Audio Research SP9MKII User manual

audio research
H I G H D E F I N I T I O N"
3900 ANNAPOLIS LANE NORTH I PLYMOUTH, MINNESOTA 5544 7-544 7 I PHONE: [phone] FAX [phone]
MODEL SP9MKII PREAMPLIFIER
OWNER'S MANUAL
5-11-89

TABLE OF CONTENTS
SECTION
PREFACE
INTRODUCTION
WARNINGS
PACKAGING
DESCRIPTION OF CONTROLS
CONNECTIONS
INSTALLATION INSTRUCTIONS
OPERATING PROCEDURE
INPUT IMPEDANCE ADJUSTMENT
REDUCING GAIN
SERVICING
CLEANING
WARRANTY TERMS AND CONDITIONS
WARRANTY OUTSIDE THE USA
SPECIFICATIONS
ADDENDUM: SCHEMATIC AND PARTS LIST
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12

PREFACE
Please take the time to carefully read this Instruction Manual prior to installation or use
of your SP9 Mark II 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 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.
INTRODUCTION
The SP9 hybrid stereo preamplifier has been an overwhelming success since its introduction
in June 1987, allowing a glimpse of truly high-end musical reproduction to thousands of
music lovers on a budget. The original SP9 was a simplified adaptation of the hybrid
technology which first appeared in the groundbreaking SPll, a two piece unit which
strikingly redefined The State-of-the Art.
In the two years that have followed, the hybrid technology has been developed and refined
further, as evidenced by the SP15 and SP14 preamplifiers which have picked up where the
SPll left off, and continue to define the state-of-the art.
With the knowledge gained during these two years, and sonic references redefined, we are
proud to announce the Mark II revision to the SP9 preamplifier
Technically, the Mark II version of the SP9 preamplifier includes a group of 14 different
improvements, utilizing 61 component and wire changes. These combine to provide enhanced
_reliability and flexibility, in addition to the sonic improvements.
*
*
*
In the CD input the gain has been reduced by 12 dB, allowing operation of
the gain control in its mid rotation or high positions, while still leaving
all other inputs with normal gain for lower input program sources.
Low-level hum in the line section is reduced 10-20 dB, which is noticeable
primarily in systems with high-efficiency speakers, small ''live'' rooms,
high-gain power amps, or low-noise CD program sources.
The power supply and phono sections are ''beefed up'' to prevent accidental
damage if a CD source is mistakenly connected to the MC phono inputs and is
played at a high level, even with the mute on.
Sonically, the perspective of the SP9 has changed. If one thought of the original SP9 as
a simpler SPll, then the Mark II can be thought of as a junior SP14. The SP9 Mark II is
sweeter and more lucid, exhibiting less electronic glare or grain, while resolving more
detail than before. Images are better defined in a more three-dimensional soundstage,
emerging from a blacker background. Combining this with greater dynamic contrasts makes
the complete presentation much more vivid and lifelife.
A pleasant result of these refinements is that the SP9 Mark II can be interfaced more
successfully with less expensive amplification. Introducing the SP9 Mark II into modest
audio systems will bring startling improvements not previously thought possible with this
level of investment. The exceptional value of the SP9 Mark II is refreshing in today's
crowded marketplace. 1

In short, the SP9 Mark II hybrid preamplifier is a product you can be proud to own and enjoy
for years to come, without fear that it will soon become technically obsolete or
sonically dated. Taking the time to carefully read and understand the remainder of
this Owner's Manual will help insure you get all the enjoyment your SP9 is capable
of. Happy listening!
WARNINGS
l. To prevent fire, or shock hazard, do not expose your SP9 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 SP9 is equipped with an 18-guage, 3-conductor cable and
a standard three-prong grounding plug. In addition, your SP9 uses an isolating power
transformer with 4 KV-rated insulation. For absolute protection, do not defeat the
ground power plug. This provides powerline grounding of the SP9 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.
PACKAGING
Save all packaging in a dry place away from fire hazard. Your SP9 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 SP9 from unnecessary damage or delay.
