Dual Catalog 1980

Page 1

Thieyear
all Dual

Tumtablee
feature ULM

The Ultra

Low Mass
tomearm .
and cartridge
system

Page 2

ULM m...

breakthrough
in record playback
technology.

To appreciate the significance of
Dual's new Ultra Low Mass tone-
arm and cartridge system, you
need a clear understanding of
what happens when the stylus
tracks the record groove. And
there is much more to it than
meets the eye.

If all records were perfectly flat
and perfectly concentric, the stylus
would have only the contours of
the recorded groove to contend
with. To reproduce music the
stylus is forced to change direc-
tions-up, down and sideways-
from 20 to 20,000 times a second.
Thats enough of a challenge.

Not so well understood, how-
ever, are some of the other forces
that also affect the way the stylus
moves-forces that introduce disa
tortion to the music.

Warp is the most serious of
these forces.

The realities of record manufac-
turing today result in most records
being warped. And even when

The potential for an Ultra-Low-Mass
system has long existed in Dual's straight-
line tubular tonearm with its four-point
gyroscopic gimbal suspension. The tone-
arm mass is centered at the pivot point.
The Vernier-adjustable counterbalance
establishes zero balance with micrometer-
like precision. A tempered flatswound
spring applies tracking force directly at the
pivot-without increasing effective mass.

ULTRAI It (M ASS

warps are barely visible, they in-
terfere with accurate tracking.
The stylus must follow the groove
whether its flat or warped. And
how well it follows the warps is a
function of tonearm and cartridge
engineering.

The heavier the tonearm and
cartridge, the more the stylus will
tend to dig in when it rides up the
warp and to lose contact on the
way down. This is a natural result
of inertia-the tendency of an ob-
ject at rest to remain at rest and in
motion to remain in motion.

The amount of inertia the tone-
arm and cartridge present to the
stylus is determined by their
total effective mass-the moving
weight of the combined tonearm
and cartridge as it affects the sty-
lus in motion.

Total effective mass is measur-
able. Conventional tonearms and
cartridges have a total effective
mass of approximately 18 grams.
(Some are even higher.)

To determine precisely how
much total effective mass affects
the tracking of warped records,
Dual made a special test record. It

i
I

i
l
l

i

And the tonearm remains in perfect
dynamic balance throughout play, even if
the turntable is not level. This basic design
has now been reengineered-with a lighter
head and counterbalance, and a slimmer
tube-so that it can accommodate cart-
ridges weighing as little as two grams.

has a 300-Hz test tone and care-
fully spaced 1.5 mm warps-
typical of those on today's records.

In an extensive series of tests,
18-gram tonearm and cartridge
combinations generated an aver-
age of 2.7 percent total harmonic
distortion. (Anything over 1.0 per-
cent THD is considered audible.)
Also, tracking force varied as
much as 30 percent from warp to
warp-an action which reduces
stylus and record life.

Playing the same record under
the same conditions, the ULM
tonearm and cartridge system-
with only 8 grams total effective
mass-reduced THD to an aston-
ishingly low 0.01 percent. That's
a reduction of 270 times!

Another form of distortion re-
sulting from warped records-
frequency intermodulation distor-
tion (FlM)-was also measured.
lt's known as "warp wow, and
you hear it as an unpleasant
warble. With the ULM system,
FIM measures half that of conven-
tional tonearm and cartridge
combinations.

The benefits of ULM are clear in

The ULM cartridge series results from a
collaboration between Dual and Ortofon
engineers. These cartridges were designed
to match Duals new ULM tonearm so that
the combined tonearm and cartrid re mass

would be optimized-at 8 grams. he ULM
cartridge itself weighs only 2.5 rams
includin mounting bracket an hardware.
The ULh§ cartridge is a moving-iron type,
based on the variable-magnetic-shunt
(VMS) principle. It is miniaturized in many
respects. including the stylus tip. Among
its important specifications: Frequency
response from 10 Hz to as high as 30,000
Hz; channel se aration as much as 28 dB,
and shielding rom hum better than 10 dB
over conventional cartridges.

All Dual turntables feature ULM . . . the Ultra Low Mass
tonearm and cartridge system with only 8 grams total effective mass.