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