Note that your SP9
retention sockets.
for shipment.
has been shipped with vacuum tubes installed in their proper high-
You may do likewise if the complete original packaging is used
DESCRIPTION OF CONTROLS
GAIN CONTROL: A high-quality, metal-film segmented control with 31 steps and
accurate tracking. Use it to control loudness or volume. Rotation to the left attenuates
gain, rotation to the right increases gain. Best sonic performance and best signal-to-
noise ratio will result if the input signal and amplifier input sensitivity allow normal
listening when GAIN is set between 10 o'clock and 2 o'clock.
With some high-efficiency loudspeakers, a high-output source such as a CD player, and
with a high-gain amplifier lacking an input volume control, you may discover that normal
listening is only possible with the GAIN control barely on, or in the 9 o'clock position.
In such circumstances it is possible to reduce the overall gain of the SP9 by 6dB, by
making a simple internal adjustment. See the ADJUSTMENTS Section of this Manual, or
contact your Audio Research dealer for assistance.
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BALANCE CONTROL: When rotated, adjusts the relative sound levels of the left and right
channels. The 12 o'clock position marks the point of equal balance. Rotating the knob
to the right decreases the level of the left channel proportionally, shifting the sonic
image to the right. Rotating the knob to the left shifts the sonic image to the left.
MODE CONTROL: Allows selection of various single-channel (mono) and two-channel (stereo)
listening modes. Detents mark each selection option during rotation of knob. ''Mono''
reproduces identical sonic information in both right and left channels. ''Reverse''
switches left-channel information to the right, right-channel information to the left.
"Stereo" is the normally preferred mode for most program material, producing the most
realistic spacial image. "Left" cancels all right-channel information and presents
left-channel information to both channels. In the same way, "Right" cancels all left-
channel information, etc.
INPUT SELECTOR: Detents mark selection of various source material options: "Phono" for
phonograph record turntables; "Tuner" for AM/FM radio tuners; "CD" for compact di gi tal
disc players; "Video'' for input from Beta or VHS videotape recorder/players; and ''Spare''
for any additional high level source: tape, tuner, CD, video, etc.
The signal source chosen by the input selector is
Recorder 2 outputs when the Monitor/Source switch
description of Monitor/Source switch, next page.)
selector is always fed to the Recorder 1/Recorder
overridden.
fed to the Main and Recorder 1/
is set to "Source." (See
The source chosen by the input
2 outputs, and cannot be
POWER SWITCH: Supplies power from AC wall outlet to SP9 when in "Power" position.
Although not strictly necessary, it is nonetheless good practice to put the SP9 in "Mute"
before turning on power for maximum protection of your power amplifier(s) and speakers.
MUTE/OPERATE SWITCH: In ''Mute'' position, shorts the main outputs of the preamplifier to
allow listening interruptions for telephone answering or other reasons. This switch
should always be activated between listening uses or switching of inputs, in addition to
turning the Gain (volume) control counter-clockwise. These two simple precautions will
prevent inadvertent misuse of your SP9 and help protect your power amplifier(s) and
speakers from unexpected transient signal pulses (tone arm mishandling, etc). In
''Operate'' position, this switch allows the signal to pass normally to the outputs.
CAUTION: Do not turn up the gain control beyond normal listening positions when the
SP9 is in the Mute mode. Always turn the gain control down when changing program sources
even when it is muted. The SP9 has an extremely wide dynamic range, and switching to '
Operate at loud levels may be too much for amplifiers, speakers or ears. Furthermore,
at extremely high signal levels (such as from a severe blow to the turntable or tone arm)
in the Mute mode, the SP9 may overload internally. This will not harm the SP9, but it
may take 10-15 seconds to stabilize from the overload. If you switch to Operate before
the SP9 has recovered from the over1oad, you wi l hear a "pop" when the mute switch is
actuated, indicating the presence of unwanted subsonic energy that may damage some
amplifiers and poorly-fused speakers, if the SP9 is left in Operate. If you hear a
"pop," switch immediately back to Mute, turn down the gain control and wait 15 seconds
or so and try again. Under normal conditions the SP9 muting has no "pops." (Turntable
rumble, record warp wow or other subsonic program energy may also cause small, harmless
mute ''pops.'' These ''pops'' may be eliminated by turning down the SP9 gain control
before muting.)
