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Korg ddd-1 Service Manual

Korg ddd-1
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KLM-6023
(LED
circuit
board)
The
PEAK
LED
and
TRIG
LED
light
according
to
the
AUDIO
IN
status.
KLM-6007
KLM-6007
is
the
power
supply
circuit
board.
The
out
put
voltages
are
as
given
below.
KLM-6008
a
IC2(78M05)
+
5V±5%
b
IC1
(79M05)
-5V±5%
c
OPTION
BATT
+
9V±10%
d
Power
supply
for
use
AC100V
(effective
value)
±10%
Circuit
board
KLM-6008
is
a
circuit
board
for
only
the
wiring
of
the
ROM
card,
RAM
card
and
sampling
board.
It
consists
of
a
CPU
bus
and
GATE
ARRAY
bus.
DSB-1:
Description
off
Circuit
Board
(1).
DSB-1
has
one
gate
array
(pPD65010)
on
circuit
board
KLM-6010.
It
is
controlled
by
data
from
DDD-1
and
per
forms
sampling.
It
can
be
easily
understood
by
con
sidering
that
it
has
only
the
sampling
function
of
other
devices
which
have
an
identical
gate
array.
<
Explanations
of
Individual
circuits
>
1.
INPUT
FILTER
The
input
signal
from
DDD-1
(voice
signal
input)
is
filtered
by
the
fc
=
19kHz
5th-order
Chebysheu
low-
pass
filter
to
prevent
sampling
block
and
beats
from
occurring.
2.
PRE-EMPHASIS
+
COMPRESSOR
The
signal
which
has
passed
through
the
input
filter
is
pre-emphasized
by
the
RC
of
C56
and
R50;
then
dynamic
range
is
compressed
by
the
compressor
cir
cuit
formed
by
the
compounder
IC
(1/2
IC20;
MPC1571C).
3.
SAMPLE
&
HOLD
CIRCUIT:
input
side
The
sample
and
hold
circuit
which
digitizes
the
input
signal
consists
of
an
13700
(1/2
IC10)
and
FET
(F1);
the
13700
(transconductance
amplifier)
is
used
as a
high-speed
analogue
switch.
Also,
the
control
signal
which
controls
that
switch
operation
is
automatically
produced
by
the
gate
array
(IC7)
and
output
from
pin
18
"SH"
of
the
gate
array.
This
frequency
is
called
the
"sampling
clock".
4.
A/D
CONVERTER
The
circuitry
which
performs
A/D
conversion
of
a
signal
that
has
been
sampled
and
held
is
incor
porated
into
the
interior
of
the
gate
array,
but the
high-speed
converter
(IC11)
and
the
sequential
com
parison
data
output
D/A
circuit
are
attached
to
the
outside.
This
converter
performs
sequential
com
parison
A/D
conversion.
5.
GATE
ARRAY
Gate
array
exclusively
used
for
delay:
NEC
pPD65010.
6.
D/A
CONVERTER
The
effect
signal
that
has
been
processed
by
the
gate
array
(IC7)
is
output
as
12-bit
digital
data
to
DO11
to
DO0
(pin
20
to
pin
31).
These
data
are
converted
to
analogue
data
by
the
R-2R
ladder-type
resistor
(BLOCK
R).
This
signal
is
used
as
the
output
side
sample
&
hold
circuit
input
signal
and
as
sequential
comparison
data
for
the
gate
array
input
side
A/D
conversion
comparator.
7.
SAMPLE
&
HOLD
CIRCUIT:
output
side
The
effect
signal
(digital
data)
from
the
gate
array
is
sampled
and
held
by
a
13700
(1/2
IC10)
and
FET
(F2),
similar
to
the
way
the
D/A
converted
signal
(analgue
data)
is
sampled
and
held
on
the
input
side
(explained
above).
8.
OUTPUT
FILTER
This
is
a
5th-order
Chebysheu
low-pass
filter
(fc
=
16kHz)
to
remove
the
sampling
clock
compo
nent.
9.
DE-EMPHASIS
+
EXPANDER
The
dynamic
range,
which
was
compressed
on
the
input
side,
is
restored
to
its
original
condition
by
the
expander
circuit
formed
by
the
conpander
IC
(1/2
IC20;
mPC1571C).
In
addition,
by
sending
the
gate
ar
ray
(IC7)
mute
signal
(pin
15:
MUTB)
to
the
circuit
formed
by
ZD
,
R62
and
D6,
the
expander
circuit
is
forcibly
shut
off
so
that
unnecessary
signals
are
not
passed
on.
The
signal
which
has
been
restored
to
its
original
condition
is
de-emphasized
by
the
RC
of
C61
and
R59.
29
Scan by Manual Manor
http://www.markgllinsky.com/ManualManor.html

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Korg ddd-1 Specifications

General IconGeneral
BrandKorg
Modelddd-1
CategoryDrums
LanguageEnglish

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