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 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.

Specifications
Inputs:
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
Outputs
Loudspeakers : 4 - 16 Ω
Nominal Output level:  100 watts into 8 Ω
Performance
Power Output an Distortion
Both Channels into 8 Ω :  100 W at 0,08% Total Harmonic Distortion 20 Hz -20 kHz
Distortion
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)


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