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

A&R Cambridge C200 Pre-Amp

A good sound system is more than just a set of highly impressive technical specifications, the listening quality itself is more important than a list of figures. With our 200 series audio equipment we believe we have achieved an extraordinarily good balance between performance and cost, between theoretical design and practical audio quality.
The 200 series combines the very best sound performance with superb standards of construction and a highly attractive modern appearance.
The combined system produces a notably clean and beautifully neutral sound and yet preserves a large number of undeniably useful features.
A unique mixture of careful kistening tests and quality control measures during development and production have combined to present a superbly felxible high performance sound system.

The C200 Stereo Control Unit
The C200 satisfies all the demanding criteria set by systems requiring a control unit of top quality yet with versatility and flexibility in its
Readily upgraded at some later date to keep pace with future developments in audio systems.
The C200 includes a number of useful features not always found on modern high quality pre-amplifiers.
The unit is provided with a variety of tone and signal routing controls without loss of quality in performance. The bass and treble controls are factory set for a perfectly flat response in the 12 o'colock position; soft clicks of the knobs provide a guide for nominal one decibel steps up to a maximum of five decibels boost or cut. The tone controls are non-inverting, which allows a true by-pass cancel switch to be used without phase reversal.

A switchable low frequency, sub-sonic filter is fitted to minimise the effects of possible turntable rumble; it also helps to protect small loudspeakers from low frequency overload. A mono switch is also included.
The headphone socket is driven from a separate internal high quality amplifier. Thus, whatever the final speaker system might be, headphones can always be used. The main pre-amplifier outputs are automatically muted when the headphones are plugged in . Two extra switched and fused mains outlets to IEC standards, invaluable when connecting up a complete hi-fi system, are provided at the rear of the case.

There is a choice of module cards for the two modular inputs, including low output moving coil cartridge, moving magnet cartridge and line level. The cartridge input boards have switchable load and gain facilities, access to which is through apertures underneath the unit.
A tuner input and two tape inputs are also fitted. Full tape-to-tape dubbing is possible and adjustment is provided for the tape return levels.
Within the C200, provision has been made on the output card for fitting electronic cross-over units for use with active loudspeakers. One such system, using a C200 and two SA200 power amplifiers is shown on page SA200
The C200 Control Unit is primarily intended for use with the SA 200 Power Amplifier, nevertheless it is suitable for pairing with any other high performance power amplifier if required. Also, matching it with units of the A60 series can provide a number of different, highly imaginative sound systems.

Inputs 1 and 2 : labelled Disc and Aux, are programmable and their function depends on the input boards selected.
Moving Coil Cartridge
Input Resistance (switchable):  330/100/30/10 Ω
Input Capacitance (switchable):  1/100 nF
Input Sensitivity (switchable):  60/160 µV at 1 kHz
Noise:  less than -60 dB (high Gain); less than -66 dB (low gain)
Overload Margin:  better than 38 dB
Moving Magnet Cartridge
Input Resistance (switchable):  47/30/8 kΩ
Input Capacitance (switchable):  50/150/270/370 pF
Input Sensitivity (switchable):  1,5 / 3,0 mV at 1 kHz
Noise:  less than -70 dB (high Gain); less than -75 dB (low gain)
Overload Margin:  better than 38 dB
Other Inputs - Tuner, Tape 1 and Tape 2
Input Sensitivty:  100 mV
Input Impedance:
Tuner, Aux :  20 k Ω
Tape 1 and 2 :  10 k Ω
Tape 1 and Tape 2
Nominal Output Level :  100 mV
Output Impedance :  2 k Ω
Main Output
Nominal Output Level :  1,0 V
Output Impedance :  350 k Ω
Noise (using line input):  less than -90 dB
Crosstalk (any input):  less than -60 dB at 1 kHz
Distrotion:  less than 0,01% (20 Hz -20 kHz at 1,0 V RMS)
Maximum Output:  better than 8 V RMS
Frequency Response
Via Line Inputs:  +0, -0,5 dB, (20 Hz -20 kHz)
Via Disc Inputs:  +0,25, -0,5 dB , (20 Hz -20 kHz)
High Pass Filter:  -3 dB at 30 Hz  12db/oct
Tone Controls:  ±5db at 20 Hz and 20 kHz
All stages are non-inverting providing phase integrity under all operating conditions
Power Supply
200 - 250 V AC, 48 - 63 Hz, 25V A max. The unit may be adjusted to work in the range 100 - 125 V AC.
Maximum capacity of switched AC outlets 5A RMS
Dimensions (W x H x D):  430 x 44 x 305 mm (17" x 1-3/4" x 12")
Weight:  4 kg (6,8 lbs)

A&R Cambridge SA200 Power Amp

The SA200 is a high performance stereo power amplifier that will satisfy the most demanding listening tests and measurements.
Internally the SA200 consists of two identical mono power amplifiers, each with its own separate DC power supply fed from separate secondary windings of the massive toroidal mains transformer. This design approach ensures the very best isolation between the two stereo channels without the extra weight and expense of using a second transformer.
Each amplifier channel can deliver in excess of 100 watts continuous power into 8 Ω  loads or  160 watts into 4 Ω  loads with negligible distortion. The unit will also drive well over 200 watts into 2 Ω . 

