What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





Audio Research SP-10

 Four Critical Performance Areas
The SP-10 have been widely acclaimed as representing the state-of-the-art. In music reproduction and each of these preamplifiers can provide the critical listener with true reference sound quality in the four critical areas of performance.
Clarity - Providing a clarity of sound that immediately impresses the listener. Audio Research preamplifiers are totally absent of the "heaviness" or "veiling" of sound present in other designs. There is also a notable lack of "hardness", "edge" and "grain" that masks fine detail in other preamplifiers.
High Definition _ While other preamplifiers obscure important musical information, Audio research preamplifiers reproduce all of the subtle colors, shadings and ambient detail that create the illusion of a "you are There" performance. The SP-10 effortlessly sort through complex musical material placing every instrument and voice onto the proper acoustic stage. This High Definition quality is a hallmark of all Audio Research products.
Harmonic Integrity - Audio Research preamplifiers provide the listener with a unique sense of "harmonic rightness". Delicate harmonic structures essential to musical accuracy remain wholly intact, creating a musical performance with a sense of "aliveness".
Dynamic Expression - Audio Research preamplifiers ecel in reproducing a musically accurate dynamic range. Highly stable power supplies and essentially overload-proof output sections result in preamplifiers that reproduce the guietest notes to the loudest and most complex musical passages. Separation of instruments and voices remains intact at every level without "smearing" or collapse of sound field.

Features
Automatic muting for continuous protection
Front panel muting for repeat settings, interruptions, etc.
Front panel power switch for activating 1600 watt capacity back-chassis, plug-in power receptacles.
Selectable front panel impedance matching for optimizing moving coil and moving magnet cartridge performance
Front panel gain selection for matching low output or high output cartridges
Front panel "bypass" switch for optimizing performance
Sonically selected components and near military grade construction
Specifications
Frequency Response:
High Level :  + .25 dB; 5 Hz - 30 kHz
Magnetic Phono :  + ,25 dB of RIAA, 30 Hz - 40 kHz
Harmonic Distortion:  less than ,01% at 2V RMS output, 20 Hz -20 kHz
Input Impedance: 
High Level :  50 k Ω, all inputs
Magnetic Phono :  10,30, 100, 10 k, 47 k Ω (selectable)
Noise:
High Level :  250 µV RMS maximum residual unweighted wideband noise
Magnetic Phono :  2 µV  RMS above 1 kHz
Dimensions (W x Hx D):  19" x 5,25" x 10,25"

Audio Research SP-8

 The single greatest requirement of a preamplifier is to amplify the given signal input without adding or subtracting musical information. This extremely complex, intricately defined, highly dynamic signal creates heavy demands on a preamplifier. Only Audio Research preamplifiers so accurately meet these demands that they transmit the listener beyond the reproduction chain to experience the "live event".
For optimum signal amplification the SP-8 utilize vacuum tube audio circuitry. While the transistor has replaced the vacuum tube in most popular consumer electronics, the vacuum tube still offers a number of design adventages over solid-state devices.  The vacuum tube has ceratin unique electrical properties that make it highly attractive for use in quality audio electronics.
Audio Research continues to incorporate the vacuum tube in its designs many years after tube technology was considered impractical. However, experience dictates that for state-of-the-art. Music reproduction the vacuum tube is difficult to surpass. Because of its long-term involvement in vacuum tube design Audio Research  is regarded as the leader in vacuum tube technology.

