Technics QUARTZ SP-15 - Page 4

m FEATURES
Quartz synthesizer system that for the first time in
the world has made it possible to achieve a digital
pitch control of +9.9% in 0.1% increments
In conventional quartz players the quartz reference was in
effect only within strictly limited ranges: whenever vernier
speed change was required, the quartz circuit had to be
switched off. In the Technics SP-15, we took the lead by
locking the quartz, thus making it possible to effect a high
degree of pitch control accuracy over a range as wide as
+9.9% in 0.1% increments, which is below the threshold of
human perception.
Moreover, the pitch control, coupled with the clear digital
indicator, enables you to accurately and precisely tune with
musical instruments, vary pitch slightly for obtaining a
musical note from a record or alter tones by a half-note.
Oversized turntable that cuts off and absorbs
external vibrations.
Based on analyses of the turntable vibration modes and
vibrations in the sound range, a special viscoelastic material
is applied to the reverse surface of the turntable platter for
deadening.
The deadening material is applied to the undersurface and
outer periphery of the turntable platter, with the rubber
turntable mat on the surface settled into the turntable
platter. This design is superior in acoustic characteristics
even at high sound levels through elimination of turntable
resonance and absorption of external vibration.
Moreover, the oversized aluminum die-cast turntable
platter, 33.9cm (13-11/32"') in diameter, is heavy with
2.7 kg (5.9 |b.) of its own weight, with a moment of inertia
of 380 kg cm? (130 Ib. in?) for large heavy weight class
design.
Vibration damping structure by the precision
aluminum die-cast cabinet and TNRC.
The acoustical characteristics of the player system are
inevitably affected by the turntable platter and cabinet
employed. The SP-15 adopts an aluminum die-cast cabinet
superior in strength, with high processing accuracy, and the
new acoustic material TNRC excellent in acoustical
properties. Through cutting-off and absorption of external
vibrations, the unit is designed for improved acoustic
characteristics, with susceptibility to feedback minimized.
Electronic circuits of more than 3,000 discrete
elements concentrated into 41Cs
The 4 kinds of IC, i.e., Synthesizer pitch control CMOS LSI
(MN 6042), Frequency dividing IC employing I7L, ECL
m@ RUBRICATION
Apply 2 or 3 drops of oil once after every 2000 hours of
operation. (See Fig. 13.)
This time interval is much longer than that of conventional
type motors (200—500 hours).
Please purchase original brand of oil (Parts number is SFWO
010.)
a]
(DN 860), phase speed control IC (AN 660) and Driving IC
(AN 640) into which high density electronic circuits of
more than 3,000 discrete elements have been compressed
have made it possible to produce this high precision quartz
turntable.
Quartz Controlled Rotation Accuracy
The SP-15 utilizes the oscillation of a quartz crystal as a
reference signal or source. This oscillation is not affected
by temperature change or power fluctuations. By
synchronizing the rotation of the turntable platter
accurately to the reference signal, speed drift of the unit is
held within 0.002%.
Technics’ unique motor construction in which the
rotor of the motor is integrally formed with the
turntable
High torque motor of 3kg-cm with starting time
of 0.4 second is capable of instant speed
change-over (at 33-1/3 rpm.).
With the double braking system of the electronic
brake and mechanical brake, the turntable stops
instantly (0.4 second) upon depression of the start
« stop button (at 33-1/3 rpm.)
High performance with wow and flutter of only
0.025% (JIS C5521) and rumble of —78 dB (IEC
98A Weighted).
Pitch lock mechanism capable of locking the speed
selection and pitch control operation
Malfunction caused by accidental touching of the operating
portion during playing, can be prevented.
Highly efficient pulse power supply circuit is
employed for the DC power source
Since DC voltage is obtained by oscillating high frequency
(20 kHz) through direct rectification of AC power supply
for voltage conversion at the pulse transformer, there is no
leakage of the commercial power source frequency.
Stable and positive mechanism that can stand
frequent use for business use, etc. and a switch
section with point contacts.
Revolutions at 3 speeds of 33-1/3, 45 and 78.26 rpm. are
employed, taking into account business use.