Considerable care has been taken to ensure that power output is maintained into low impedance and reactive loads. The amplifier is thus extremely tolerant of different loudspeaker loads. A bridging module is available to connect the two channels to produce over 320 watts into a single 8 Ω  speaker.
The unit is very well protected by quick acting electronic protection systems and fuses. The fuses are placed inside the feedback loops to eliminate their effect on the quality of the sound output. The sound quality is further maintained by the direct hevy duty wiring between the boards and the output terminals. A novel feature of the SA200 is the input-output comparator which detects any amplifier distortion such as clipping. It then momentarily changes the colour of the front panel indicator from green to red as a warning to the user.

The SA200 is built to the highest standards with the minimum of internal wiring. The electronics are housed inn a heavy duty steel tray which also forms the base of the casing. The front panel is made from a custom aluminium extrusion and the rear panel is a single  massive casting which also acts as the heat sink for the output stages. The steel top plate slides into place and is therefore easily removed for quick access to the electronics and the loudspeaker fuses.
The solid wood and cheeks can be supplied in a larger size for stacking the SA200 with a C200 control unit. A rack mouting kit for professional use is also available.
The SA200 is ideally partnered by the C200 Control Unit although it is, of course, suitable for use with any other high quality audio pre-amplifier to form the heart of a system giving the very best performance.

Sensitivity:  1,0 V (reference 100W/8 Ω  at 1 kHz)
Input Impedance:  20 k Ω
Noise (unweighted or CCIR/ARMweighted reference 100W/8 Ω ):  less than -100 dB
Gain to Loudspeaker Terminals (29,0 dB at 1 kHz):  phase non-inverting
Loudspeakers : 4 - 16 Ω
Nominal Output level:  100 watts into 8 Ω
Power Output an Distortion
Both Channels into 8 Ω :  100 W at 0,08% Total Harmonic Distortion 20 Hz -20 kHz
at any level up to 100 W into 8 Ω , 1 kHz less 0,03% (typically 0,01%)
at any level up to 160 W into 4 Ω  , 1 kHz less than 0,05% (typically 0,02%)
Output Power at 1 kHz at clipping (0,1% Total Harmonic Distortion ) with both channels driven is typically 125 W per channel into 8 Ω  , 195 W per channel into 4 Ω
Frequency Response:
10 Hz - 20 kHz +0, -0,5 dB (It is recommended that the pre-amplifier's high frequency response be curtailed to at least -3 dB at 50 kHz
Power Supply:  240 V AC, 48-63 Hz, 600 VA maxcimum (the unit may be adjusted to work at 220 V or 120 V if required)
Dimensions (W x H x D):  464 x 95 x 350 mm (18-1/4" x 3-3/4" x 13-3/4")
Weight:  10,0 kg (22 lb)

JVC R-S55L receiver

FM Tuner Section
Tuning Range:  87,6 MHz - 108 MHz
Usable Sensitivity (IHF):  12,2 dBf (1,1 µV/ 75 Ω)
50 dB Quieting Sensitivity:
Mono :  15,9 dBf 91,7 µV/75 Ω)
Stereo :  38,2 dBf 922 µV/75 Ω)
Mono :  0,15%
Stereo :  0,30%
Signal-to-Noise ratio:
Mono :  78 dB ( A-Net weighted (72 dB DIN)
Stereo :  68 dB A-Net weighted (63 dB DIN)
Selectivity:  65 dB ±400 kHz (45 dB ±300 kHz, DIN)
Capture ratio:  1,0 dB
IF Rejection:  90 dB at 98 MHz
Image Rejection:  55 dB  at 98 MHz
Stereo Separation:  45 dB at 1 kHz
MW Tuner Section
Tuning Range:  525 kHz - 1605 kHz
Usable Sensitivity:  300 µV/m, 50 µV/m (external antenna)
Signal-to-Noise Ratio:  45 dB
Distortion:  0,5%
Selectivity:  46 dB ±9 kHz
LW Tuner Section (DIN)
Tuning Range:  150 kHz - 350 kHz
Usable Sensitivity:  40 µV
Signal-to-Noise Ratio:  45 dB
Distortion:  0,5%
Selectivity:  50 dB ±9 kHz
Amplifier Section
Power RMS (both channel driven, 20 Hz - 20 kHz):  40 watts per channel at 8 Ω
Power RMS (both channel driven at 1 kHz):
42 watts per channel at 8 Ω
50 watts per channel at 4 Ω
Total Harmonic Distortion:  0,03% at rated power (0,008% at half rated power, 1 kHz)
Signal-to-Noise Ratio (IHF short circuit A network):
Phono :  77 dB
Tape Play :  98 dB
Dimensions (W x H x D):  422 x 109 x 403 mm (16-5/8" x 4-1/4" x 15-7/8")
Weight:  8,3 kg (18,3 lbs)