-3-

POWER/MUTING CIRCUIT LED: Glows green to indicate unit is on and receiving power from
the power supply. Note that for approximately 45 seconds after start-up or in "Mute"
mode, this LED will glow more dimly, indicating proper operation of the muting circuit.
In the ''Operate'' mode (after warm-up), the LED brightens and your SP9 is ready for
normal operation.
MONITOR/SOURCE SWITCH: In ''Monitor'' position, this switch ''bypasses'' the Input Selector
and presents the signal to the main outputs from sources (tape recorders, etc.) connected
to the "Tape l" or "Tape 2" input jacks on the rear panel. In the "source" position, the
program source is controlled by the Input Selector (Phono, Tuner, CD, etc.).
TAPE 1/TAPE 2 SWITCH: Usable only when "Monitor" has been selected. Selects either
''Tape l'' or ''Tape 2'' inputs and connects that choice to the main outputs (through the
"high level" amplification circuitry).
CONNECTIONS
INPUT CONNECTORS: All are clearly marked to indicate use. All high level inputs are
5OK ohms impedance. Remember that impedance of "Phono" input is control led by soldered-
in resistor values on the main circuit board (see INPUT IMPEDANCE ADJUSTMENT).
MAIN OUTPUT CONNECTORS: There is one (l) set of output connectors, which should be
connected to your electronic crossover or power amplifier.
The input impedance (load) of the power amplifier or electronic crossover to the
SP9 main outputs should be at least 2OK ohms for maximum sonic benefit.
NOTE: At the performance level of the SP9, high-quality audio signal interconnect cables
are critical to preserving maximum fidelity. Audio Research RFI-shielded or unshielded
interconnect cables are highly recommended for connection to your power amplifier( s) and
to other ancillary equipment. See your authorized Audio Research dealer for recommended
lengths and prices.
RECORDER 1/RECORDER 2 OUTPUT CONNECTORS. Two (2) sets are provided. Recorder outputs
should be connected to your recorder's "AUX" or "LINE" inputs. These outputs supply a
source of whatever is selected by the Input Selector Control. Level is non-variable
and approximately the same as the selected input source.
All input/output connectors have heavy gold plating and connect "ground" before "hot."
(On disconnect, ''hot'' is first.)
INSTALLATION INSTRUCTIONS
While the SP9 does not dissipate an unusual amount of heat, it is important that it be
provided with 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.
l. Upright and horizontal mounting is suggested if extended operation (longer than one
hour) is contemplated.
-4-

2. Do not ''stack'' the SP9 on top of a power amplifier.
overheating, but "hum" may be introduced into the phono
of the amplifier's power transformer.
Not only could this cause
circuits from the proximity
3. Do not place or operate your SP9 on a soft or irregular surface such as a rug.
This will prevent proper ventilation.
4. Do not operate your SP9 without the top and bottom covers installed. These are
required both for safety as well as shielding from interference (except in service
operations, obviously).
5. If rack mounting is employed, use Audio Research Rack Mount Ventilators (RMV-3)
below and above your SP9.
6. If side-by-side mounting with other equipment is employed, place the SP9 to the
right of the other chassis, so as to provide maximum spacing between another power
transformer and the SP9's sensitive phono input circuitry.
7. In a cabinet or rack-mount installation which has an enclosed back, an exhaust fan
is desirable so as not to operate the SP9 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 PROCEDURE
START-UP:
l. Make sure Power switch is set to "Off" position; Mute switch should be in "Mute"
position; and "Gain" Control should be at minimum (full counter-clockwise rotation).
2. Secure all rear-panel connections between SP9, power amplifier(s) and input sources.
Note: Given the advanced performance capabilities of the SP9, it is extremely important
that high-quality interconnects be used for connection to ancillary electronics. Audio
Research brand interconnects, in either unshielded or RFI-shielded configurations, are
strongly recommended. Your Audio Research dealer can assist you in determining optimal
lengths for your system.
