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

Dual 1212

Motor and drive:
The turntable platter and change mechanism are driven by a vibration-free, four-ploe motor with an extremely low stray magnetic field.
Motor speed is constant for line-voltage variations of +_10%. It is dependent on (an dproportional to) line frequency. Two interchangeable motor pulleys are available for adaapting the changer to 50 or 60 Hz operation.
The motor pulley is fastened to the motor shaft by a set screw. When you change pulleys, be sure that the new pulley is set at the correct heoght.
The turntable platter is driven by the idler wheel,, which to prevent damage to its friction surfaces, is automatically disengaged when the unit is shut off. Setting the turntable speed to 33-1/3 , 45 or 78 rpm is done by raising or lowering the idler to bear against the proper step of the motor pulley.

Powerful Constant-Speed Hi-Torque Motor
Of entirely new design, the Dual's powerful and utterly quiet Hi-Torque motor effortlessly brings the heavy turntable to full speed virtually instantaneously. The rotor is dynamically balanced in both planes. Together with the evenly and precisely distributed poles, this eliminates at the source, one of the major sources of rumble and assures speed constancy.
All three speed are accurate within 0,1% with one to ten records. Further voltage variations can exced ±10% with no effect on speed whatever. Thus the Hi-Torque motor combines the advantages of the induction and synchronous motors.

Acoustic Feedback Eliminated
The only vibrations induced upon the stylus should be those originating from the recorded grooves. Any others, such as those present in the speakers, must be isolated from the stylus, or it will repeatedly transmit those spurious signals throughout the system - as "acoustic feed-back".
Dual has taken extraordinary care in eliminating anything that would tend to induce acoustic feedback. For example, the spring-mounted footings are internally cushioned with rubber between springs and caps. Further, the springs themselves are "soft", because the feathertouch side-to-side action of the operating slide switches do not require stiff vertical resistance.
And the motor, is thoroughly insulated against both shock and vibration. These are some of the "inside" reasons by you will find Dual automatic turntables in the highest quality single-cabinet consoles that can reproduce the full frequency response range without concern for acoustic feedback.

Drive System:  Idler Drive
Drive:  four-pole, single-phase, induction motor
Turntable Speeds:  33-1/3 , 45 and 78 rpm
Speed Adjustment:  adjustment range of 1 semitone(6%) at all three turntable speeds
Turntable:  non-magnetic, 4 lbs, hi-fi turntable
Wow and Flutter:  less than ±0,12%
Rumble:  less than 38 dB below signal level
Signal-to-Noise Ratio:  less than 56 dB below signal level
Tonearm:  balanced on all three axes; extremely low mass, and precision, friction-free suspension (vertical 0,01 g and horizontal friction bearing, friction less than 0,04 g)
Cartridge Holder:  removable, suitable for acceptance of cartridges having 1/2" mounting and possessing a weight of 1 - 8 grammes
Current:  alternating, 50 or 60 Hz, with appropriate motor pulleys
Line Voltage:  selector for 110 V or 220 volts
Power Consumptions:  7,2 watts approx. at 220 V, 50 hz
Current Requirements:  60 ma. Maximum at 220 V, 50 Hz; 95 ma. Maximum at 117 V, 60 Hz
Dimensions (W x H x D):
Weight:  10,6 lbs (without packing)

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