Roland SVC-350 Operating and maintenance manual

SVC-350 SERVICE NOTES
SPECIFICATIONS
ROLAND VOCODER Modal SVC-360
INPUTS
MIC INPUT: 1/4 inch STANDARD
snone Jack or EIA-RS297
Connector iciOOonm. -54dBm mm.)
INSTRUMENT INPUT: 1/4 men
STANDARD Phone Jack HOOkonm,
OdB max.)
QUrTAR INPUT: 1-4 inch STANDARD
D*.one Jack dOOkonm. GUITAR
flaw level.)-lOdBmi75OmV)
INSTRUMENT LEVEL SELECTOR
Switch (OdBm. -i5dBm, -30dBm)
Jack
HLJ-OI9-01-030
(O09-046)
Jack
HLJ-O2 46-01-030
(O09-030)
INPUT LEVEL INDICATORS:
.ED DISPLAY 5
MIC LEVEL. Green. Red/over
INSTRUMENT LEVEL. Green Red'
over
GUITAR LEVEL. Green Red/over
OUTPUTS
For GUITAR AMPLIFIER: 1/4 inch
STANDARD Phone Jack ( lOkohia)
MONO or STEREO OUTPUTS: 1/4
inch STANDARD Phone Jack
Knot no.44 (016-044)
Pot. 3VH6PA361C14
(026-161)
CONTROLS
MIC LEVEL CONTROL
(,-5413111 to -14dBm)
POWER CONSUMPTION: 13W
DIMENSIONS: 482(W) x 92(H) x 350(0)
mm
WEIGHT: 5 • 3kg
Knob no.77 (016-077)
Pot. 3WJEJA320B14
(026-155)
Pot. EVH8MA361A14
(026-163)
Jack
HLJ-024-01-030
(009-030)
Switch
SSM-02308 (001-196
Knob no.77 (016-077)
rot. EVEEQA361314
(O26-158)
Knob no.48
(016-048)
Pot.
EVHHPS20B14
(029-589)
c MACHINE SCREW
t—-> 6-M4X10 BLK
Power 3w.tch
SDG5P001 (01-156) 100V
3DG5P0C1-2 ('01-216) 117V
SDG5P5O2 (01-217)
220/240V
Button
no. 9
(016-009)
Panel H58
(072H058)
HANDLE
108 H 00 3
RUBBER FOOT
K-15U11-C3'
CCVER
O65HO6O
MACHINE SCREW
6-M4X12 BLK
Haxa^a socket head bolt 4 x czim blk
Recectacle —(
NC-3PP or I-3M
(010-264)
MIC AMP Beard
AP-127 (141-127/
CONTROL Board
Switch
SSM-02308
(001-196)
Jack
HLJ-C264-1-030
(009-OP)
LED
TLR-124 (019-028) red
TLG-124 (019-029) green
Jack
HLJ-O261-O1-O3C
(009-037)
' Jack HLJ-O264-O1-C2C
(009-040)
1—Knob no.44 (016-044)
Pot. 3Wo"EJA320B14
(026-155)
OP-142 (149-142)
FILTER Board
FL-19 (145-019) 100. ll'V
FL-19D (14--C1C)D) 22C 240V
i— LED Board
OP-150 (149-15C)
r-Fuse Board
OP-143 100V
OP-144 117V
OP-145 220/24CV
Power
transformer
C22-028N
100V
022-028C
117V
022-028D
220/240V
Terminal
TT501D-1
(042-032)
Ground terminal
TT-9-4
(042-041)
Printed in Japan A3 1

