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How Kenwood Engineers Designed
The New KX-1030
With
Extended
Frequency Response,
Lower Noise
%
And Lower
Distortion
Using A
Three-Head
Design
inches).
It is this minute and optimum
gap width that
is largely responsible for
the
extended
frequency range and wider
dynamic range
of
this cassette deck. In
addition,
the depth
of
the head gap is
maintained
at
100
microns
for
higher
playback
sensitivity.
grams-em".
Only
when
one compares
this
with
the kinetic energy
of rotation
of
conventional
decks
- which ranges
from 600
to
1700
grams-em?
- can one
fully
appreciate the
importance of
the
massive flywheel used in
the
KX-1030.
As
a result of this high
kinetic energy,
flutter
(perceived
audibly
as
a
rapid
warbling of
recorded
sound),
and
wow
(perceived
as a
slower wavering
of
musical
pitch
caused
by
mechanical
variations in
the
tape
drive system)
have
been
reduced
to the low
level
normally
found
in
high
quality
open-reel
machines.
•
•
Wow & Flutter
Characteristics
High
Power,
High Torque DC Servo
Motor
While the use of a large flywheel in a
cassette
deck's
transport
system con-
tributes
significantly
to
stable
and
accurate
rotation of
that drive system,
driving
such a
heavy
flywheel requires a
motor
with
high
rotational
torque.
Kenwood engineers have incorporated a
motor with
a
rotational
torque of 50
gram centimeters
in the KX-1030 -
compared with approximately
20 gram
centimeters
of torque provided
by
the
motors
used in
many
other cassette
decks.
Another
important
feature of
this well designed DC servo motor is
that
a
sudden increase in load (often
encountered
in cassette
drive systems
when
less-than-perfect
cassette
tape
housings are used)
has
a negligible effect
upon
the stability
of the tape drive
system.
Although
some dual purpose
record/
playback
heads
incorporated in
conven-
tional cassette
decks
provide good
per-
formance,
the
use of
combination heads
to
record and reproduce
tapes
impose a
limitation
in
terms
of
frequency
re-
sponse
and dynamic range.
The most
important
factor that deter-
mines recording and playback response
is the gap width
of the head. For
example,
the gap width of a playback
head
is
a critical factor in
determining
the
high-frequency
capability
of
cassette
decks. A
signal recorded on
tape may
be
thought of as
having a wavelength which
is inversely
proportional to its frequen-
cy. As the signal
frequency increases,
its
wavelength
becomes
shorter
and
shorter.
When the wavelength
to be
recorded
approaches
the width of the
playback head gap in
length,
the play-
back head can no longer produce an
output,
and
response falls
off
drastically
at that
point.
Ordinary
Rec./P.B.
Head (Wide Gap Width)
The
Kenwood dual combination
record/playback
head
Frequency
Responseof
Rec. Head Using
Various Gap Widths
rrn
rr-l iT I
e
Gap WIdth
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Reco~
tOad
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.
6
-=t
4
110
4.
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Ip;j
1-=/'
2.
,
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.
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0
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I
4-1_
II
6
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.;
11111I
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+--1
1111'11'
II'
i
I'
10
10
01
[}'SlOrtlon(%)
Output vs Distortion of
Rec.
Head Using
Different Gap Widths
A Precision Die-Cast Zinc
Alloy
Flywheel With A Mass Of 150
Grams Provides Greater Inertia And
More Accurate Tape Motion
/
ShO<! wavelength
rnaqnetic
field
~~==
Gap
width
KX-1030
Playback
Head (Narrow
Gap Width)
___
-Playback
head
"Short
wavelength
magnetic
field
.L.
---H~
<,
Magnetic
tape
Gap
width
.
In order to extend the frequency range,
the gap width of the playback head used
in the KX-1030 is held to
less
than 1.5
microns (a micron is equal to 0.00004
Another
aspect of the
extraordinary
performance of the new KX-1030 arises
from
its ability
to provide
accurate,
constant
rotation of the tape
capstan
shaft - the most
important
element in
driving the tape. Kenwood
engineers
recognized
that
the tape-drive
motor
alone cannot
absorb speed
variations
in
the tape drive system.
Accordingly, they
incorporated a
massive
flywheel (with
a
weight
of
150 grams)
to increase
kinetic
energy
of rotation
to a high 5,460
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