Features
Automatic muting for continuous protection
Manual muting for repeat settings,interruptions, etc.
Front panel power switch for activating 1600 watt capacity back-chassis, plug-in power receptacles.
High accuracy, close tracking segmented gain control
Sonically selected components for optimum sound performance
Near military grade construction used throughout.
Specifications
Frequency Response:
High Level :  + .25 dB; 5 Hz - 30 kHz
Magnetic Phono :  + ,25 dB of RIAA, 30 Hz - 40 kHz
Harmonic Distortion:  less than ,01% at 2V RMS output, 20 Hz -20 kHz
Input Impedance:  50 k Ω, all inputs
Noise:
High Level :  250 µV RMS maximum residual unweighted wideband noise
Magnetic Phono :  5 µV maximum equivalent input noise, wideband RMS
Dimensions (W x Hx D):  19" x 5,25" x 10,25"

Linn Majik-I

 The Linn Majik-I control amplifier uses microprocessor control, Linn's solid state input switching and volume control technology, and the latest surface mount manufacturing techniques to deliver unprecedented audio performance and ease of use.
The Majik-I accommodates six input sources, and provides outputs for two tape decks. 
Separate pre-amp output and power amp inputs provide exceptional flexibility, and offer the possibility of an economical upgrade to active susystems. Two sets of speaker sockets facilitate bi-wiring. Future options will include multi-room modules and a tuner which will simply plug into the internal expansion port.

Like any electronic product, the Majik-I will perform at its best when used with the highest quality source. The better the sound from your turntable, tuner or CD player, the better the sound you will hear from the other components in the system.
Specifications:
Preamplifier Section
Sensitivities for 0,7V RMS at line Output , 1 kHz into 2 k Ω load
Inputs Sensitivity/Load:
Phono MM :  3,1 mV /47 k Ω /68 pF
Tuner, CD, Aux, Tape :  300 mV / 10 k Ω
Outputs:
Tape (Equal to Aux input level, unity gain): 
Output Impedance:  100 Ω
Minimum Load :  5 k Ω
Line Output:
Output Impedance :  200 Ω
Minimum Load (on line outputs):  1 k Ω total
Headphone:
Output Impedance :  less than 8 Ω
Output Level :  Same as preamp output level
Output Current Limit :  60 mA
Load Impedance :  8 to 2000 Ω
Power Amplifier Section
Power Output:
66 W per channel into 4 Ω
33 W per channel into 8 Ω
Input Impedance:  10 k Ω
Voltage Gain:  28,5 dB
Input Sensitivity:  592 mV RMS for 16,2 V RMS output (33 W into 8 Ω)
General:
Power Consumption:  320 VA max.  25 Watts idling
Mains Supply Fuse:
100 V and 115 V :  T6, 3A antisurge
230 V :  T3, 15A antisurge
Main Supply Tolerance:  Nominal ± 10% with no performance change
Dimensions (W x H x d):  320 x 80 x 326mm
Weight:  4,9 kg

SAE TWO R3C

 Start out on the right receiver - SEA TWO R3C
If you're about to build a superb hi-fi system, you need a strong start. We recommend the R3C.
Pream, amp and AM/FM tuner. It's all the electronics you need in one compact, self-contained unit.
And it has features normally associated with receivers twice the price.
Examples: Loudness compensation to let you hear full bass and highs at low volume. Separate tuning and signal strength meters. They virtually guarantee perfectly accuraate tuning.
R3C - For a great system, start here.

Features
30 watts RMS per channel at 8 ohms from 20 Hz to 20 kHz with lesss than 0,09% THD
Separate signal strength and center of channel meters for precise tuning.
Full low and high frequency loudness compensation.
A low filter for rumble protection.
R3C Specifications
Power Rated (at 8 Ω, 20-20,000 Hz):  30 W per channel
Total Harmonic Distortion:  0,09%
Intermodulation Distortion:  0,09%
Signal-to-Noise Ratio (IHF):
Phono :  -78 dB
Aux :  -96 dB
Overload:
Phono :  better than 125 mV
Aux :  better than 3 V
Sensitivity:
Phono : 2,5 mV
Aux :  150 mV
Frequency Response:
Phono :  ±0,5 dB
Aux :  ±0,25 dB
Loudness Compensation
At  100 Hz :  +8 dB
At 10 kHz :  +4 dB
Volume Control Tracking:  +1
AM Tuner Section
Usable Sensitivity (IHF):  20 µV
Total Harmonic Distortion:  5% (10 mV at 1 kHz)
FM Tuner Section
Usable Sensitivity (IHF):
Mono :  11,2 dBf (2,0 µV)
Stereo :  19,2 dBf (5,0 µV)
50 dB Quieting:
Mono :  19,2 dBf (5,0 µV)
Stereo :  37,3 dBf (40 µV)
Total harmonic Distortion:
Mono :  0,15 %
Stereo :  0,25 %
Stereo Separation :
At 1 kHz :  40 dB
At 10 kHz :  35 dB
IF Rejection:  80 dB
Dimensions (W x H x D):  442 x 135 x 354 mm (17,4 " x 5,31" x 14")

