Dual 1019 - Acoustic Feedback Eliminated; Powerful, Constant Speed Continuous-Pole Motor; Eliminating Acoustic Feedback

The perfect balance of the turntable platter wis
painstakingly anrived at by the precisely calculated
addinon of molten metal into the specially drilled
wells around the bottom rim, (Fig. 20), Twelve
wells are provided for this purpose, although only
two or three are usually used,
The metal wed in the turntable is a non-ferrous
alloy, and thus offers no powshility of magnetic
inferaction with the cartridge
Concave Mat Surface
Here's anmher fine point thal's easy to overlook
of ahown in Pig. 21, the center of the ribbed mat
ii lower than the outer rim. This is to provide the
record with support around its widest circumfer
ence, especially important in preventing warped
records from slipping.
The mat iteelf is anti-alatic, and reduces the amount
of static electricity in the record.
POWERFUL, CONSTANT SPEED
CONTINUOUS-POLE'’™ MOTOR
Of entirely new design, the Dual’s powerful and
utterly quiet Continucin-Pole™ high torque motor
effortlessly brings the heavy turntable to full speed
virtually instantaneously, The roter is dynamically
balanced in both planes, Together with the evenly
and precisely distributed poles, this eliminates al
the source, one of the major sources of rumble and
assures apecd constancy.
All four speeds are accurate within 0.1%, with one
to ten records, Further, voliage Variations can ¢x-
ceed > 10% with no effect on speed whatever!
Thus the Continuous-Pole motor combines the ad-
vantages of the induction and synchronous motors
ACOUSTIC FEEDBACK
ELIMINATED
The only vibrations induced upon the stylus should
be (hose originating , —
from the recorded
grooves, Any others,
such as those present
in the apeakers, must
be iolated from the |
stylus, or it will repeat
edly tranamit thowe
apurious signals
throughout the aystem
ms 6 “pooustic feed-
banc.
Dual haa taken extra-
ordinary care in elimi-
naling anything that would tend to induce acoustic
feedback, For cxample, the spring-mounted foot.
ings (Fig. 23) are internally cushioned with robber
between spring and caps. Further, the springs them
eclves are “soft,” because the feathertouch sde-to
side action of the operating slide switches do not
require stiff vertical resistance,
Phe tonearm counterbalance is also robber-isolated
frown its shaft, a you will notice when handling it
(See page 2.) And the motor, of course, is thor
oughly insulated againat both shock and vibration
These are some of the “inside” reasons why you
will find Deal automatic turntables in the highest
quality single-cahinel consoles that can reproduce
the full frequency response range withoul concern
for acoustic feedback