3. Plug 3-prong powerline cord from rear of SP9 into grounded AC wall receptacle.
4. Turn Power switch to "On." Green LED will glow _dimly for approximately 45 seconds
while power supply stabilizes, indicating operation of automatic muting circuit. After
this warm-up muting period, the LED will brighten when ''Operate'' is selected, indicating
that your SP9 is ready for operation.
Note: For superior sonic performance, a warm-up period of at least one hour is recommended.
In addition, your SP9 may be safely left ''on'' continuously for maximum performance at all
times, but at the expense of higher maintenance costs (more frequent tube replacement).
5. Rotate input selector to source desired; set switch options to positions desired.
6. If ''Phono'' has been selected, make sure impedance is properly matched to your phono
cartridge (see INPUT IMPEDANCE ADJUSTMENT).
7. Activate input source, then deactivate Mute switch and adjust Gain Control as necessary
-5-

TAPE DUBBING PROCEDURE:
When using the SP9 as a control center for recording, the program source to be dubbed
must be connected to one of the five inputs controlled by the front Input selector.
This routes the selected program to the Recorder l/Recorder 2 outputs, which should
connect to the ''aux'' or ''hi-level'' inputs on the recorder(s). (Check to make sure
your recorder doesn't short its inputs when it's not in ''record'' mode. If it does,
it may severely load or distort the SP9's output signal.)
The Tape l/Tape 2 inputs are for listening or monitoring only through the main outputs,
and cannot be routed to the Recorder l/Recorder 2 outputs for dubbing. When using these
inputs, your tape recorder should be switched to "Tape" or "Monitor," if it has separate
record and play heads. This allows true "A-8" comparison of signals before and after
recording, using the Monitor/Source switch on the SP9.
Two recorders may be used simultaneously to record the same program. While dubbing is
in process, the signal from either of the Tape l or Tape 2 inputs may be listened to
by switching to "Monitor" and selecting the appropriate Tape l or Tape 2 input.
Switching back to "Source" returns the listener to the program being dubbed.
Two different programs may be recorded simultaneously by routing one program directly
from its source to the recorder (bypassing the SP9) and routing the other source
through the SP9 and its Recorder outputs. Then, two different programs may be
monitored through the Tape l and Tape 2 inputs.
If you wish to use a tape unit both as a program source to be dubbed and as a recorder
with monitoring provisions, then use "Y" connectors to feed both Spare and Tape l inputs
on the SP9 from the recorder outputs. Then either function may be selected without
changing connections. Remember that if you accidently select the output of your
recorder as a signal source and send this same signal back to the same recorder's
inputs, you may generate an ''echo loop'' or wild oscillations, depending on the gain
settings on the recorder.
MUTING PROVISIONS:
The SP9 has several prov1s1ons to help protect against misuse of the exceptional dynamic
range and wide bandwidth that it offers. It is not subject to damage itself, but some
power amplifiers and speakers are more limited in their ability to withstand signal
extremes. These provisions, both manual and automatic, are designed not to interfere
with a flawless listening experience of unprecedented realism, while giving reasonable
protection against warm-up surges and power line interruptions. However, for absolute
protection of associated equipment some operator understanding, and responsibility,
is required.
Initial "settling" time of all circuit parameters within the SP9 requires approximately
5 to 10 minutes. The automatic muting circuitry timer is adjusted for about 45 seconds.
(This is because recurrent interruption "settling" time is much less. You would not
want to wait for 5-10 minutes each time such an interruption occurred.)
The Mute/Operate Switch allows manual disabling of the SP9 outputs during any moving of
the tonearm or switching of equipment. Use of this switch will minimize stress on your
amplifier even if it is ''off." It is also highly reconnended that manual muting be
employed during the initial 45 second warm-up period as well as during turn-off for
maximum protection.
-6-

While it is true that the automatic muting will provide reasonably adequate protection
against speaker burnout during these periods, it has limitations. At the 45 second
point the automatic timer ''releases'' the output, and since full subsonic stabilization
has not yet occurred, some sonic unpleasantness may occur. Although this is normally
adequate protection, utilization of the manual mute provision will completely avoid
this stress to your speakers, as well as the associated sonic unpleasantness.
Some solid-state power amplifiers have a DC offset present at their input connections.
