Roland TB-303 - B. INITIAL SETTINGS

TB-303
Feb.19,1982
VCF
ENVELOPE
MODULATION
In
the
conventional
VCF
configuration^ envelope
modulation voltages
applied
to modulation
control
voltage
input
of
VCF
rise
from
a
fixed
potential
to their
values
regardless
of shape
and
amount of
envelope
and
fall
back
to
the
same potential. Fig. 1 . In this
setup,
an
attempt
to
deepen
envelope
modulation
is
increment
of
control
voltage
In one
direction, only
to open
up
fitter.
Resultants are; higher the
control
voltage
input,
longer
the
period of
time
cxjtoff
point
travels
through
higher
frequency
range
in
which
significant
aural
sound
characteristic
changes
do
not
occur,
whereas
notes
are
brightened.
To
compensate
for
the
limitation
this Impose, there
is a gimmick
in
the
TB-303 VCF circuit.
The
09
has
a key
role
in
this
arrangement.
See
Fig.
2.
It
developes
bias
for
Q10
and
Oil
to
set
initial
cutoff point
at
the
center of frequency
range.
Within
the range
even a small amount
of
voltage change
can
aaate
a
appreciable
modulation.
Rq.1
Fig. 3
Fig.
2
Rotating
wiper
(|)
of
VR5
closer
to
terminal
(3)
increases
EIW MOD
voltage
being
fed
to
base of
QIO while
changing
the
bias
which in
turn
lowers
VCF
cutoff
frequency.
See
Fig.
3.
This
is equal
to turning
CUTOFF
knob
counterclockwise
and,
since
QIO
and
Oil in
combination
convert
control
voltage
to
the
current
in
amt-log
fashion,
the
cutoff
point
stays
in
an
effeedve
frequency
range
for
the
most
portion
of
envelope
sweeping
duration.
PARTS
UST
PAMEL
2201 061 SOO
Top
case N615
top
2201061400
BoTtom
case
N-614
bofttom
2202062300
Battery
cover N-623
2202062400
Battery
holder N^24
2221027700
Sub
parcel
N-277
SOCKET
13429706
01 N conrucior TCS0737-01-010
Sync
13449218
Jack
HU0306-01-030 MONO
13449217
Jack
KU0305-01-010
STEREO
13449401
Jack
S68C26
MINI
13^49706
Adaptor
Jack HECM70-01-230 AC
adaptor
TRANSFORMER
COIL
12M92I7
IFTooM
S74230 (yellow)
CPU
clock
12449507
MC102C
OC-OC
oonverter
SWITCH
13119601
SRMIOI?
rotary TRACK,
INSTRUMENT
13119303
SRM1034
rotary
MODE
13129715
KHC10901
push
All
switches
on
the
switch
board
13159114
SSF2-22-07
slide
SYNC
In/out
SEMICONDUCTOR
LSI
151
79128
;iPC0650C'133
CMOS
CPU
1S179305
pP0444C
CMOS
RAM
1C
1$159101K0
H014001BP
Quad
2-input NOR
gate
1B1S9106
HD14013BP
or MN4013B
[>u«l
typ«
D
flip-flop
1512912a
HD14(K0BP
Hex buffer?
15159116
HD140668P
Quad
analoff
Mfitdt
POTENTIOMETER
Quad
multiplerer
13219333
K161100FAE-1MC
tempo
15159133
HD14174BP
Hex ty:3e D
flip-flot
1321K134
VM1
1
R851
A-5MU11-50KA
master
vol.
&
power
twitch
15159306
H014666BP
[>ual
bmary to
1*of
^
13219331 K161B0-S0K8
TUNING,
ACCENT
0«cod»r/0«nultip<
-«er
13219340
K16l80-50kA
CUT
OFF
FREQ, ENV
MOD
15189138
AN6562
Oualopanip
13219339 K16tB0-lMA
DECAY
15229802
BA862(A1
Vari-oondijctanoe
»np
13219774
K162TOOW-50k6
x
2 resonance
151593O3H0
HD145848
Hex Sdvnitt
lrigge«
13299116 H1051A01&4?kB
trimmer
15199509
LA4140
AF Power amp
13299119 Hl051A021-220kB
trimmer
13299122
Hl06lA023-47QkB
uimmer
TRANSISTOR
13299543
H1021A011-4.7kB
trimtner
15119105
2SA733(P»
RESISTOR
15119602
2S9647(C)
12559706
FRM0
2.70 Fute resistor
15119606
2S8596(0)
15129602
2S0667(C)
CIRCUIT BOARD
ASSEMBLV
15126121
16129130
25WU21
(nj
2SC1563{F)
Dual
Tr
7312706010
MAIN
BOARD
OP3127-060
IPCB291 S02C)
15129131
2SC2291
(FI
Oval
Tr
7312704010 SWITCH
BOARD
0P3127-040
(PCB
291 603C1
FET
KNOB
15139101
2SK30TM{Y)
2247019400
Ki>ob
N-194
matter Vft
ft
TEMPO
15139102
2SK3aTM{0)
2247019500
Knob
N*195
imtrumcni level
2247019100
Knob
N-191
R
un/stop,
tap
1 ert
2247019200
Knob
N'192
step number
2247019800
Knob
N-138
rotary
twitch
15029109
GL3AR2
OTHERS
DIODE,
1299503
PCB Holder
LC8S-12NS
15019120
1S2473
Si
diode
2219028700
Holder
N287
Potentiometer for
master
vol.
ft tempo
15019209
&55006
2343097600
Flat cable
8-core
16019122
1S-188FM
Qt
diode
2343097700
Flat
cable
4-oore
1501965$
RD6.8E8-3
or
15019656
RD6.8€fi2*T
2345012500'
Termtrtal board
Bantry
+
lidi
15019653
R016EB-3
2345012600 Termirul spring
Bantry
—
side
15019126
1$5-133
Si diode
2224011500
Dust
cover N-116
tiidt switch
15019630
15B46A
2224050600
Dust
cover N-50G
master vol., cempm, rotary
switch
8