Dec. 8,1979
HOLD
MIC
HOLD
IC53
ANALYZER
BPF
IC5O.55
FL-19
FILTERS
SYNTHESIZER FILTERS
OJ7
PEAK
METEC7&R
■LPF
5OHs
1
A
Kit f
r- SPF
/CA
BPF
:C2-7
EXPANDER -CONT
INSTR'
OT4
'red
IC45
PEAK
PETCCBR
K 2? (»B0) I
AIIIMO k—J
AUDIO
DELAY
J
Q3C
LPF
LPF
031
TC2K9 8BJ
AU&IO
DELAY
J
LPF
Oil
038
DIRECT 3IG.
CLOCK
OSC
AA
Q32-O36
CLACK
LPD-I
IC25
LFO'2
IC26.Q44
Q26
LNV-
icHz
DC
IC44
TRIAN6UU*
OSC
M ilL
33
IC39
IC38
VCA
IC37
A
8f«-3 Circuit
♦ DIRECT "ON"
fSi/3 i—■
AMP
IC12a
AMP
IC12b
l ' wt.
re i*
f
air
L.rt.M
ATT
I L.W.H
n
A (A-»B)
1
-B.
AMP
LEVCL
ENSEMBLE ON, OFF
'0 PHONES
SVC-350 BLOCK DIAGRAM

MOUII
IIUIM
-Deiail-
uec. 8,1979
CCMPR3USCR
After ampi— fled by 14-54d3 through Mic Head Amp or. Ar-127,
Mic 3ignal ijoea to id i,pin3 5-7) whoje gain i3 reversely
proportional to she control current from Q5 emitter.
The aic 3i,sr.ai coming from IC2 pin 7 La full-wave rectified
by IC3 (pir.3 5-7), Dl and D2, peak-voltage detected by IC3
Ipins 1-3;,D*, jncothed to DC voltage by IC5 (pir.3 1-3), ani
7-1 converted by IC4 (.pins 1-3),Q5 • Connected acros3 IC4'3
pins 6 and 7 in parailed with feedback resistors is IC1 3A6CJ.
As the mic si-gnai increases, Q5 output current increases,that
causes 3A662 conductance to increase, lowering the gain of
IC4 (pins 5-7; to retain either half peak output from $oing
above 10V (2OVpp).
In thi3 7oc oder, there are two other compressors similar to
the Mic compressor ir. configuration: in Guitar preamp ohain
and synthesizer filler output channe-.
SXPAIJDSR
Ihe output -voltage at pin 1 of IC5 io al30 received oy
3x?ander3 IC17-20, 322 and 32;. The current from 322 ^323)
varies in the same direction a3 in the Compressor, but with
thi3 fashion, 3igr.al flew rate through IC13 (IC2G/ is ii-
reciy proportional to the control current; the more current
flows, the moire signal flows through IC13.
ANALYZER FILTSR
Ten 3?Fs witri a nign Q consisting of ICs (s. g. IC<?G and
IC55; covers most of the audio spectrum - 3peech signal.
The 3ignal from the compressor is pre-emphasized through
IC5l?in3 5-7) and fed to the filter bank which slices up the
3pectrum. Each. 3lice goes to a iiode(e.g. D37) where its
peak is letected, 3moothed and is fed to the 7CA in the next
3tage filter -Synthesiser filter. This i3 a control voltage
that is proportional to *.he jtrer-ght of that slice.
J "/:.rTHE JIZEli ? IL :2h
Trie Jyr.th^ji»'.«r f-itor u a jet ^f oar.'i?-^ filr-jr, .ier.-
ticai to tnose of the Analyzer 3ection,iJfed by tne o.^n-
■ii •-•oming througn either IllSTRUMENT or joJAR preaap and
IlAiuMCIIICS circuit, i'he filter bank 3lice3 Jp instrument
3ound jpectrua into banas :n the 3aoe way Analyser filter
ioea on the jpeech 3pectrua. Each 3lice tr?n connects to
•/oit'dge— :ontroiied amp -7CA.
7CA
During an absence of signal in Analyser 'ilterie.g.IC5O
IC55.-C63), negative peaks of trian^alar *ve jn pin 1J of
IC33 is kept positive -determined by 7?.3 • with respect
to the pin 11, disnabling 3witcnir.g gata -iC;2.
When the voltage from ICc3 increases to . scae extent, it
exceeds lower portion of trianiguiar wave,au3ing IC33 pin
13 turns to "H" wnich in turn gates 1C32 :. When pc3itive
going triangular wave reaches above the /ctage on pin 11,
pin 1; tum3 to "L" and IC32 turns off. Ths signal flow
rate througn IC32 aepend3 sn the width of lulse :*r:a 1C33
and pulse width is proportional to -Co; ;;trcl ventage.
pul3e3ating rectified 3ignal3 are smoothedwhile tr.ey are
passing through the next fixter -IC39.
TOCCDiiR I1CLD
IC33 pin 10
IC33 pin 11
IC63 pin 7
IC33 pin 1
-rj n
HUH CCNSCIIA3T FILTER
This H?F allows only high-frequency cccc'-.ent -n signal
from tne Mic imp :o pass 30 aa to coaper.sa; f^r r.igh-
"requer.cy range .r.oapub^e .:' reprcciuc-.ior. : t.ie • :c :aer
rhu 'jirrj;; .j •: i.-npoj.jd ;f QC.Q3 'lnd Q.X. *hen the
KCLD jacit circuit :pen3, and 5Cm3 later, the Q2 output
mcrea3*3 in -.r;-* positive-going to turn on tne gate Ql
and to jnunt 175 0 input to the ground. On the other hand,
a 3ignal supplied through D7 turns FST 3witch IC53 (pins
10-12) on, turning 1C53 (pins 3 and 9) off, disconnecting
H3O7 from iiscr.argir.g path, increased discharging time
constant can r.old previously charged C135 for 7-10sec.
7CICS JHARACTCR CONTROL
Because resi3*or3, -R726,728, 730 connected to
wiper terminals of CHARACTCR CONTROL pots, are different
in value; the higher the frequency, the ^arger the value:
overall frequency response offer3 de-emphasized charac
teristics .
SOUNU DETECTOR
During an absence of musical instrument's signal,7cccder
3hut3 inadvertent 3ignal3 in under the coordination of a
system. The sound detector i3 the first 3tage of the
3y3tem.
IC45 (?in3 ~-~}, D51 and D52 make up a full-wave recti
fier, the average output voltage is peak of the 3ignal
ielivered by IC21 pir. 1, then IC45 (pins 1-3) provides
adequately smcctn ^C output from pin 1.
•hen this vc.tage - at pin 4 of IC37 - exceeas voltage
at pin 5, pin I goe.s to negative, cutting Q29 off, removing
the ground rrea pin 2 of 1C17(IC19J. Expanders are now
ready to function.
IC37 pin 7 al3o 3ees Sound Detector's output and deter
mines pin 1's output pulse rfidth which in turn regulates
H?F sigriHl flaw rare. While Synthesizer filter 7CA re
sponds to s^e-izr. 3 peer rum, H?F .'CA to tne instrument' 3.