SAE TWO C3A

 The amazing, effortless, integrated amplifier. An amp and pre-amp all in one - SAE TWO C3A
Most integrated amps pick one thing and do it pretty well. Well, that's not enough for the C3A.
It can handle two tape recorders, with the ability to dub from either one to the other. But it's not just flexible. It's easy. Extra large, stepped volume control provides precise,graduated adjustment. Front panel headphoe jack makes private listening simple.
There's even an audio muting capability to adjust the amp to varying efficiencies of speakers.
C3A. It can do anything you can do.

Features:
50 watts RMS per channel at 8 ohms from 20 Hz to 20 kHz with no more than 0,05% THD
Provisions for two tape recorders with full tape dubbing
Full high and low frequency loudness compensation
40 step attenuator-type volume control
C3A Specifications
Power Rated (at 8 Ω, 20-20,000 Hz):  50 W per channel
Total Harmonic Distortion:  0,05%
Intermodulation Distortion:  0,05%
Signal-to-Noise Ratio (IHF):
Phono :  -85 dB
Aux :  -97 dB
Overload:
Phono :  better than 150 mV
Aux :  better than 4 V
Sensitivity:
Phono : 2,5 mV
Aux :  150 mV
Frequency Response:
Phono :  ±0,25 dB
Aux :  ±0,25 dB
Loudness Compensation
At  100 Hz :  +8 dB
At 10 kHz :  +4 dB
Volume Control Tracking:  +0,5
Dimensions (W x H x D):  442 x 135 x 354 mm (17,4 " x 5,31" x 14")

SAE TWO T3U

 The tuner that's accurate. In it's own quiet way - SAE TWO T3U
An extremely wide, linear dial scale makes perfectly accurate tuning of FM stations as easy as a flick of the wrist. Then once you get there, a step quieting slope makes sure nothing comes through but the station. FM muting plus hi-blend for low noise make sure there's no doubt about it.
A tuning meter helps you visually to achieve the perfect center of the channel. You'll see signal strength. Not just hear it.
T3U. Use it with the integrated amp and you have a super high quality electronic system.

Features:
Linear tuning scale for precise tuning
Steep quieting with 37,3 dBf (40 microvolt) sensitivity for 50 dB S/N
Linear phase filters for excellent separation - 45 dB at 1 kHz
FET input for low overload and high sensitivity 10,3 dBf (1,8 microvolt)
T3U Specifications
AM Tuner Section
Usable Sensitivity (IHF):  20 µV
Total Harmonic Distortion:  5% (10 mV at 1 kHz)
FM Tuner Section
Usable Sensitivity (IHF):
Mono :  10,3 dBf (1,8 µV)
Stereo :  14,7 dBf (3,0 µV)
50 dB Quieting:
Mono :  14,7 dBf (3,0 µV)
Stereo :  37,3 dBf (40 µV)
Total harmonic Distortion:
Mono :  0,1 %
Stereo :  0,2 %
Stereo Separation :
At 1 kHz :  45 dB
At 10 kHz :  35 dB
IF Rejection:  90 dB
Dimensions (W x H x D):  442 x 135 x 354 mm (17,4 " x 5,31" x 14")

SAE TWO C3D

 The cassette deck with a mind of its own - SAE TWO C3D
What's gotten into the C3D? A microcomputer chip. A chip that will prevent you from accidentally misusing the controls, and from stretching or tearing tape. A chip with a memory for finding a predesignated spot on a cassette. It's full, solenoid-operated logic control. There's more ; Dolby noise reduction, switches for maximum utilization of latest tape formulations, and optional accessory remote control.
The C3D. What a mind.

