Page 1
3900 ANNAPOLIS LANE NORTH / PLYMOUTH, MINNESOTA 55447-5447 / PHONE: 763-577-9700 FAX: 763-577-0323
www.audioresearch.com
Model
REFERENCE PHONO 2
P R E A M P L I F I E R
Owner’s Manual
Page 2
Contents
1
Model Ref Phono 2
Section Page No.
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Front Panel Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1, 2
Remote Control Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Installation Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Operating/ Start-up Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2, 3
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Disposal and Recycling Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Warranty Terms and Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Page 3
Model Ref Phono 2
FINAL / 1-09 - Ref Phono 2 - 3-19-09
VAC UUM T UBE PHO NO PR EAMP LIFIE R
RE FEREN CE P HON O 2 HIGH D E F I N I T I ON
®
INPUTPOWER
GAIN LOAD RIAA
MUTE
D I S P L A Y
RIGHT RIGHT
LEFT LEFT
LEFT OUTPUTS RIGHT OUTPUTS
TURNTABLE
GROUND
150 WATTS MAX 50/60 HZ
~
5.0A FUSE
SLO-BLO
T3.15A (230V)
REFERENCE PHONO 2
P R E A M P L I F I E R
PLYMOUTH, MINNESOTA
MADE IN U.S. A.
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
SERIAL VOLTS
50
500
CUSTOM
1K
1 0 0
LOAD
COLUMBIA
RIAA
LO GAIN
HI GAIN
MUTE
INPUT 2INPUT 1
DECCA
47K
200
HOURS POWER
REF PHONO 2
C A U T I O N
FOR PROTECTION
AGAINST FIRE HAZARD
REPLACE ONLY WITH
SAME RATING FUSES.
INPUT 1
INPUT 2
B A L A N C E D
S I N G L E
E N D E D
S I N G L E
E N D E D
B A L A N C E D
Page 4
Preface
Please take the time to carefully read this instruction manual prior to installation or use of your Ref Phono 2 phono
preamplifier. Because it is a highly advanced electronic
instrument, there are several facts and procedures you
should know before you place it in operation.
Just as you would not purchase and attempt to operate an
expensive camera, computer system or high-performance
automobile without first learning something about performance parameters and correct operating procedures, so too
your phono preamplifier requires some familiarization
before you make it part of your music reproduction system.
Your reward, in terms of maximum performance and a long
service life, will be well worth the effort.
Warnings
1. To prevent fire, or shock hazard, do not expose your Ref
Phono 2 to rain or moisture.
2. This unit contains voltages which can cause serious
injury or death. Do not operate with cover removed.
Refer servicing to your authorized Audio Research dealer
or other qualified personnel.
3. The power cord on your Ref Phono 2 is equipped with a
standa rd three-prong grounding plug. For absolute
protection,
do not defeat the ground power plug.
This
provides powerline grounding of the Ref Phono 2 chassis
to provide absolute protection from electrical shock.
4. For continued protection against fire hazard, replace the
fuse only with the same type and rating as specified at
the fuse holder.
DO NOT ATTEMPT TO OPERATE THIS
EQUIPMENT BEFORE INSTALLING THE VACUUM
TUBES IN THEIR PROPER SOCKETS.
Packaging
Sav e all pa c kagin g in a dry place aw ay fro m fire
hazard. Your Ref Phono 2 phono preamplifier 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 Ref Phono 2
from unnecessary damage or delay.
Note that your Ref Phono 2 has been shipped with the vacuum tubes installed in protective foam blocks under the top
cover. With the Ref Phono 2 unplugged, use a phillips-head
screwdriver to loosen the fastening screws, remove the top
cover and set aside. Install the numbered tubes in their respective sockets, refasten the top cover and store the foam
blocks with your carton.
Front Panel Controls
POWER ON / O F F :
The unit is off when the front panel
display (including the pilot light when in display “Off ”
mode) is completely unlit. Unit defaults to “Off” whenever
it is unplugged and then plugged in. When first plugged in
and the power switch is pressed, MUTE ON will flash on
the display for 40 seconds during the auto muting warm-up
cycle. When the MUTE ON indicator stops flashing the unit
initially defaults to INPUT 1 and is ready to operate.
MUTE:
After completion of the 40-second warm -up cycle,
pressing mute button once will unmute unit and display
will read MUTE OFF. Press mute button again to mute unit
(display will read MUTE ON.)
INPUT
: Selects INPUT 1 or INPUT 2, indicated on display.
When switching inputs, individually selected GAIN, LOAD
and RIAA/alternate Decca or Columbia EQ settings are
retained for each input position.
