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.

Specifications:
Inputs:
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
Outputs
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
Performance
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
Phase
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)


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