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





DENON DP-2000


Servo Controlled Direct Drive Turntable with Quartz Control

The Denon DP-2000 was available as a motor unit only, with a plinth and static balance type tonearm (DP-2500), with a large plinth and no tonearm (DP-2550) or with a heavy-weight marble composite plinth (DP-2800).

The DP-2000 is not equipped with variable speed system but only with quartz lock system. The circuits of quartz oscillation, frequency divider, sampling hold and strobo-flash are same as that of the DP-6000. Start/Stop circuit, brake control circuit and motor driving system are noticeably different from that of the DP-6000. The motor driving system controls the motor by means of modulating the amplitude of commercial power source 75V (AC) in the same way as DP-3000.

CIRCUIT SYSTEMS OF DP-2000:
- Frequency Dividing
- Sampling Hold
- Play/Stop Memory
- Brake Time Setting
- Motor Driving System
- Comparsion and Brake Control
- 33/45 Time Constant Change-Over
- Head Amplifier and Pulse Shaping- Delay
FREQUENCY DIVIDING CIRCUIT

 The frequency of oscilation by quartz is 33.75 KHz and itis divided to 1/3, 1/9 and 1/9 when the table turns at rotation speed of 33 r.p.m. The frequency, demultipled to 138.8 Hz is added to the sampling hold circuit. In case of the rotation speed of 45 r.p.m. the frequency is divided to 1/2, 1/10 and 1/9 and the frequency is demultipled to 187.5 Hz In addition as frequency for strobo-flash, these frequencies are further divided to 1/2, and they are 69.44 Hz and 93.75 Hz for 33 r.p.m. and 45 r.p.m. respectively.

Specifications
Drive system: Direct drive by AC servo motor
Speed control: Frequency detection servo motor phase locked to a quartz crystal oscillator
Speed: 33.33 and 45rpm
Speed selection: Slide switch
Wow and flutter: Less than 0.015% WRMS
S/N ratio: Over 75dB (DIN-B rated)
Starting time: Less than 1.5 seconds
Absolute speed accuracy: Over 99.998%

Turntable platter: Aluminium alloy diecast, 30cm diameter


DENON DP-2500

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