(This, of course, should not be.) Operation of the manual muting switch with such an
amplifier connected will result in a "click" or "pop" in your loudspeaker (commensurate
in level with the amount of the offset) each time the switch is activated. Repair or
replacement of such amplifiers is suggested.
The automatic muting operates as follows:
1. The manual mute switch always disables both "main" outputs and overrides any automatic
provisions, even when the SP9 is turned off. (The ''Operate'' position of the manual mute
switch is functional only when the unit is not in the automatic mute mode.)
2. The 45 second warm-up timer will restart automatically and the LED will dim if the
power is temporarily interrupted for 0.1 second or more. Note: Power supply regulation
of the SP9 is effective down to lOOVAC without serious sonic degredation.
3. The automatic muting of the SP9 is designed to be effective only against power line
interruptions and power supply failures. It will not mute against subsonic signal
transmissions from your turntable, etc. Proper furng of speakers is essential to
protect against excessive audio level or power amplifier faults.
SHUT-DOWN:
1. Set "Mute" switch to "mute" position.
2. Rotate ''Gain'' control counter-clockwise to minimum setting.
3. Deactivate power amplifier(s).
4. Deactivate al 1 input sources.
5. Set SP9 Power Switch to ''Off'' position.
INPUT IMPEDANCE ADJUSTMENT
For the best sonic performance of your phone pickup cartridge, it should connect to the
proper load impedance recommended by the cartridge manufacturer. Your SP9 comes wired
with a standard load of 47K ohms for most high-output moving-coil, or moving magnet
cartridges. A kit of precision load resistors is supplied with your SP9 for the more
common low-impedance load requirements of 10, 33 or 100 ohms for typical low to medium
output moving-coil cartridges. Consult your cartridge manufacturer or dealer to
determine the optimum load impedance for your needs. You may wish to connect the load
resistors at the output of your turntable, rather than in the SP9, especially if you
may be using more than one turntable or cartridge, with different load requirements.
-7-

The use of prec1s1on fixed resistors provides better load accuracy and sonic performance
at lower cost than most adjustable or switchable loads. Audio Research can supply
audiophile grade non-standard load resistor and capacitor values upon request accompanied
by $10.00 to cover order processing costs (certified funds or money order).
Solder the desired resistors to the turret terminal posts on the bottom of the main
circuit board near the phono inputs (see illustration). First wrap the resistor leads
around the posts 1/2 to 3/4 turn. Then solder using the special alloy solder supplied
with the resistors. Connect one resistor between the left and center posts and the
other resistor between the center and right posts.
For 10 ohms use brown-black-black-gold resistors. For 33 ohms use orange-orange-
red-gold resistors. For 100 ohms use brown-black-black-black resistors.
NOTE: All SP9s have two 560 picofarrad capacitors mounted on the impedance loading
pegs, one for each channel. When using moving coil cartridges these capacitors should
not be removed when adding load resistors. The load resistors should be installed in
parallel with these capacitors.
INPUT CAPACITANCE ADJUSTMENT
The SP9 has a total input capacitance of 600 Picofarrads with the 560 picofarrad
capacitors installed and 40 picofarrads without them. Different value capacitors can
be installed to match the requirements of your moving magnet cartridge. Observe the
polarity as shown in diagram below when adding capacitors.
REDUCING GAi N
SP9
Bottom view,
rear corner.
0
0
,~ 560 pF capacitors
l I + +
Wrap, solder resistors to turret terminals.
When using the SP9 with high-output cartridges or high-sensitivity power amplifiers or
high-efficiency speakers, you may find that you typically set the SP9 Gain control at
9-11 01clock, where the detented gain increments may be too large for setting the
desired listening volume. For more precise setting of the desired listening level,
the SP9 includes a simple internal provision to reduce the gain of the line section
by 6d8. This affects all signal sources, when using the normal Main Output jacks.
The signal level at the Recorder Output jacks is unaffected. Note: the CD input of the
SP9 Mark II has a built-in gain reduction of 12 dB. Other line inputs have normal gain.
To reduce the gain by 6dB, merely remove the bottom cover and unsolder the gain change
connection for each channel. These connections are located in the central area of the
bottom of the main circuit board near V2, where the pads identified by the letter
11
A
11
connect to the large central ground path.
