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 SP-10 MkII

 Technics  SP-10 MkII Quartz-Controlled Direct Drive Turntable
Represents a standard of accuracy and quality in disc reproduction that has never been attained before. This truly outstanding three speed package unquestionably constitutes a new reference against which professinal systems will have to be measured for years to come. Just glance at some of these amazing features; almost total absence of speed drift; immeasurably small wow & flutter; extreme quietness; enormously high torque, and practically instantaneous starting and stopping.
 The SP-10 MkII employs a sophisticated electronic sevo control circuit to deliver expressed mathematically, rotational speed accuracy. Speed drift remains within ±0,002%. During  the 30 minute playing time of the average LP side, this amounts to a maximum of ±0,036 seconds error. This makes the rotational speed independent of AC power line fluctuation and the passage of time.
The secret behind  this amazing speed control is the is the ingeneous quartz oscillator which produces an unvarying reference frequency to which the motor and the strobe light are locked. The quartz reference frequency is split by a frequency divider into appropriate control frequencies for each of the 3 speeds. Then the frequency generator translates platter RPM into a signal which is fed nto the phase control and speed control circuits which then alter the motor voltage by just the right amount to maintain the correct speed in response to changing load conditions.
This corrective current, by being phase locked to the reference frequency, permits instant corrective torque response when needed. The overall result of this circuitry shows up very impressively in two of the most revealing measurements of turnyable quality. Wow & flutter are a low, low 0,025% (WRMS) while rumble is -73 dB (DIN B).

 Another exclusive feature of this state-of-the-art. Instrument is its extremely high torque of 6 kg-cm (5,2 lb-in) higher than that found in any other turntable. This means that rated speed will be maintained even under the most severe conditions of external drag. No longer will you hear a speed change when placing a disc preener on the record or even when accidentally brushing against the rotating platter. At 33 rpm, the rated speed of the Sp-10 MkII is reached within 0,25 seconds. This compares with the one second built-up time considered satisfactory in professional broadcast equipment.

Looked at another way, standard speed is reached after only a 25 degree turn of the platter. This short build-up time is achieved without sacrifice to the platter weight, which is a heavy 2,9 kg (6,4 lb). Not only does the Sp-10 MkII have a short build-up time, but it also is able to stop almost instantly. From the moment the stop button is pushed until the turntable stops requires only 0,3 seconds, which facilitates rapid speed changes. And whenever the platter is not running, the mechanical braking system holds the platter still.
 For extra operating convenience, stop and start functions may be controlled from a remote control unit which comes wirh the SP-10 MkII.
The power supply, housed in a separate cabinet, isolates the transformer from the electronics of the turntable and also permits a slim, elegant appearance for the SP-10 MkII. Other features include modular circuit construction for ease of servicing and a specially designed rubber mat on the under-side of the platter for vibration damping.
Specifications SL-10 MkII
Turntable Section
Type:  Direct drive turntable
Motor:  Electronic rectification, quartz-controlled phase-locked servo circuit, brushless DC motor
Turntable Platter:  Aluminum diecast
Diameter:  320 mm (12-19/32")
Weight:  2,9 kg (6,4 lb
Moment of Inertia:  380 kg/cm²  (130 lb/in²)
Turntable Speeds:  33,  45 and 78 rpm
Starting Torque:  6 kg/cm  (5,2 lb/in)
Build-in Time:  0,25 sec (=25° rotation) to 33 rpm
Braking Time:  0,3 sec (=30°rotation) from 33 rpm to standstill
Soeed fluctuation by load changes:  0% within 5 kg/cm  (4,3 lb/in)
Speed Drift:  Within ±0,002%
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)
Power Supply:  AC 120 V - 240 V, 50/60 Hz
Power Consumption:  20 W
Dimensions (H x W x D):  102,5 x 368,5 x 368,5 mm ( 4-1/64" x 14-31/64" x 14-31/64")
Weight:  9,5 kg  (20,9 lb)

Technics Direct Drive Turntable Technology

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