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





Pioneer PL-540 turntable

 

Auto-Return Quartz-PLL DC Direct-Drive Turntable

Now that you know to look for in a turntable, look at the PL-540 from Pioneer. If you've ever owned a good manual single-play turntable without automatic return, you know how desirable the latter can be - if only it doesn't compromise tone arm sensitivity.

The auto-return system in the Pl-540 doesn't harm sensitivity. If you've ever wished your turntable had the accuracy of a professional studio type - but without a studio-standard high price. The DC Hall motor and Quartz -PLL in the PL-540 deliver the same accuracy - 0,025% or less wow and fluter - as monitor turntables used in record-cutting studios. But its price is considerably less. If you've suspected that the boxy cabinet and shaky little feel on yesterday's best turntable are not  enough to be called "best" today, and if the latest improvements in tone arm suspension and platter design have set you thinking about replacing your favorite noisy old faithful; look at the Pioneer Pl-540.  And as you do, remember to ask for an audition of its superb tonal quality. Your ears will see that it's the turntable you've been listening for.

 


Our Own Quartz-PLL Servosystem

There are 200 evenly-spaced magnetic "bits" on the bottom of the rotor of the DC motor, and each has two poles; the north pole of one is opposite the south pole of the next, and so on. Then positioned below is a circular circuit board on which is a printed coil with 200 poles. A current proportional to the actual speed of the direct-drive motor is generated in the coil circuit as the magnets rotate above, and that current is sent to the PLL or Phase-Locked Loop circuit and Sampling & Hold Circuit in the servo. There phase is compared with that of an ultra-accurate reference signal from the built-in Quartz oscillator. Differences in phase if any, are converted into control voltages which in turn "tell" the motor to speed up  or slow down to achieve absolutely accurate rotational accuracy in far less time than it takes your eye or ear even to begin to detect even the slightest error.

 


Specifications

Drive System:  Quartz PLL direct-drive system

Motor:  Quartz PLL Hall-motor

Speeds:  33-⅓ and 45 rpm

Wow and Flutter:  no more than 0,025% (WRMS)

Signal-to-Noise Ratio:  more than 73 dB (DIN-B)

Tone Arm

Type:  Static-balanced S-shaped pipe arm

Effective Arm Length:  221 mm (8-11/16")

Overhang:  15,5 mm (5/8")

Usable Cartridge Wight:  4 g - 10 g

Power Requirements:  110/ 120/ 220/ 240 V 50/60 Hz

Power Consumption:  8 watts

Dimensions (W x H x D):  440 x 145 x 365 mm (17-5/16" x 5-11/16" x 14-3/8")

Weight:  10 kg (22 lb 1 oz)

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