G A I N :
Selects between LOW (51dB BAL, 45dB SE) and
HIGH (74dB BAL, 68dB SE) gain settings. When switching
from LOW to HI GH g ain position, unit automatically
defaults to MUTE ON status each time as a precaution and
reminder to lower the volume level of your preamplifier, to
prevent possible system overload and damage to loudspeakers. The 23dB gain difference between the LOW and
HIGH gain positions is substantial.
LOAD:
Pressing the LOAD button allows the user to step
through six pre-set cartridge resistance loading options
(47K, 1000, 500, 200, 100 and 50 ohms) as well as a
cu stom value resisti ve loa ding option. Contact your
Audio Research dealer or Audio Research Customer Service
(763-577-9700) for assistance with custom loading setup
procedure. The display will indicate the currently selected
load resistance for each input setting. It is suggested that
you select the loading value nearest the cartridge manufac-
Model Ref Phono 2
FINAL / 1-09 - Ref Phono 2 - 4-16-09
1
TUBE LOCATIONS
TOP VIEW
REAR
FRONT
V 1
V 6
V 5
V 2
V 3
V 4
Page 5
turers loading recommendation to begin with and then
listen to alternate loading if desired.
Be c a use all Ref Pho no 2 front pane l fu nctio ns are
duplicated on the remote, you may listen to loading sonic
changes from the listening position by selecting different
loads via their individual buttons on the remote. (Note that
depending on the phono cartridge the volume level may
decrease as lower loading values are selected.)
RIAA:
Selects between RIAA, early COLUMBIA stereo and
early DECCA stereo LP phono equalization curves.
Remote Control Functions
In addition to all of the front panel control functions, the
remote also accesses the following functions.
DISPLAY DOWN/DISPLAY UP [DSP DN/DSP UP]:
Decreases/increases display intensity, offering 6 levels of
brightness and display “off”. If display “off” is selected, a
small pilot light remains illuminated in the center of the
display window as a reminder the unit is turned on. In
display “off” mode th e display will illuminate for 10
seconds when any button (except Power on/off) is selected,
allowing for control function navigation.
H O U R S : When pressed, displays number of operating
hours vacuum tubes have been in service. WARNING: after
replacing tubes, this function should be reset to “0” only by
a qualified technician. Hours display can be reset to “0” by
pressing square black button located on upper right corner
of vertical circuit board directly behind display window
inside of the chassis. The preamp must be “On” to reset
function–the service technician must be careful to avoid
any contact with other circuit components during reset
operation. Contact Audio Research customer service (763577-9700) for information regarding this procedure.
Connections
INPUT CONNECTORS: There are two sets of RCA input
connectors, for connecting multiple turntable/tonearm
cables.
OUTPUT CONNECTORS: There is one set of BAL and
one set of RCA
output connectors for connecting to line
inputs (Direct, Aux, Phono, Tuner, etc.) of your line
stage/preamplifier.
All input/output connectors are gold plated and RCAs
connect “ground” before “hot”. On disconnect, “hot” is disconnected first.
NOTE: A "passive" line stage is not recommended for use
with the Ref Phono 2 as it may not provide the gain necessary to amplify the output of the Ref Phono 2 to adequate
levels to the power amplifier.
Installation Instructions
While the Ref Phono 2 does not dissipate an unusual
amount of heat, it is important that it have a reasonable airflow to assure long, trouble-free operation. In addition, the
following installation guidelines will help insure maximum
sonic performance as well as reliable service.
1. Upright and h o rizon t al mou nting is req uired
if extended operation (longer than one hour) is contemplated.
2. Do not “stack” equipment on top of the Ref Phono 2 or
the Ref Phono 2 on top of other equipment: not only
could thi s ca use ove rheatin g, but “h um” may be
introduced into the phono circuits from the proximity
of the power transformer of the other equipment.
3. Do not place or operate unit on a soft or irregular surface
such as a rug. This will prevent proper ventilation.
4. Do not operate unit without the top and bottom covers
installed. These are required both for safety as well
as shielding from interference (except in service operations).
5. In a cabinet installation which has an enclosed back, an
exhaust fan is desirable so as not to operate the Ref
Phono 2 in overheated ambient air. Operation of vacuum
tube equipment for long periods of time in hot ambient
air will shorten tube life and increase chance of failure of
other component parts.
Operating/Start-up Procedure
1. Secure connections between turntable, Ref Phono 2, and
line stage preamplifier. Note: Given the advanced performance capabilities of the Ref Phono 2, it is extremely
important that high-quality interconnects be used for
connection to ancillary electronics.
2. Plug 3 -prong power cord into a groun ded A C wall
receptacle.
3. Turn Power switch “on.” The display will light and
MUTE ON will flash for approximately 40 seconds while
the power supply stabilizes, indicating operation of the
automatic muting circuit. After this warm-up period
MUTE ON will stay on, indicating the Ref Phono 2 is
ready for operation.