Features:
30 Hz - 18 kHz linear response within ±3 dB
Full-logic tape control system
DC-Servo motor for low wow/flutter - less than 0,06%
3 Step Bias and EQ switches
C3D Specification
Frequency Response: 
FeCr, CrO₂ : 30 Hz - 18 kHz ±3 dB
Standard tape :  30 Hz - 15 kHz ±3 b
Wow and Flutter:  0,06%
Input Sensitivity/Impedance:
Mic :  0,25 mV/10 k Ω
Line :  30 mV/20 k Ω
Signal-to-Noise Ratio (ref. Dolby level):
Dolby ON
FeCr, CrO₂ :  -64 dB
Standard tape :  -61 dB
Dolby OFF
FeCr, CrO₂ :  -56 dB
Standard tape :  -50 dB
Distortion (O VU at 1 kHz):  1,3%
Dimensions (W x H x D):  442 x 135 x 354 mm (17,4 " x 5,31" x 14")

Aiwa XA-007


Specifications XA-007
Power Section
Effective Output Power:
80 W +80 W at 4 Ω, (THD 0,9%, 1kHz)
60 W +60 W at 8 Ω,  (THD 0,9%, 1kHz)
Total Harmonic Distortion:  0,02% (20Hz - 20kHz, 40 W, 8Ω)
Output Bandwidth:  20 Hz - 200 kHz (less than 0,05%)
Frequency Response:  5 Hz - 100 kHz,  0 dB -3 dB
Pre-amp Section
S/N Ratio (IHF A curve short circuited):
Phono MM : 94 dB (5 mV input)
Phono MC :  75 dB (0,5 mV Input)
Tuner, DAT, Aux, Tape:  105 dB
Input Sensitivity/Impedance:
Phono MM : 2,5 mV/47 kΩ
Phono MC :  0,2 mV/100 Ω
Tuner, DAT, Aux, Tape, CD : 150 mV/47 kΩ
Phono MM Overload level:  150 mV (1kHz, THD 0,01%)
Output Level/Impedance:
Tape/DAT : 150 mV/47 kΩ
Headphones : 8 - 32 ohms
Speakers : 4 -16 Ω  (A + B : 8 - 16 Ω )
RIAA Deviation:  ±0,5 dB (30Hz - 15kHz)
Power Requirements [E,Z]:  Switchable 120/220/240 V, 50/60 Hz [220 V, 50 Hz]
Power Consumption [E,K,Z /H]:  350 W/ 125 W
Dimensions (W x H x D):  430 x 140 x 335 mm

Weight:  8,4 kg

Sony TA-3200F


Specifications
Power Amplifier Section
Dynamic Power Output (IHF):  
320 watts, both channels opearting at 8 ohms
500 watts, both channels operating at 4 ohms
Continuous RMS Power:
Rated Output:
140/140 watts ,  at 8 ohms
200/200 watts ,  at 4 ohms
Per Channel Operating:
110 + 110 watts, at 8 ohms
130 + 130 watts, at 4 ohms
Both Channel Driven Simultaneously:
At 20 - 20,000 Hz :  100 + 100 watts at 8 Ω
Power Bandwidth (IHF):  5 Hz to 35 kHz
Harmonic Distortion (20 Hz - 20 kHz):  
Less than 0,1% at rated output
Less than 0,05% at 1 watt output
IM Distortion:  
Less  than 0,1% at rated output\
Less than 0,05% at 1 watt output
Frequency Response:  5 Hz - 200 kHz +0 -2 dB (at 1 watt output)
Input Impedance:  75 k Ω
Input Sensitivity (for rated output):  1,4 V
Output Impedance:  4 - 16 Ω
Signal-to-Noise Ratio:  better than 110 dB
Residual Noise:  less than 0,003 µW (8 ohm)
General
Power Consumption:  280 watts (at 120 V)
Power Requirements:  100, 120, 220, 240 V AC 50/60 Hz
AC Outlets:  1 x Switched; 1 x Unswitched (total 300 watts)
Dimensions ( W x H x D):  400 x 149 x 323 mm (15-3/4" x 5-7/8" x 12-3/4")
Weight [Net/ Shipping]:  14,0 kg / 16,7 kg (30 lb 10 oz / 36 lb 14 oz)

