The
amplifier will automatically recognize when either of these modules are
present and adds their functionality to the control system of the I50. There
is no software to install when adding modules.
Remote Control Functions
Display
Pressing the display button will cycle the LexieTubes® through various levels
of brightness. There are four levels of brightness settings. The display does
not turn all the way ‘off’.
Direct Input Selection
The four buttons for input selection are dedicated to each of the four analog
inputs – SE1/Phono, SE2, PassThru (SE3), and BL. Select your desired input by
simply selecting it on the remote control.
DAC Functions
The six DAC functions buttons will only work when the DAC module is installed.
Please see the accompanying instructions with the DAC module for further
information.
SE3/PassThru Input programming
The SE3/Pass input can be changed between a volume-controlled input like the
other analog inputs, or as a pass-thru when using the I/50 with a secondary
processor, such as a home theater processor with volume control. To change
between settings, press down and hold the ‘INPUT’ knob for three seconds. The
LexieTubes® will display ‘S3’ or ‘PT’, depending on how the unit is currently
configured (default from the factory is the SE3, volume-controlled input).
Using the ‘INPUT’ knob, turn to select between ‘PT’ and ‘S3’. Once you have
selected the desired function, press down and hold the ‘INPUT’ knob again for
three seconds to confirm your selection.
Phono Module
The phono module provides 42 dB of gain and will accommodate moving magnet
(MM) and high-output moving coil (MC) cartridge designs. The standard input
impedance is 47k Ohms.
DAC Module
The DAC module allows the I/50 to make a variety of digital connections and
decode them internally. Please see accompanying instructions with the DAC
module for further information.
MAINTENANCE
Vacuum Tubes
It is recommended that you replace the vacuum tubes of your I/50 in sets. All
of the tubes in your amplifier have been matched to have similar operating
characteristics, to provide the best sound quality and reliability. 6550WE
tubes should be replaced at approximately 2000 hours. 6922 tubes should be
replaced before 4000 hours. Upon replacing a power tube or tube set, the I/50
must be biased by a trained technician to ensure proper operating values.
Servicing
Because of its careful design and exacting standards of manufacture, your I/50
amplifier should normally require only minimal maintenance to maintain its
high level of performance.
Should you need service, please contact your authorized Audio Research dealer
or another qualified technician. For additional questions regarding the
operation, maintenance or servicing of your amplifier, please contact the
Customer Support Department of Audio Research The 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’ found under ‘Support’ at the top right of the home page.
Caution
Your I/50 amplifier contains sufficient levels of voltage and current to be lethal. Do not tamper with components or parts inside the unit. Even with the power turned off, a charge remains in the energy storage capacitors for some time.
Cleaning
To maintain the new appearance of the I/50, occasionally wipe the top panel
and LexieTubes® with a soft, damp (not wet) cloth to remove dust. Disposable
eyeglass wipes can also be used to clean these surfaces. A mild, non-alkaline
soap solution may be used to remove fingerprints or similar smudges from the
Cerakote finish. Cleaners containing abrasives should not be used as they may
damage the finish of the I/50. A small, soft paintbrush is effective in
removing dust from bevels, and other features of the front panel. Clean,
compressed air can also be used to clean the fan and other hard-to-reach
areas.
Disposal and Recycling Guidelines
To dispose of this electronic product, do not place in a 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.
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 the fulfillment 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 specific terms and remedies for the 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 the return shipment. The cost of the return shipment is the responsibility of the purchaser.
Audio Research Corporation does not warrant the compatibility of Audio Research products with future operating systems and/or hardware of other manufacturers.
SPECIFICATIONS
Power Output: 50 watts continuous from 20Hz to 20kHz. 1kHz total harmonic
distortion typically 1% per channel, below 0.1% 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 affected adversely, although from a listening standpoint this is not
critical)
Power Bandwidth: (-3dB points) 10Hz to 22kHz
Frequency Response : (-3dB points at 1 watt) 7Hz to 30kHz
Input Sensitivity : 1.25V RMS for SE input.
Input Impedance: 100K ohms Balanced, 48K ohms Single Ended
Output Polarity: Non-inverting. Balanced input pin 2+ (IEC-268)
Output Taps : 8 ohms, 4 ohms
Power Requirements: 105-130VAC 60Hz (210-250VAC 50Hz) 252 watts at rated
output.
Tubes Required : 2 matched pair 6550WE; 3-6922 (1 input, 2 driver).
Dimensions: Width 16.5” (42 cm)
Height 8.75 ” (22.5 cm)
Depth 1 3.75” (35 cm). Total depth with speaker output posts 14” (36cm)
Weight: 40 lbs (18.1 kg); 51 lbs (23.1kg) shipping weight.
SERIES
6655 Wedgwood Road North / Suite 115 / Maple Grove, MN 55311
www.audioresearch.com
Specifications are subject to change without notice. ©2021 Audio Research
Corporation. High Definition and LexieTubes are registered trademarks of Audio
Research Corporation. Reproduction of this document in part or whole is
expressly forbidden without written consent from Audio Research Corporation.