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





Pioneer SA-900 amplifier

Model SA-900 is an professional-type all silicon solid state pre/main stereo amplifier.

The SA-900 is one of Pioneer's most advanced amplifiers. It contains professional features nestly compacted into an all solid state set that's ideal for use with high performance stereo systems. It presents a powerful 200 watt integrated amplifier of exceptional flexibility. Only the finest and most expensive materials have been used throughout, from the low noise silicon transistors in the MC and front end sections to the special Brazilian rosewood tipping the front panel. The control amplifier has FET end advanced 3-stage E-S (Emitter-Source) feedback circuitry. The pre and main amplifiers can be used independently and there are inputs for a wide variety of cartridges and 2 sets of speaker terminals.

 


Features

Preamplifier is composed of three precision made sections.

MC Section: using very special low-noise transistors, this section adequately amplifies low output moving coil cartridges. Has very low noise level.

Front-end Section: uses low-noise silicon transistors and a direct coupled 3-stage E-E feedback circuit, resulting in significantly better frequency response, a decrease in harmonic distorion and improved tonal quality.

Control Amplifier Section: features FET and a direct-couples 3-stages E-S feedback circuit. Gives a high S/N ratio, and minimal distortion.

Truly Precise Tone Controls

Despite their markings, most sets have controls  that are very approximate. In fact, they are not usually flat even when set at flat. The SA-900 is radically different. Set its tone controls at flat, and the signal really comes out flat. Accurate 3 dB step controls for individual bass and treble adjustment.

Power-Packed main Amplifier

This superior main amplifier puts out a full 145  watts at 8 ohms with distortion under 0,5% (IHF music power). That is more than enough to fill a concert hall. Damping factor is better than 67 at 8 ohms. Silicon varistor is used for temperature compensation and stable performance at all times.

Independent use of Pre and Main Amplifier

A selector switch on the rear panel allows independent use of pre and main amps, desirable for multi-channel systems. The preamplifier is designed to be used as a control amplifier.

Exceptional Flexibility -  unusual Range of Inputs and Outputs

The SA-900 features, for example, two phono inputs. By means of push-button selection, one input accomodates either a high output MM type cartridge or a low output MC cartridge. Naturally  there's tape monitor for Tape/Source comparsion, and  there are also two sets of speaker outputs.

A Host of Audio Refinements

A few Pioneer extras include Hi and Low filters, and a special muting switch of -20 dB. And the SA-900 can also be used as a channel amplifier by setting the channel filter between pre and main amplifier sections.

 


Specifications

Audio Section

Circuitry:  Quasi-complementary single ended push-pull

Music Power Output:

200 Watts at 4  (distirtion below 0,3% at 1 kHz/IHF)

145 Watts at 8  (distortion below 0,3% at 1 kHz/IHF)

Continuous Power Output:

84 W / 84 W at 4  (distortion below 0,3% at 1 kHz)

60 W / 60 W at 8  (distortion below 0,3% at 1 kHz)

Continuous Power Output  (both Channels driven)

64 W + 64 W at 4  (distortion below 0,3% at 1 kHz)

50 W + 50 W at 8  (distortion below 0,3% at 1 kHz)

Total Harmonic Distortion: less than 0,08% ( 45 W at 1 kHz)

Frequency Response:  20 Hz to 50 kHz ±1 dB

Power Bandwidth:  20 Hz to 50 kHz (distortion below 0,3% constant/IHF)

Signal-to-Noise Ratio: 

Phono :  better than 85 dB

Aux :  better than 95 dB (volume, maximum, tone flat, at the rated output/IHF)

Inputs Sensitivity/Impedance (at 1 kHz)

Phono MM :  3,1 mV/ 50 k  

Phono MC :  0,155 mV/ 150 k  

Phono CER :  71 mV/ 100 k  

MIC :  1,9 mV /50 k  

Tuner :  180 mV / 200 k  

Tape Monitor :  180 mV / 200 k  

Tape head :  1,8 mV / 150 k  

Aux :  180 mV / 200 k

Main-In :  500 mV / 100 k   

Damping Factor:  better than 67 at 8  (at 1 kHz)

Output Terminals and Jacks

Speakers :  4 to 16

Stereo Headphones Jack, Pre-Out :  3 V

Simultaneous Tape Recording :  180 mV

Tape Recording/playback Jack :  DIN standard

Center Channel Output :  500 mV

Equalization Curves: 

Phono ;  NFB type RIAA,

Tape :  NFB type NAB

Tone Controls (3 dB step)

Bass :  -9 dB to +12 dB at 100 Hz

Treble :  -12 dB to +9 dB at 10 kHz

Filters: 

Low :  -6 dB ( 12 dB/oct) at 50 Hz

High :  -6 dB  (12 dB/oct) at 10 kHz

Loudness Contour:  Switchable to On-Off

+14 dB at 50 Hz

+7 dB at 10 kHz

Residual Noise:  less than 0,8 mV at 8  (volume, mninmum, tone flat)

Muting :  -20 dB (switchable On/Off)

Crosstalk (1 kHz):

Aux :  less than -50 dB

Phono :   less than -48 dB

Power Supply:  Bridge rectifier using silicon diodes

Power Requirements:  110, 117, 130, 220, 240 Volts (switchable) 50/60 Hz AC

Power Consumption:  250 VA (max)

Dimensions (W x H x D):  405 x 140 x 339 mm (1-15/16" x 5-1/2" x 13-11/32")

Weight (Net):  12,3 kg  (27 lbs)

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