KEF Chorale

 Chorale (1970-79)
The Chorale paired a B200 with the established T27 tweeter in a 20 Litre closed box design, which became an instant success and KEF’s new best selling product. It combined an extended high frequency response with a natural, uncoloured midrange and a full round, bass - quiet and delicate or complex and heavy music being handled with equal ease. The success of the Chorale ensured that it remained in production until 1979.
Specification: Chorale
System type: Two-way, bookshelf/stand-mount
Enclosure type: Closed box
Size: 470 x 280 x 220 mm (18.5 x 11 x 8.7 inches)
Weight: 7.5kg (16.5lb)
Input Impedance: 8 ohms
Rated maximum power: 25W programme
Amplifier Requirements: 15-25 watts per channel into 8 ohms
System resonance: 55Hz
Frequency range: 35-40,000Hz
Finishes: Walnut, Teak, White
Grille: Brown Grey, Beige
System: SP1016
Drive units: B200 bass unit (SP1014), T27 tweeter (SP1032)

Crossover: SP1015

KEF Concerto

 Concerto (1969 - 77)
The Concerto, released in 1969, was KEFs latest high quality three-way loudspeaker system. It maintained the KEF practice in high end systems of using a dedicated midrange driver to cover the critical vocal range, in this case the newly developed 5 bextrene coned B110. Together with the new T27 ¾” melinex domed tweeter and the established B139 bass driver, it offered full range reproduction with low distortion, high power capacity and wide dispersion.

Intended for professionals and serious enthusiasts, the Concerto became a major success and remained in production until 1977 when it was superseded by the Cantata.

Specification: Concerto
System type: Three-way, floor standing
Enclosure type: Reflex
Size: 28 x 17 x 12 inches (711 x 432 x 305 mm)
Weight: 50 lb (22.7kg)
Input impedance: 8 ohms
Power rating: 30W
Crossover frequencies: 400, 3500Hz
Frequency range: 30-30,000Hz
System: A6614
Drive units: B139 bass unit (A6171), B110 midrange unit (A6362), T27 tweeter (A6340)
Crossover: A6606
System: SP1005
Drive units: B139 bass unit (A6171), B110 midrange unit (A6362), T27 tweeter (A6340)
Crossover: SP1002
System: SP1006
Drive units: B139 bass unit (A6171), B110 midrange unit (SP1003), T27 tweeter (SP1032)

Crossover: SP1004

KEF Cadenza

 Cadenza (1970-76)
The Cadenza combined a B200 with the established T27 tweeter and BD139 passive radiator in a 45 Litre design, a format that was later developed into the Reference 104. Although relatively compact the Cadenza was suitable for use in larger rooms and was capable of fundamental tones down to 30Hz. This was achieved by means of the acoustically coupled passive radiator, which worked in conjunction with the bass driver to enhance the bass output.

Specification: Cadenza
System type: Two-way, stand-mount/floor standing
Enclosure type: Passive radiator
Size: 597 x 362 x 299cm (23.5 x 14.25 x 11.75 inches)
Weight: 15kg (33 lb)
Input Impedance: 8 ohms
Rated maximum power: 30W programme
Amplifier Requirements: 15-30 watts per channel into 8 ohms
System resonance: 35Hz, mechanical reflex
Frequency range: 30-40,000Hz
Crossover Frequency: 3500Hz
Finishes: Walnut, Teak, White
Grille: Brown Grey, Beige
System: SP1024
Drive units: B200 bass unit (SP1022), BD139 passive radiator (SP1023, 1037 or 1042), T27 tweeter (SP1032)

Crossover: SP1019

JBL SA 600

 Solid State Amplifier / Preamplifier
Recognized by all leading test organizations and audio publictions as the finest complete amplifier available. Absolutely lowest noise. Intrinsic distortion lower than the residual distortion of the finest test instruments. This award-winning design features professional quality controls, and the JBL T-Circuit for a sonically transparent, conservatively rated 40 watts per channel. Built-in Aural Null system permits perfect stereo balancing. 