4. Select proper input, gain cartridge loading and EQ, then
unmute and play. (see Front Panel Controls section.)
Not e : For maxi mum s onic perf o rmanc e , a warm-up
period of at least one hour is recommended.
Servicing
Because of its careful design and exacting standards
of manufacture, your Ref Phono 2 should normally require
only minimal routine service to maintain its high level of
performance.
Model Ref Phono 2
FINAL / 1-09 - Ref Phono 2 - 3-27-09
2
Page 6
C A U T I O N : Your Ref Phono 2 contains sufficient levels of
voltage and current to be lethal. Do not tamper with a component or part inside the unit. Refer any needed service to
your authorized Audio Research dealer or other qualified
technician.
The vacuum tubes inside your Ref Phono 2 are 6H30 dual
triodes and a 6550C. With normal use they should last
approximately 2,000 to 4,000 hours.
Cleaning
To maintain the visual appearance of your Ref Phono 2
phono preamplifier, occasionally wipe the front panel and
top cover surfaces with a soft damp (not wet) cloth to remove dust. A mild, non-alkaline soap solution may be used
to remove fingerprints or similar smudges. Cleaners containing abrasives should
n o t
be used as they will damage
the “brushed” grain of the front panel finish. A dry 2-inch
pure bristle paint brush works well to remove dust from
bevels, reliefs and switches.
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.
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 th e 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.
Model Ref Phono 2
FINAL / 1-09 - Ref Phono 2 - 3-16-09
3
Page 7
Specifications
FREQUENCY RESPONSE: ±.2dB of RIAA, 10Hz to 60kHz;
3dB points below 0.5Hz and above 300kHz.
DISTORTION: .002% at 1.0V RMS 1kHz BAL output.
GAIN: Selectable 51dB (Low), 74dB (High) at 1kHz BAL;
45dB (Low), 68dB (High) at 1kHz SE. (MC & MM compatible).
BUTTONS: Front (6) Power, Input, Gain, Load, RIAA, Mute.
Remote adds
“Hours
” and “Display”.
INPUT IMPEDANCE: 47K ohms and 100pF SE. Selectable
loads: 1000, 500, 200, 100, 50 ohms and Custom.
PHONO EQUALIZATION: (Selectable) RIAA, Columbia, Decca.
POLARITY: Non-Inverting.
OUTPUT IMPEDANCE: 200 ohms SE, 400 ohms balanced.
Recommended load 50K-100K ohms and 100pF. (10K ohms
minimum and 2000pF maximum.)
MAXIMUM INPUTS: 250mV RMS at 1kHz (680 mV RMS at
10kHz).
RATED OUTPUTS: 0.5V RMS 10Hz to 20kHz, 100K ohm
load (output capability is 80V RMS BAL output at 1/2% THD at
1kHz, 40V SE.)
POWER SUPPLIES: Electronically-regulated low and high
voltage supplies. Line regulation better than .01%.
NOISE: 0.22uV equivalent input noise, IHF weighted, shorted
(Low Gain) input (73 dB below 1mV 1kHz input). 0.055uV
equivalent input noise (High Gain) (65dB below 0.1mV 1kHz
input).
TUBE COMPLEMENT: (4) 6H30 dual triodes, plus (1 each)
6H30, 6550C in power supply.
POWER REQUIREMENTS: 100-135VAC 60Hz (200-270VAC
50/60Hz) 140 watts maximum. 2W standby. Line fuse 5A
SLO BLO (T2A SLO BLO 230V).
DIMENSIONS: 19" (48 cm) W x 7" (17.8 cm) H (standard rack
panel) x 15.5" (39.4 cm) D. Handles extend 1.5" (3.8 cm)
forward of front panel.
WEIGHT: 27 lbs. (12.3 kg) Net; 38 lbs. (17.3 kg) Shipping.
Specifications subject to change witho ut not ice.
©2009 Audio Research Corporation.
Model Ref Phono 2
FINAL / 1-09 - Ref Phono 2 - 4-6-09
4
Page 8
Specifications
FREQUENCY RESPONSE: ±.2dB of RIAA, 10Hz to 60kHz;
3dB points below 0.5Hz and above 300kHz.
DISTORTION: .002% at 1.0V RMS 1kHz BAL output.
GAIN: Selectable 51dB (Low), 74dB (High) at 1kHz BAL;
45dB (Low), 68dB (High) at 1kHz SE. (MC & MM compatible).
BUTTONS: Front (6) Power, Input, Gain, Load, RIAA, Mute.
Remote adds
“Hours
” and “Display”.
INPUT IMPEDANCE: 47K ohms and 100pF SE. Additional
selectable loads: 1000, 500, 200, 100, 50 ohms and Custom.
