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





Philips AF 829 turntable


Philips model AF829 turntable is front operated, direct control, and fully automated. Direct control is a new system combining the advantages of measuring the actual speed at the turntable and the well-known advantages of belt drive, in combination with the subchassis  principle used in earlier Philips turntables. The major achievement, according tp Philips, is that it brings the specifications to the level of direct drive, but without the inherent problems of direct drive which requires extremely fine construction to avoid rumble, suppress microphony, and decrease sensitivity to shocks. Direct control begins rotating the motor at 33 or 45 RPM, as selected. The belt transfers the rotation to the turntable. The speed of the turntable is continuously sensed by the tacho-generator and converted into a voltage, the output of which is fed into the control unit where this voltage is compared to a reference voltage. The resulting difference voltage is used as a control signal to adjust motor speed. Thus in this system all extrnal influences are compensated, including changes in tracking force, different record weights, use of a dust bug, changes in environmental temperatures and relative humidity, mains voltage, and frequency fluctuations. 
features:
free-floating sub-chassis
low torsion tone-arms
tachometer
speed regulation
CMOS memories
Specifications
System:  Direct Control
Operations:  Full-automatc
Speeds:  3-1/3 and 45 rpm
Turntable Diameter:  310 mm
Wow and Flutter : less than 0,025 (WRMS)
Rumble:  less than 73 dB (DIN B)
Tonearm Type:  Linear
Tonearm length:  215 mm
Tracking Error:  less than 0°9' /cm
Dimensions (W x H x D):  450 x 141 x 365 mm


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