CIRCUIT DESCRIPTION
—General-
Sound from Musical Instrument
Voice
from
XIC
High Sound
3yr:as3 Filter
Com
pressor
1st
Filter
Amplitude
Detector
Sound
Detector
2nd Filter
-*• VCA •*
Sxcander
Holi
In the Vocoder, the voice signal from a Mic is frequency-analysed
through a group of filters to slice up a voice signal frequency
3pectruna featuring huaar. voice. Then the spectrum is duplicated
to another group of musical sound signal filters to obtain func
tions equivalent to human acuth and throat and thus to simulate
human voice with musical sound signals.
Fundamental Vocoder functions are discribed below according to
t.ie Blocsk Diagram shown above.
1. Analyzing (first) Filter and Amplitude Detectors
A Mic iixput signal is resolved by a group of filters into freqen-
cy band components which are amplitude-detected and supplied tc
the VCAs of the Synthesiser Filter (second filter).
Signals passing through second filters are. controlled in volume
at VCA b.y the control signal coming from corresponding frequency
band of tne first filter.
Z. Synthesiser ,'3e;or.a; liter and "CAs
Like the first filter, aausicai 3cund signal
being supplied is resolvd into frequency
spectrum components. Sise a musical 3ound
passing through the 3ecori group of filters
is proportional to the f*st filter output
amplitude, the spectrum £ the second filter
output is analogous to trit of the vcice
signal. In ether words, :he second filter
output is mixture of trie input musical
3cund signal and the firs: signal output.
Thus, uniform 3ound signa. spectrum would be
ideal for reproduction of human voice, but
it is no longer of a musi:al instrument.
3• Compander
The compander is a combination 3f a
compressor and an excajier.
The compressor reduces a a ic input signals
range in amplitude and su: plies smaller out-
cut signals range than inj ut signals' to the
first filter.
On the contrary, the expan der, for a given
range of amplitude input v oltages, produces
a larger amplitude range o f output voltage.
Thus restores the ordinal volume range.
i. Kigir. Frequency Voice Signjil Bypass
Filter \Reiionant Filter)
3mce musical sounds rarely include high frequency
r.oise components such as "fricative" may be in
V.ioe, the second filter has no spectrum to respen:
to. Furthermore, such a sound, hardly relating t:
musical intervals, is separated from a mic inpu"
signal, passes through this circuit and is re-
ccmbined with the second filter outputs.
5. Musical Sound Signal Detector
This circuit -obstructs tne second filter output a;
long as a musical sound is not supplied to the
Vocoder and tells the circuits 3 and i whether a
musical scur.d signal is being fed cr net.
Thi3 circ .it enables Vocoder to hold its output
luring an interruption in mic signal,e.g. when a
singer inspires, -he function can also be used for
some special effect applications.
During holding, this circuit retains spec trams and
volume by holding amplitude ietectors output volt
ages and expander control voltage.
Tne compressor gain is minimised and the vcice gate
is turned off so as to 1-ceep vcice unchanged ever.
though ,Xic input singal is changing.

