The SP11 is
a hybrid unit, utilizing both vacuum tubes and FETs (Fiel Effect Transistors).
It is not intended that this product should somehow continue the controversy of
"vacuum tubes" vs. "solid-state". Rather, in keeping wit
Audio Research's design philosophy of advancing the state-of-the-art., each
type of device is used where it performs best.
One
important result, aside from the dramatically improved quality of sound
reproduction, is the use of only six vacuum tubes - tubes which need not be
selected low-noise types. A significantly longer time between tube replacement
is also expected.
As a last
word, this preamplifier may well change your thinking about music reproduction.
Because it is so incredibly "open" sounding, much information not
previously sudible is available, providing new insight and enjoyment from many
sound sources. To be appreciated, the SP11 preamplifier must be personally
experienced; it cannot otherwise be adequately related.
Operational
Features:
Automatic
warmup, brown-out power-line interruption muting and manual muting at all
preamplifier outputs, with new shunt circuitry.
Subsonic
phono filter with 6 dB /oct rolloff (to eliminate ringing) with transition to
12 dB/octave.
Bypass
switch for use with "audiophile quality" program material.
Absolute
phase switch for main outputs, plus unswitched inverting and non-inverting
outputs.
Full tape
functions; two inputs, two recording outputs, plus tape copy and tape monitor
functions.
Input/output
connectors have heavy gold plating and connect "ground" before
"hot".
Level set
control in addition to normal gain control. Allows essentially unlimited input
signal range while preserving optimum gain control usage.
Toroid power
transformer for low mechanical noise and low external magnetic field.
In Octobr of
1985, Audio Research Corporation introduced the SP11 preamplifier. During the
first year, our introductory claim of "a
new reference standard" has been confirmed by reviewer after
reviewer throughout the Free World.. It is improbable that any audio product,
including previous Audio research products, has ever received such unanimous
acclaim. We believe that once you hear the SP11 reproduce music, you will find
that acclaim justified.
Specifications
Frequency
Response:
High Level
Input : 0,2 Hz to 100 kHz ±1 dB (-3 dB
below 0,1 Hz and above 200 kHz)
Phono
Input: 20 Hz to 40 kHz ±2 dB of RIAA (±1
dB of RIAA, 1,0 Hz to 100 kHz)
Harmonic
Distortion: less than 0,005% at 2 V RMS
output, 5 Hz to 20 kHz (Typically less than 0,001% at midband, phono or line
input)
Intermodulation
Distortion: less than 0,003% at 2 V RMS
output
Gain (aat 1
kHz , bypass mode):
Phono Input
to Tape Output : 46 dB (0,2V output from
1mV input)
Phono Input
to Main Output : 75 dB (0,175 mV input
for 1 V output)
High Level
Input to Main Output : 29 dB (36 mV
input for 1 V output)
Inputs: Phono, Tuner, CD, Video, Spare, Tape 1, Tape
2,
Outputs: Tape 1, Tape 2, Main 1, Main 2, Direct,
Invert
Filter: 25 Hz Hi-pass phono subsonic 6 dB/octave
rolloff (to eliminate ringing) with transition to 12 dB/octave at 10 Hz. Front
panel switchable, phono only
Controls: Gain, level (to set gain Range), balance,
Mode, Input, Impedance
Switches:
Tape Monitor, Copy, Tape 1/2, Tape 1 to 2/2 to 1, Mute, Invert Phase,Bypass,
Filter
Input
Impedance:
Phono : 47 k Ω, 100, 30, 10, 3 Ω (front panel
selectable)
Phono Input
Capacitance: 150 pF at 10 kHz
High
Level: 20 k Ω or higher, depending on
switch functions
Maximum
Inputs Level Undistorted:
Phono : 350 mV RMS at 1 kHz, 1200 mV RMS at 10 kHz
(0,1 second maximum duration, 6 dB less if continuous)
High Level
: 25 Volts RMS
Output
Impedance: 250 Ω main, direct, invert
outputs, 500 Ω tape output. Recommended load 60 k Ω and 100 pF (25 k Ω minimum,
1000 pF maximum)
Rated
Output: 2V RMS 1 Hz to 100 kHz main,
direct, invert outputs (Maximum 80 V RMS output at 0,2% T.H.D. at 1 kHz into 60
k Ω load with 2,85 V RMS high level input)
Phase:
Tape
Outputs, Direct Output; Non-inverting
Invert
Output : Inverting
Main Outputs
: selectable non-inverting or inverting.
All outputs may be used simultaneously.
Noise (IHF
Weighted, shorted input):
Output (Gain
down) : 6 µV (110 dB below rated output)
Input High
Level) : 3 µV equivalent input (110 dB
below 1 V input)
Phono : 0,15 µV equivalent input (76 dB below 1 mV
input)
Tube
Complement (Hybrid FET/Tube Audio Circuit, Solid-State Power Supply): 6 - 6DJ8/ECC88
Power
Requirements: 95 - 135 V AC 60 Hz
(Export 190 - 270 v AC 50/60 Hz)
Power
Consumption: 130 watts maximum
Dimensions
(W x H x D) Each Chassis, EIA Rack panel Mounting:
480 x 134 x
260 mm (19" x 5,25" x 10,25")
Weight Net:
SP11 : 6,4 kg (14 lbs)
SP11PS
: 6,8 kg (15 lbs)