To restore the SP9 to its original gain, merely resolder across these small gaps at
11
A.
11
For best results use the special alloy solder supplied with the cartridge load
resistor kit.
8

SERVICING
Because of its careful design and exacting standards of manufacture, your SP9 should
normally require only minimal routine service to maintain its high level of performance.
CAUTION: Your SP9 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 two (2) vacuum tubes inside your SP9 are quality 6DJ8 types, and with normal use
should not need to be changed for approximately 5,000 to 10,000 hours of use. Replacement
6DJ8 tubes need not be low-noise or matched for gain characteristics, and are
available from Audio Research.
At the back of the Manual you will find a schematic diagram for your SP9 which is fully
annotated with operating voltages and component part values. Your service technician
will require this information when servicing your unit.
CLEANING
To maintain the visual appearance of your SP9 preamplifier, occasionally wipe the front
panel and top cover surfaces with a soft, damp (not wet) cloth to remove dust. Amild,
non-alkaline soap solution may be used to remove fingerprints or similar smudges.
Cleaners containing abrasives should not be used as they will damage the ''brushed''
grain of the front panel finish.
-9-

3-YEAR LIMITED WARRANTY TERMS AND CONDITIONS
l. LIMITED WARRANTY. Audio Research warrants the product designated herein to be
free of manufacturing defects in material and workmanship, subject to the conditions
hereinafter set forth, for a period of three (3) years from the date of purchase by
the original purchaser or no later than five (5) years from the date of shipment to
the authorized Audio Research dealer, whichever comes first, excepting vacuum tubes
which are warranted for 90 days only (See 6).
2. CONDITIONS. This Warranty is subject to the following conditions and limitations.
The Warranty is void and inapplicable if the product has been used or handled other
than in accordance with the instructions in the owner's manual, abused or misused,
damaged by accident or neglect or in being transported, or the defect is due to the
product being repaired or tampered with by anyone other than Audio Research or an
authorized Audio Research repair center. The product must be packed and returned to
Audio Research or an authorized Audio Research repair center by the customer at his
or her sole expense. Audio Research will pay return freight of its choice. A RETURNED
PRODUCT MUST BE ACCOMPANIED BY A WRITTEN DESCRIPTION OF THE DEFECT AND A PHOTOCOPY OF
THE ORIGINAL PURCHASE RECEIPT. This receipt must clearly list model and serial number,
the date of purchase, the name and address of the purchaser and authorized dealer and
the price paid by the purchaser. Audio Research reserves the right to modify the design
of any product without obligation to purchasers of previously manufactured products and
to change the prices or specifications of any product without notice or obligation to
any person.
3. REMEDY. In the event the above product fails to meet the above Warranty and the
above conditions have been met, the purchaser's sole remedy under this Limited Warranty
shall be to return the product to Audio Research or an authorized Audio Research repair
center where the defect will be rectified without charge for parts or labor, except
vacuum tubes (See 6).
4. LIMITED TO ORIGINAL PURCHASER. This Warranty is for the sole benefit of the
original purchaser of the covered product and shall not be transferred to a subsequent
purchaser of the product.
5. DURATION OF WARRANTY. This Warranty expires on the third anniversary of the date
of purchase or no later than the fifth anniversary of the date of shipment to the
authorized Audio Research dealer, whichever comes first.
6. VACUUM TUBES. Vacuum tubes are warranted for the original 90-day period only.
7. DEMONSTRATION EQUIPMENT. Equipment used by an authorized dealer for demonstration
purposes is warranted to be free of manufacturing defects in materials and workmanship
for a period of three (3) years from the date of shipment to the dealer. Vacuum tubes
are warranted for 90 days. Demo equipment needing warranty service must be packed and
returned to Audio Research by the dealer at his sole expense. Audio Research will pay
return freight of its choice. A returned product must be accompanied by a written
description of the defect on an AUDIO RESEARCH RETURNED GOODS AUTHORIZATION form.
