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

Technics SL-1700

 Technics SL-1700 Direct Drive Semi-Automatic Turntable

The SL-1700 offers the famous Technics direct drive system with the added convenience of semi-automatic operation. Once the tonearm is manually positioned over the lead-in grooves, the automatic mechanism will lower the tonearm onto the record when the lever is flicked, and automatically return it to the arm rest at the complteion of play. The  unit is then automatically shut off. This handy feature frees the user from rushing to the turntable at the end of record play and also saves wear on your stylus.   At any time during play, flicking the stop lever will cause the tonearm to automatically lift up and return to the arm rest.
  To control the DC direct drive motor, the Sl-1700 incorporates a B.FG servo with One Chip IC which can perform the functions of up to 321 transistors, diodes and resistors. B.FG stands for Back-Electromotive-Force Frequency Generator and it desribes the method whereby the back electromotive force induced by the rotor in the stator coils is used to monitor the speed of the platter. The waveform obtained from this becomes the reference for the frequency generator. Its output is compared with the standard calibration frequency obtained from the reference oscillator and then, when needed, a correction signal instantly changes the motor drive current to the proper value to turn the platter at precisely the right speed. Wow & flutter for the SL-1700 is an insignificant 0,025% (WRMS), while rumble is -73 dB (DIN B).

 The SL-1700 also is equipped with Technics newly designed Floating Double Isolator, which prevents acoustic feedback by shielding the turntable and tonearm assembly from external vibrations. This isolator actually insulates the turntable from the outside with two layers of specially designed isolators constructed of metal springs and special vibration absorbing material.
 The SL-1700 is equipped with several other defences against acoustic feedback; a heavy zinc alloy tonearm base, a newly designed turntable mat, and a precision made diecast aluminum cabinet. The tonearm is gimbal suspended to achieve 7 mg friction. Effective arm mass has been kept very low (22 g) to accommodate premium high compliance cartridges.
Other features of the Sl-1700 include a fine-scale direct reading anti-skating control, illuminated stroboscope, independent pitch controls variable by up to 10%, viscous-damped cueing device, and detachable dust cover.
Specifications SL-1700
Turntable Section
Type:  Direct drive semi-automatic turntable
Motor:  Electronically controlled brushless DC motor
Turntable Platter:  Aluminum diecast , 330 mm (13") diameter
Turntable Speeds:  33-1/3 and 45 rpm
Speed Change Method:  Electronic change
Variable Pitch Controls:  Individual adjustment controls,  10% adjustment range
Wow and Flutter : 0,025% WRMS (JIS C5521) ±0,035% weighted, zero to peak (DIN 45507)
Rumble:  -50 dB (DIN 45539 A);  -73 dB (DIN 45539B)
Tonearm Section
Type:  Universal S-shaped tubular arm, static-balanced type, direct-reading tracking force adjustment, with anti-skating force control device, oil-damped cueing device
Effective Arm lenght:  230 mm (9-1/16")
Overhang:  15 mm (19/32")
Friction:  7 mg (horizontally and vertically)
Effective Mass:  22 g (6,0 g cartridge weight, 1,75 g stylus pressure)
Tracking Error Angle:  Within +3° (at the point of 14,5 cm or 5-45/64" record);  +1° (at the point of 5,5 cm or 3-2/16" from the centre)
Offset Angle:  21,5°
Adjustable Tracking Force:  0 - 3 g (direct-reading)
Cartridge Range:  5 - 11 g
Headshell Weight:  9,5 g
Power Supply:  AC 120 V - 240 V, 50/60 Hz
Power Consumption:  6 W
Dimensions (H x W x D):  125 x 453 x 369 mm ( 4-15/16" x 17-12/16" x 14-9/16")
Weight:  8,8 kg  (19,4 lb)

Technics Direct Drive Turntable Technology

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