JVC JR-S400 receiver

FM/AM Stereo Receiver with S.E.A. Graphic Equalizer
Though in size and looks it's the same as the higher-power JVC model, the JR-S400 has slightly less output power and a correspondingly lower price. Its solidly-built OCL power amplifier section delivers a comfortable 70 watts per channel, min. RMS, into 8 ohms, both channels driven, over a 20 Hz to 20 kHz range, with no more than 0,2% Total Harmonic Distortion. It has virtually the same fine FM?AM section and S.E.A. Graphic Equaliser as the JR-S600, though, and two Phono, two Tape and FM/AM/AUX source selection as well as two-system speaker selection and more.

Power Section
Good transient response and ample power reserve are assured with the pure complementary OCL power amp section, with an initial differential amp followed by a Class A predriver leading to a Darlington-connected parallel push-pull final stage.
Power Supply
A well-regulated transformer improves power response during high-amplitude musical passages, while reducing distortion and crosstalk in the subsonics. No power reserve dry-up is possible thanks to dual huge capacitors. JVC's patented Triple Power protection circuit is included.

Phono Equalizer
The PNP-NPN-PNP phono equalizer accepts up to 200 mV input with negligible distortion. The RIAA curve deviation is ±0,5 dB.

FM and AM Highlights
As in the JR-S600, the tuning capacitor in this precision FM section is the 4-gang, frequency linear type affording, in combination with a low-noise FET, greatly increased FM sensitivity. The up-tilted, super-long (200 mm) FM/AM dial high-inertia dual-flywheel design, a unique lateral-tune control and stretch-free "Radial Cord" cables in the tuning mechanism mean quick, dependable operation. Also as in the more expensive JR-S600, the FM selectivity is increased without harm to other specifications or sound quality by the use of a new 4-resonator single-unit ceramic filter, coupled with a 4-ploe phase-linear LC filter, in the FM IF section.

Other features:
Consstant-Voltage Dual Power Supply
Slider Controls - volume and balance
Push-button source selectors
Two-deck recording/dubbing - Monitor and record to both; dub (copy) from Deck1 to Deck2
FM Muting Off/Mono switch
Loudness High and Low filters
FM Det out Jack
One-touch / 2-system speaker terminals
Internal FM antenna switch
Two AC outlets and more

Output Power: 
70 watts per channel, min. RMS, at 8 Ω from 20Hz-20kHz, with no more than 0,2% T.H.D.
80 W per channel into 8 Ω (1 kHz T.H.D. 0,2%)
100 W per channel into 4 Ω (1 kHz, T.H.D. 0,2%)
Intermodulation Distortion:  0,3% at rated output
Damping Factor:  50 at 8 ohms
Load Impedance:
4 - 16 Ω per System 1 or 2
8 - 16 Ω per System 1 +2
Input Sensitivity/ Impedance:
Phono :  2,5 mV (50 k Ω)
Aux :  220 mV (70 k Ω)
Tape Play (PIN, DIN) :  220 mV (70 k Ω)
Signal-to-Noise ratio (IHF Short-Circuit A network):
Phono :  70 dB
Aux :  95 dB
Tape :  95 dB
Recording Output:
PIN :  180 mV
DIN :  30 mV ( 80 k Ω)
Phono Equalizer Deviation:  ±0,5 dB from RIAA Curve
Phono Overload :  200 mV (RMS), 560 mV (p-p)
S.E.A. center Frequencies:  40, 250, 1 j, 5 k , 15 kHz
S.E.A. Control Range:  ±12 dB
FM Tuner Section
Usable Sensitivity:  9,8 dBf (1,7 µV/ 300 Ω)
50 dB Quieting Sensitivity:
Mono :  16 dBf (3,5 µV/300 Ω)
Stereo :  36,8 dBf (38 µV /300 Ω)
Stereo Separation (at REC Out): 
50 dB  at 1 kHz
35 dB at 10 kHz
Distortion [Mono / Stereo]:
100 Hz :  0,1% / 0,25%
1 kHz :  0,1% / 0,25%
6 kHz :  0,25% / 0,4%
Signal-to-Noise Ratio (Max. 1000 µV input):
Mono :  72 dB
Stereo :  65 dB
Alternate Channel Selectivity:  80 dB
Capture Ratio:  1 dB
Image response ratio:  100 dB at 98 MHz
AM Suppression:  55 dB
FM DET Output:  100 mv (10 k Ω)
AM Tuner Section
300 µV/m (bar antenna)
30 µV (ex, antenna)
Signal-to-Noise ratio:  55 dB
Dimensions (W x H x D):  560 x 169 x 431 mm (22-1/16" x 6-11/16" x 17")
Weight:  18,5 kg (40,8 lbs)