(Custom loading value is factory set at 47K ohms unless
specified otherwise.)
PHONO EQUALIZATION: (Selectable) RIAA, Columbia, Decca.
POLARITY: Non-Inverting.
OUTPUT IMPEDANCE: 200 ohms SE, 400 ohms balanced.
Recommended load 50K-100K ohms and 100pF. (10K ohms
minimum and 2000pF maximum.)
MAXIMUM INPUTS: 250mV RMS at 1kHz (680 mV RMS
at 10kHz).
RATED OUTPUTS: 0.5V RMS 10Hz to 20kHz, 100K ohm
load (output capability is 80V RMS BAL output at 1/2% THD at
1kHz, 40V SE.)
POWER SUPPLIES: Electronically-regulated low and high
voltage supplies. Line regulation better than .01%.
NOISE: 0.22uV equivalent input noise, IHF weighted, shorted
(Low Gain) input (73 dB below 1mV 1kHz input). 0.055uV
equivalent input noise (High Gain) (65dB below 0.1mV 1kHz input).
TUBE COMPLEMENT: (4) 6H30 dual triodes, plus (1 each)
6H30, 6550C in power supply.
POWER REQUIREMENTS: 100-135VAC 60Hz (200-270VAC
50/60Hz) 140 watts maximum. 2W standby. Line fuse 5A
SLO BLO (T2A SLO BLO 230V).
DIMENSIONS: 19" (48 cm) W x 7" (17.8 cm) H (standard rack
panel) x 15.5" (39.4 cm) D. Handles extend 1.5" (3.8 cm)
forward of front panel.
WEIGHT: 27 lbs. (12.3 kg) Net; 38 lbs. (17.3 kg) Shipping.
Specifications subject to change without notice.
©2009 Audio Research Corporation.
4
Model Ref Phono 2
Page 9
Specifications
FREQUENCY RESPONSE: ±.2dB of RIAA, 10Hz to 60kHz;
3dB points below 0.5Hz and above 300kHz.
DISTORTION: .002% at 1.0V RMS 1kHz BAL output.
GAIN: Selectable 51dB (Low), 74dB (High) at 1kHz BAL;
45dB (Low), 68dB (High) at 1kHz SE. (MC & MM compatible).
BUTTONS: Front (6) Power, Input, Gain, Load, RIAA, Mute.
Remote adds
“Hours
” and “Display”.
INPUT IMPEDANCE: 47K ohms and 100pF SE. Additional
selectable loads: 1000, 500, 200, 100, 50 ohms and Custom.
(Custom loading value is factory set at 47K ohms unless
specified otherwise.)
PHONO EQUALIZATION: (Selectable) RIAA, Columbia, Decca.
POLARITY: Non-Inverting.
OUTPUT IMPEDANCE: 200 ohms SE, 400 ohms balanced.
Recommended load 50K-100K ohms and 100pF. (10K ohms
minimum and 2000pF maximum.)
MAXIMUM INPUTS: 250mV RMS at 1kHz (680 mV RMS
at 10kHz).
RATED OUTPUTS: 0.5V RMS 10Hz to 20kHz, 100K ohm
load (output capability is 80V RMS BAL output at 1/2% THD at
1kHz, 40V SE.)
POWER SUPPLIES: Electronically-regulated low and high
voltage supplies. Line regulation better than .01%.
NOISE: 0.22uV equivalent input noise, IHF weighted, shorted
(Low Gain) input (73 dB below 1mV 1kHz input). 0.055uV
equivalent input noise (High Gain) (65dB below 0.1mV 1kHz input).
TUBE COMPLEMENT: (4) 6H30 dual triodes, plus (1 each)
6H30, 6550C in power supply.
POWER REQUIREMENTS: 100-135VAC 60Hz (200-270VAC
50/60Hz) 140 watts maximum. 2W standby. Line fuse 5A
SLO BLO (T2A SLO BLO 230V).
DIMENSIONS: 19" (48 cm) W x 7" (17.8 cm) H (standard rack
panel) x 15.5" (39.4 cm) D. Handles extend 1.5" (3.8 cm)
forward of front panel.
WEIGHT: 27 lbs. (12.3 kg) Net; 38 lbs. (17.3 kg) Shipping.
Specifications subject to change without notice.
©2009 Audio Research Corporation.
Model Ref Phono 2
Page 10
5
USB
XLR
BNC
INVERT
OPT
PLAY/
PAUSE
STOP
RCA
MUTEPOWER
USB INTERFACE
DAC7
ln
l
|
|
n
50
500
CUSTOM
1K
1 0 0
LOAD
COLUMBIA
RIAA
LO GAIN
HI GAIN
MUTE
INPUT 2INPUT 1
DECCA
47K
200
HOURS POWER
REF PHONO 2
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