...převzatý text ze "stereonomono"
Automatic Hi-Fi Stereo Turntable with Direct Drive
Featuring:
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 33⅓ 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
Horizonta