 The SA-600 Amplifier consist of three major functional sections.
These are: The two-channel preamplifier contained on a single, large circuit board, the two separate power amplifiers on identical circuit boards, and the power supply.
Each preamplifier has five inputs any one of four are selected by the Sellector Switch. The main output of each preamplifier is coupled to a power amplifier. An auxiliary preamplifier output is available at the :Out to Recorder Jack". A separate "Tape Play" input is provided, bypassing the slector switch and "Out to Recorder" jack.
The two power amplifier circuit boards ahare a cast heat sink with common power supply. The channel A power amplifier is on the top and the channel B is underneath.
The power supply uses silicon diodes and provides +23 volts DC regulated for the preamplifier and six balanced plus and minus supply levels to the power amplifiers. The power supply common return is chassis ground.
 Special Features:
Built-in JBL Aural Null stereo balancing system for simple, exact balancing of stereo installation.
Three-position phono switch for best possible signal-to-noise ratio.
Tape monitor switch for direct comparison of program source with recorded signal while recording.
Front panel stereo headphone jack.
Specifications:
(All specifications are measured with both channels operating simultaneously into 8 Ω loads. AC line voltage is held to 117 volts, 60 cycles. During normal use, the performance of the SA-600 is not appreciably affected by line voltage fluctuations between 110 and 127 volts.)

Power Output:
80 watts continuous RMS power;
40 watts per channel, at any frequency from 10 cps to 30,000 cps
Frequency Response:
From high level inputs : ±0,75 dB (20 - 20,000 cps);  ±1,5 dB (10 - 130,000 cps)
Power amplifier only (measured at test point provided) :  ±0,25 dB (20 - 20,000 cps);  ±1,5 dB (3 - 200,000 cps)
Harmonic Distortion:
From High level Inputs :  less than 0,2% (20 - 20,000 cps at 80 watts or any level less than 80 watts);  less than 0,1% (20 - 20,000 cps at one watt)
Power Amplifier Only :  less than 0,15% (20 - 20,000 cps at 80 watts or any level less than 80 watts)
Intermodulation Distortion:
From High level Inputs :  less than 0,2% (at 80 watts or any level less than 80 watts); 
less than 0,07% (at one watt)
Power Amplifier Only :  less than 0,15% (at 80 watts or any level less than 80 watts)
Sensitivity (Signal required for rated output):
Phono Input (at 1,000 cps reference) :  4, 8 or 16 mV into 47 k Ω, switch selected
Tape Head Input (at 500 cps reference) :  2 mV into 47 k Ω
High Level Input :  0,25 V into 30 k Ω
Maximum Phono Signal:  250 mV at 1,000 cps with less than 0,1% harmonic distortion. The highest output magnetic cartridges available will not overload the input stages of the SA-600
Hum and Noise:
Through both preamplifier and power amplifier : 
Low level inputs (1 k Ω termination) :  72 dB below rated output, equivalent to 1 mV at input terminals or 80 dB below 10 mV.
(These specifications are measured with the phono switch set a t Low, giving rated output with 4 mV signal. With switch set at Med. Or High noise is further reduced to 75 dB or 78 dB below rated output, respectively. )
High level inputs :  85 dB below rated output.
Transient Response:  rise time measured at high level inputs is 2,5 ms from 10% to 90% of square wave signal at 160 watts peak power or any lower power level.
Power amplifier only 2,0 ms at 160 watts peak power or any lower power level.
Response to such square wave signals is free from detectable overshoot or ringing, as observed on an oscilloscope.
Overload Recovery:   less than 1/10 of one cycle to recover from 100% single cycle overload at any frequency from 20 to 20,000 cps.
Output Impedance:  8 Ω rated impedance, 4 to 16 Ω nominal impedance.
(when driving a 16 Ω load, the SA-600 meets all published specifications except that power output is reduced to 64 watts. Wen driving a 4 Ω load the SA-600 produces 130 watts of undistorted power for brief periodes of time.  Prolonged operation at more than 40 watts per channel however will trigger the built-in automatic overload devices.
Stability:  The SA-600 is completely stable when connected to any loudspeaker system or even to a capactive load, AC line surges do not affect the stability of the circuit.
Short Circuit Protection:  Absolute, The SA-600 cannot be damaged by accidental or intentional short or open circuit at the output terminals, or by any degree of impedance mismatch.
Transistors:  36 silicon transistors plus 19 silicon diodes.