OP-150 (149-150)
FUSE BOARD AC CONNECTIONS
1OQV
o
]ECGHJIA473M\
022-028*
0P-143A
(149-143A)
POWER $W. SD4-SP-00I-I
OOZS
117V
ECQ-UIA
473 MC
022-029 C
II7V
0P-144A
(149-144A)
POWER SW. SD(rSP~Q0/-2
QOI-ZI6
8SO,84OV
O
&CQ€2A
47JMQ3.
022-02M D
POWER SW. $D<k- SP-SQ2
ooi-2\n
OP-145A
(149-145AJ
(Etch mask 052H185A)
022-0UD
3lee'- nut r.o.lr -
Jxl2im (120-01=)
LED TLR-124 red
(019-028)
Connector assy
(G53-3S3)
PG3 O52H195
Polycarbonate collar
AP-127 (141-127)
(Etch mask 052491)
MIC LBTfiL
TRIO
3T/H6?A361C14
(026-141)
0
0
HLJO19O-O1-03O
(009-046)
CD
o
CO
2SC945-P
2SA733-P
Electrolytic
Maylar 507 Z
Ceramic 50V K
Resistor -J-w
3ALANCI1
(026-155)
3VAHHPS20B14
OP-142 (149-142) View from foil side
(Etch mask 052492)
T/R22 21 20 19 18 17 lo 15 14 13< 12
701'JMI I BWJ-3JA32OB14
(026-155)
•Hill
HARMONICS
BVH-BQA361 314 (026-153)

PL-19D (2 20/2407 V3RSIGN): WITH FUSES
FL-19 (145-019) (pcb os249O)
O SYNTHESIZER FILTER
O ANALYZER FILTER
5O45-1CA
o
o\
o
o
s * 8dsado flogs®®
5O45-O6A
ENSEMBLE (DELAY CIRCUIT
o
5C45-CMA
o

