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





Aiwa AP-D50 turntable

Direct-Drive Turntable

A completely new concept in hi-fi component design; the world's first automatic front-loading turntable. Whether you're aiming for convenience or performance, the ingenuity of the AP-D50 is hard to beat.

 

Operation

First set the speed and record size. Then after placing the disc on the loading tray, press the Play/Cut button and the disc is loaded into playing position by the motorized mechanism. Another touch of the Play button and the arm is transported over the record and play begins. As a safety device returns the arm to the armrest before permitting the loading tray to come out, the Eject button may be pressed either during play or after play has completed.

 

High performance direct-drive motor

For accurate rotation speed completely free from cogging or other undesirable effects, the AP-D50 employs a 4-phase 8 -pole linear torque motor with a frequency generator type speed detector. This compares the motor rotation speed to a standard rotation frequency and makes needed connections virtually instantaneously. A heavy 1,3 kg aluminum diecast platter contributes to the very low 0,028% (WRMS) wow and flutter, and rumble, another result of improved motor design, is a superb 75 dB (DIN-B).

 

Low resonance concrete resin sheet material

Even if a turntable chassis material has a high degree of resistance to acoustical feedback, its effectiveness can be drastically lowered by overlooking the section of the platter which actually contacts the record itself, the rubber mat. At the AP-D50's turntable sheet is a part of the auto-loading mechanism, Aiwa engineers were able to take advantage of the need for rigidity to develop a new material. This "concrete resin", a formulation of CaCO₃ and glass fiber in a polyester base, is able to offer superior resistance to low frequency resonance, enabling the AP-D50 to absorb larger doses of acoustical feedback with no detrimental effects on tone quality.

 

Adjustable Pitch Control

When singing or playing along with a musical instrument, some variation in playback speed may be desired to raise or lower the record's pitch. The pitch control knobs on the AP-D50 enables the unit's speed to be varied by as much as ±3%. The 4 rows or stroboscopic speed indicators at the platter edge are useful in setting speed to precisely 33 or 45 rpm.

 


Full manual operation

It's difficult to conceive of a turntable which can be operated manually without raising the dust cover, but the AP-D50 can do just that. An arm carrier lever located on the front panel permits manual, positioning or the arm when raise off the record surface. Naturally, hydraulic arm cueing is controllable from the front panel in both manual and auto modes of play.

 

Photoelectric auto return mechanism

Most turntables employ a mechanical device which activates auto return operation by detecting a buildup of stress on the arm; this stress unfortunately has the side effect of increasing distortion. The AP-D50 employs a sophisticated non-contact photoelectric system coupled to the arm's own motor, thus assuring uncompromised high performance.

 

Sensitive J-shaped arm with removable headshell

Designed for accurate tracking in the record groove with minimal tracking error and distortion, the low mass aluminum pipe arm takes a universal headshell for easy cartridge conversion. A high compliance MM cartridge with diamond stylus is included as standard equipment.

 

Repeat operation

With this button pressed in, record play will be repeated continuously until halted manually. An LED indicator has been provided to show that the repeat switch is set to on.

 

Exclusive rec-sync feature

When connected by cable supplied with most Aiwa cassette deck and portable stereo models, disc-to-cassette dubbing will commence automatically with the lowering of the AP-D50's arm on the record. Ask for a demonstration of this convenient feature at your Aiwa dealer's showroom

 


Specifications

Drive System:  FG Direct-drive system

Motors: 

1 x 4-phase 8-pole linear torque DD hall motor

2 x DC motor

Turntable Platter:  Aluminum alloy diecast

Diameter:  300 mm

Weight:  1,3 kg

Moment of Inertia:  220 kg/cm² (with turntable sheet)

Speeds:  33-⅓ and 45 rpm

Wow and Flutter:  0,028% (WRMS)

Signal-to-Noise Ratio:  75 dB (DIN-B)

Tonearm Type:  Static balanced type

Effective Arm Length:  215 mm

Overhang:  15 mm

Usable Cartridge Weight:  3,5 - 8,5 g

Maximum Weight:  18,5 g (with headshell)

Cartridge Type:  Moving magnet type

Frequency Response:  20 - 20,000 Hz

Output Voltage:  2,5 mV

Stylus Pressure:  2,5 g

Dimensions (W x H x D):  450 x 106,5 x 375 mm (17-3/4" x 4-3/16" x 14-13/16")

Weight:  7,2 kg (15,9 lbs)


 

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