Dimensions (W x H x D):  16-3/16" x 5-1/16" x 13-3/4"

JBL SG 520

 A perfectionist's instrument, featuring unparalleled flexibility of inputs, outputs, mixing, and professional linear actuated controls, the Graphic Controller offers the flatest frequency response, lowest distortion, lowest noise level and greatest operating convenience of any preamplifier. Additional controls, tape monitor switch and convenience inputs and outputs are located behind special hinged front panel.
 Special Features:
Professional linear-actuated controls allow precise adjustment and give instant visual recognition of exact settings. Illuminated push-buttons permit instantaneous switching from any function to any other function. Seledom-used controls are concealed behind a hinged lower panel, out of sight when not needed, yet directly accessible from the front.
Included in the secondary control bank are output level set controls, gain controls for both phono inputs, high frequency filter, low frequency filter, tape monitor witch, and an auxiliary "trim" balance control for the phono input. (Whit this, the residual unbalance in any particular pickup cartridge can be eliminated without disturbing normal settings for other program material) the hinged panel also conceals input and output jacks for convenient connection of temporary auxiliary equipment.
 Aural Null Stereo Balancing System
By adding the F22 remote relay (available as an accessory), the Graphic Controller becomes more than a fine stereo control center ,  it can be used as a sensitive instrument for balancing channels and checking the performance of your stereo component installation.
Specifications:
(All specifications are measured with AC line voltage of 117 volts at 60 cycles. Line voltage fluctuations between 105 and 127 volts do not affect the performance at the Graphic Controller.)

Output:  3 Volts (more than sufficient to drive a JBL Energizer or any conventional power amplifier)
Frequency Response:  Typical response is within ¼ dB through the entire audible range from 20 - 20,000 cps. (the smallest deviation which can be detected by the human ear is approximately one dB.)
Distortion (these are typical specifications under ambient temperatures which would normally be encountered in a home installation):
Total Harmonic Distortion  (at full rated output):  less than 0,15% at any frequency from 20 - 20,000 cps
Intermodulation Distortion:  less than 0,05% at 3 volts output
Hum and Noise:  1 mV or less referred to the low level phono input. From high level inputs, noise is 90 dB below rated output.
Gain: 
Low level inputs:  54 dB
High level inputs:  2 dB (require 0,3 volts for rated output)
Tone Controls:
Treble :  17 dB boost or cut at 20,000 cps
Bass :  21 dB boost or cut at 20 cps
Control Tracking Accuracy: 
Through their full range of operation, the linear actuated controls of the Sg-520 exhibit variations typically less than one decibel from laboratory specifications. This means that you enjoy the unlimited flexibility of continuously variable controls, yet with a degree of tracking accuracy normally obtainable only with individual calibrated switch-type attenuators.
Tempearature Stability:
The SG-520 is considerably less sensitive to temperature changes than ordinary transistorized preamplifiers. So long as sufficient ventilation is provided to keep air temperature in its immediate vicinity below 110° F, it can be left on indefinitely without affecting the quoted specifiactions.

Dimensions (W x H x D):  15-9/16" x 6-1/2" x 13"