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Model SP9 MKIII
Operating Procedure
Start-Up:
1.
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 MK.III, power amplifier(s) and input sources.
Note: Given the advanced performance capabili-
ties of the SP9 MKIII. it is extremely important
that high-quality interconnects be used for con-
nection to ancillary electronics. Audio Research
brand interconnects, in either unshielded or RFI-
shielded configurations, are strongly recommend-
ed. Your Audio Research dealer can assist you in
determining optimal lengths for your system.
3. Plug 3-prong powerline cord from rear of
SP9 MK.III into grounded AC wall receptacle.
4. Turn Power switch to "On". Green LED will glow
dlmly for approximately 45 seconds while power
supply stabilizes, indicating operation of automat-
ic muting drcuit. After this warm-up muting peri-
od, the LED will brighten when "Operate" is se-
lected, indicating that your SP9 MK.III is ready for
operation.
Note: For superior sonic performance, a warm-up pe-
riod of at least one hour is recommended. In addi-
tion, your SP9 MK.III may be safely left "On" con-
tinuously 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 imped-
ance is properly matched to your phone cartridge
(see INPUT IMPEDANCE ADJUSTMENT).
7. Activate input source, then deactivate Mute
switch and adjust Gain Control as necessary.
Tape Dubbing Procedure
When using the SP9 MKIII 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 pro-
gram to the Recorder I/Recorder 2 outputs, which
should connect to the "Aux" or "Hi-level" inputs on
the recorder(s). (Check to make sure that your
recorder does not short it's inputs when not in
"Record" mode. If it does. it may severely load or dis-
tort the SP9 MK.Ill's output signal.)
4
The Tape I/Tape
2
inputs are for listening or moni-
toring only through the
ma1n
outputs, and cannot be
routed to the Recorder I/Recorder 2 outputs for dub-
bing. 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-
B"
comparison of signals before and after recording,
using the Monitor/Source switch on the SP9 MK.III.
Two recorders may be used simultaneously to record
the same program. While dubbing is in process, the
signal from either of the Tape I or Tape 2 inputs
may be listened to by switching to "Monitor" and se-
lecting the appropriate Tape 1 or Tape 2 input.
Switching back to "Source" returns the listener to
the program being dubbed.
Two different programs may be recorded simultane-
ously by routing one program directly from its
source to the recorder (bypassing the SP9 MK.III) and
routing the
other
source through the SP9 MK.III and
its Recorder outputs. Then, two different programs
may be monitored through the Tape
1
and Tape 2 in-
puts.
If
you wish to use a tape unit both as a program
source to be dubbed and as a recorder with monitor-
ing provisions. then use "Y" connectors to feed both
Spare and Tape I inputs on the SP9 MK.III from the
recorder outputs. Then either function may be se-
lected 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 gener-
ate an "echo loop" or wild oscillations. depending on
the gain settings on the recorder.
Muting Provisions
The SP9 MK.III has several provisions 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 speak-
ers are more limited in their ability to withstand sig-
nal extremes. These provisions, both manual and au-
tomatic, 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 MK.III requires approximately 5 to 10 min-
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