Technics SL 1100 AC Brochure

Page 2

SL-11OOAC

Direct-Drive Turntable

Technics by Panasonic offers a
revolutionary new development in
turntable technology. The

sophisticated, highly-praised direct

drive turntable-SL-1100AC.
Technics by Panasonic has

achieved the ultimate in mechanical

simplicity with only one moving

part-the combined motor/turntable

structure. The SL-l 100AC's 4.4 lb.
cast aluminum platter, 1 33-" in
diameter, is mounted directly on
the shaft of the motor. No stepped
shafts, idlers, or belts are used in
the system. And this explains why
the turntable rotates practically
without a trace of vibration, wow
or flutter. Because only a single
moving part is employed, wear is
practically nil, and the turntable
maintains its initial performance
just about indefinitely.

The SL-1100AC comes with a
matching high performance tone-
arm and impressive cast aluminum
base, weighing 26 lb. 4 oz. in total.
Stroboscope markings are molded
around the platter to precision
check the correct speed of rotation.
A strobe lamp is included. With

For Those Who Want
Professional Performance
at Moderate Cost

Cross Sectional View of DC Brushless Motor

Motor,vTurntaD|e Shaft

Position Detecting Corl l

Rotor Frame

,. 1|1' - i

1 fr *4

El u Speed
Control metry

and motor housing. When a motor
rotates at high speed, it transfers
vibrations, no matter how effective the
motor mounting may be in trying to
absorb it. This vibration is transmitted
through the turntable platter to the
record and the pickup stylus, which

passes it along with the music as a low-

the SL-1100AC you have added the pitched roar. Because the SL-1100AC

definitive component to your high-
fidelity system. Complete with

a deluxe plexiglass dust cover.
CSA approved.

Direct-Drive System

The heart of this unique record
playback system is an ultra-low speed
DC brushless motor that rotates at
exactly the same speed as the records
you're playing-33:} or 45 rpm. Thus,
Technics by Panasonic has done
away with turntable parts that create
trouble in performance and in
servicing. Parts like belts and idler
wheels, which deteriorate over the
years, making it difficult to maintain
the initial performance charac-
teristics of even the best conven»
tional turntable. And parts like con-
ventional AC motors, with their built-
in hum problem.

Rumble, another problem of the
conventional turntable, is practically
non-existent. Its usually caused by
vibration of the motor. transmitted to
the turntable through the drive system

motor rotates exactly at the speed of the

records you're playing, there's barely a
trace of the vibration produced by high-
speed motors-hence, virtually no
rumble. In fact, the rumble of the
SL-1100AC is in excess of -65dB (DIN
A), -70 dB (DIN 8). Hum, always a
problem with AC motors and power
lines, has been eliminated by use of
the DC brushless motor. AC motors
have magnetic flux leakage, while
ordinary DC motors using a brush and
commutator create their own brand of
electrical noise caused by sparking.

Multi-Pole DC Brushless Motor
The multi-pole DC brushless motor is
fed by an internal adaptor which
converts ordinary 60 Hz AC current to
20 V DC. A built-in electronic analogue
feedback speed control system main-
tains exactly the proper speed you've
selected. A 50 kHz signal is fed into
the first coil of each of the three pairs
of control signal pickup coils wound
in the stator. The control rotor, a
toothed wheel rotating with the motor

ArmaturefStator Core)

l)

Magnet Rotor
Armature($tator Coal)

Posntron Detecting Rotor

rotor. varies the coupling of the pair of
coils to produce changes in the output
voltage of the second coil of each
pickup coil. The outputs from three
pairs of control signal pickup coils are
then fed back into the electronic circuit
to keep the rotation of the motor constant.
Neither the frequency nor fluctuation
in the voltage of AC mains influences
the rotation of the motor-an important
feature when one considers the ever
increasing brownouts and voltage
fluctuations caused by commercial
power suppliers.

The SL-1100AC starts immediately
because the DC motor and the exclusive
Technics by Panasonic barium-ferrite
permanent magnet employed in the
rotor have high magnetic flux density.
which means high starting torque, or
reaching playing speed much faster
than conventionally-designed
turntables-within one-half revolution
at 33g, rpm, in fact. And because of its
high torque, rotation won't stop even
if you press your dust cleaner

onto a record hard to wipe off dust.

At the same time, though, power
consumption is extremely small-only
4.0 watts (DC motor itself consumes
only 0.1 watt).

As the machine does not employ

belts nor idler wheels. it suffers no
damage even if you stop the turntable
with your hand while it's on. The
SL-1100AC is, therefore, tamper-proof.