Dealer-owned demonstration equipment sold at retail within three (3) years of date of
shipment to the dealer is warranted to the first retail customer to be free of
manufacturing defects in materials and workmanship for the duration of the 3-Year
Limited Warranty remaining (as measured from the date of shipment of the equipment
to the dealer). Vacuum tubes are not warranted for any period under these conditions
of sale. In the event warranty service is needed under the conditions, the owner of
-10-

the equipment must provide a copy of his purchase receipt, fulfilling the requirements
described under ''2. Conditions'' above. The product must be packed and returned to
Audio Research or an authorized Audio Research repair center by the customer at his or
her sole expense. Audio Research will pay return freight of its choice.
8. MISCELLANEOUS. ANY IMPLIED WARRANTIES RELATING TO THE ABOVE PRODUCT SHALL BE
LIMITED TO THE DURATION OF THIS WARRANTY. THE WARRANTY DOES NOT EXTEND TO ANY
INCIDENTAL OR CONSEQUENTIAL COSTS OR DAMAGES TO THE PURCHASER. Some states do
not allow limitations on how long an implied warranty lasts or an exclusion or
limitation of incidental or consequential damages, so the above limitations or
exclusions may not apply to you. This Warranty gives you specific legal rights,
and you may also have other rights which vary from state to state.
9. WARRANTOR. Inquiries regarding the above Limited Warranty may be sent to the
following address:
WARRANTY OUTSIDE THE USA
audio research
HIGH DEFINITION"
5 7 40 GREEN CIRCLE DRIVE
MINNETONKA. MINNESOTA 55343 .. 4424
Audio Research has formal distribution in many of the countries of the free world.
In each country the Audio Research Importer has contractually accepted the
responsibility for product warranty. Warranty should normally be obtained from
the importing dealer or distributor from whom you obtain your product.
In the unlikely event of service need beyond the capability of the Importer,
Audio Research does, of course, back up the warranty. Such product would need
to be returned to Audio Research, together with a photostatic copy of the bill
of sale.
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SP9 MARK II SPECIFICATIONS
Frequency response:
High level section:
Phono:
Distortion:
±.5dB, 5Hz to 50kHz
-3dB points below lHz and above 200kHz
±.3dB of RIAA, 30Hz to 40kHz
Less than .01% at 2V RMS output. (Typically less than .005% in midband)
Gain:
Phono input to tape output: 46dB
Phono input to main output: 67dB
Input Impedance:
High level inputs to tape output:
High level inputs to main output:
C.D. input to main output:
OdB
2ldB
9 dB
50K ohms Line Inputs; 47K phono (Phono provisions for any value below 47K ohms
or added input capacitance for matching certain magnetic cartridges.)
Output Impedance:
250 ohms main output; 850 ohms recorder output. Recommended load 60K ohms
and lOOpF. (20K ohms minimum and lOOOpF maximum)
Maximum Inputs:
Phono, 200mV at lkHz (lOOOmV RMS, lOkHz). High level inputs essentially
overload-proof.
Rated Outputs:
2V RMS 5Hz to 50kHz, all outputs, 60K ohm load (main output capability is 50V RMS
output at 1/2% THD at lkHz into a lOOK ohm load with 5V RMS high level input)
Power Supplies:
Electronically-regulated low
Shielded toroid transformer.
Noise:
High Level
and high voltage supplies and electronic decoupling.
Line regulation better than .01%
(1) 70uV RMS maximum residual unweighted wideband noise at main output
with gain control minimum (98dB below 5V RMS output)
(2) More than lOOdB below lV RMS input (Less than 7uV equivalent input noise)
Phono:
0.12uV equivalent input noise, !HF weighted, shorted input (78dB below lmV input)
Tube Complement:
2 - 6DJ8/ECC88 dual triodes
(Hybrid FET/Tube audio circuit, solid-state power supply)
Power Requirements:
100-135VAC 60Hz (200-270VAC 50/60Hz) 50 Watts
Dimensions:
19" (48 cm) Wx 5 1/4" (13.4 cm) H (standard rack panel) x 10 1/4" (26 cm) 0.
Handles extend 1 5/8'' (4.1 cm) forward of front panel. Rear chassis fittings
extend 7/8'' (2.3 cm)
Weight:
13 lbs. (5.9 kg) Net; 22 lbs. (10kg) Shipping
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