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 777

 Automatic Hi-Fi Stereo Turntable with Direct Drive
Shock-proof free-floating sub-chassis
Straight tubular-aluminiumtonearm with de-coupled adjustable counterweight
Very low-friction tonearm bearings
Light detachable headshell
Automatic diameter selection and positioning of arm on start of record.
Automatic stop, arm lift and return at end of record.
Hydraulically damped arm lift
Anti-skating adjustment for spherical and elliptical styli
Direct readout of stylus force.
Controls for 33 and 45 rpm, Start and Stop.
Pitch controls with 3-LED-bar actual speed indication
Attractive tinted dust cover with friction hinges.
 The AF777 has a high standard of performance. Rumble, for example, is better than -65 dB (DIN B), and wow and flutter is less than 0,05% (weighted rms).These very good figures are attributable to the thorough design and construction of the various sub-sections of the turntable; the suspension, tonearm, headshell, and especially the Direct Control electronics which regulate so precisely the speed of the turntable.

To ensure that the record always rotates at exactly the right speed, the rate of rotation of the turntable itself is continuously monitored and regulated by the Direct Control electronics. The turntable, which is belt-driven from a separate Dc motor, has a tachometer built into it. The output of the tachometer is accurately converted into a d.c. voltage whose level is proportional to the actual speed of the turntable. This signal is continuously compared with a stable d.c. reference signal. If anything tends to alter thr turntable speed the tacho-derived signal will differ from the reference; this difference causes the Direct Control electronics to immediately accelerate or slow down the drive motor sa as to correct the speed of the turntable.

In addition to improving rumble, wow and flutter and drift specifications, direct control of the turntable speed has the important advantage that the record speed is unaffected by external influences such as the drag ofa cleaning device or different stylus force. Similarly, the Direct Control electronics compensate for fluctuations in temperature or line voltage and frequency.
Top Quality Tonearm
The straigh tubular-aluminium construction of the tonearm gives it an ideal combination of lightness, strength and rigidity, mechanical properties sa vital to a top quality tonearm. Because it is straight, with the stylus on its longitudinal axis, and since the aluminium headshell is so liht, the tonearm's centre-of-gravity lies very close to its axis. Consequently, torsional forces on the arm are minimal. This helps to eliminate unwanted high frequency resonances and keeps the natural resonance of the arm, with the cartridge, to an acceptable low frequency.De-coupling of the tonearm's counteweight provides wideband damping.

Low Friction Bearings
Horizontal and vertical friction forces in the bearings have been reduced to an exceptionally low value (better than 15 mg), so that there is almost no resistance to movement of the arm. As a result, the stylus is aable to faithfully follow even the most delicate modulations in the record groove.
 Minimal Tracking Error
Geometric characteristics of the tonearm, such as offset angle and location of the stylus on the tonearm's axis, have been designed to minimise tracking error (better than 0°9'/cm)

Excellent Trackability
The exceptionally small tracking error, combined with very low bearing friction, ensures the excellent trackability characteristics of the tonearm. This is one tonearm which allows full advantege of the trackability of the chosen cartridge.

Free-floating Sub-chassis
The turntable and tonearm assemblies  are mounted on a separate sub-chassis which is suspended from the main chassis via three nickel-chromium leafsprings with butyl-ruber dampers. This free-floating sub-chassis type of suspension is a wellprvoen and extremely effective technique that achieves superb mechanical isolation of  the turntable and tonearm from the main chassis.

Rumble-free, shock-proof and protects record and stylus
The mechanical isolation of the turntable and tonearm has been further improved by careful lacation of the springs and by using material with the best possible damping properties. Suspension of teh motor from the main chassis has also helped improve isolation. The result is that rumble from the motor is virtually eliminated, and external disturbances, such as vibration and acoustical feedback are not transferred to the cartridge. Even quiete violent knocks to the outer casing will not cause unwanted acoustical noises. And, the valuable stylus and records are better protected from accidental damege.

Turntable Speeds:  33 and 45 rpm
Wow & Flutter:  better than 0,08% DIN ( better than 0,05% weighted rms)
Rumble: better than -43 dB (DIN A); better than -65 dB (DIN B)
Pitch Control Range:  ±3%
Speed Indication:  3-element LED-bar
Tonearm Type:  Tubular-aluminium
Tracking Error:  Better than 0°9'/cm
Bearing Friction:  Better than 15 mg, vertically and horizontally
Resonant Frequency:  10 Hz (with test cartridge)
Effective Arm Length:  215 mm (8½ inches)
Effective Moving Mass:  16,5 g
Anti-skating Adjustment:  For spherical and elliptical styli
Cueing Lever:  Hydraulically damped
Headshell:  Die-cast aluminium
Stylus Force: 
Range : 0 -3 gf
Indication:direct readout
Material : aluminium
Diameter : 320 mm approx.
Power Supply:  110 V, 60 Hz ; 220 -240 V 50/60 Hz
Current Consumption:  0,1 amperes
Dimensions (W x H x D): 
Dust cover closed : 420 x 141 x 348 mm (16½" x 5½" x 13¾")
Dust Cover Open : 420 x 335 x 385 mm
Weight:  5,8 kg (12,8 lbs)

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