PARTS LIST
072H058 Panel H58 front
O65HO6O Cover (case) H60
1O8H003 Handle H3
111-037 Rubber foot K-15
O61HO?2 Chossis HQ2
016-044 Knob no.44 MIC LEVEL.VOLUME
016-077 Knob no.77 rotary samall
016-048 Knob no.48 slider
016-009 Button no.9 blk power switch
t'10-264 Receptacle NC-3FP or D-3M
009-037 Jack HLJ-O261-O1-O3O
009-040 Jack HLJ-O264-O1-O2O stereo
nm-0?0 Jack HLJ-O264-O1-O3O
0O9-046 Jack HLJ-O19O-O1-O3O headphones
001-156 Switch S1XJ5F001 power 100V
«'01-r?l6 Switch SDG5POO1-216 power 117V
001-217 Switch SDG5P 502 power 22O/24OV
001-195 Switch SSMO23O8 slide
100/117V
22O/24OV
mic
control
LED
145-019 FL-19 (PCB 052-490)
145-019D FL-19D with fuses
141-127 AP-127 (PCB 052-491)
149-142 OP-142 (PCB 052-492)
149-150 0P-150 (PCB O52H195)
Fuse PCB (PCB O52H185A)
149-143A OP-143A 100V
149-144A OF-144A 117V
149-145A OP-145A 220/240V
FUSE, FUSE HOLDER
Fuse SGA 1A prim, 100/117V
008-026
008-0 2r^
Fuse CEE T500mA prim.sec.
22O/24OV
012-003 Clip TF-758
022-028N Power transformer no,28N 100V
022-028C Power transformer no.28C 117V
022-028D Power transformer no.28D 22O/24OV
022-122 Output transformer MT-31 headphones
SEMICONDUCTOR
or
MPC177C
O1T1
n
H 13 1? ii in
bbd MN3010
U U LJ
u u
(Top Vi»w)
DUAL OP AMP
;iPC4558C TL082CP LF353N
TOP VIEW
A OUTPUT (T)C
B OUTPUT
B -INPUT
B +INPUT

SVC-3
SVC-350
CIRCUIT DIAGRAM
-/.I, ~ I
K»9B»L8 KOSVUTW
o
WttSS
I Mill
noise killer
Circled numbers except for those on connecting terminals are TB3T
"... Identical letters in the circles are lnterconneoted on the PCB.
j

uec.o,
triangulnr wave "c* *
sou. cutofI
ICD

SVC-350
Dec. 8,1979
28N 100V
28C 117V
28D 220/240V
-^l headphones
0
-0
POTENTIOMETER
026-163 EVH8MA361A14 lOkA solder terminal
026-161 EVH6PA361C14 TOkC
026-l^b EWJEJA32OB14 10kB x 2
026-158 EVHEQA361B14 lOkB 361-K2O
029-589 EVAHHPS20B14 lOkB slider
030-461 SR19R 2.2k trimmer
030-47-1 SRiyR 100k trimmer
E _
C -
B -
2SA733(P)
2SC945(P)
B
C
E
2SD234K))
2SB234(O)
amp
ator
(Top Vie-w)
—0 Vim i Irimintl ll i
CAPACITOR
032-191 ECEA16N1O lOmfd 16V non-polar
ECEA5ON1 lmfd SOV mm-polar
ECQ31151JZ 15Opf polystyrene
S
G
D
2SK30AIY)
2SK3OA(GR)
1OQ.117V
KCQE2A473MCS 0.(M7mT<i polypropylene
032-228 CB15B1V4H7 4.7mfd ?SV k tantalum
MISCELLANEOUS
064-265 Holder no.265 PCE retainer
right angle 3y6mm long
064-200 PCB hulder(fastener/spacer)
DLCBS-6N
120-015 Sleeve nut no.35 3x12mm
(spacer or stand-off)
073-037 Polycarbonate collar "5x6x18mm
LED
042-032 Terminal TTS01D-1 2p mains
042-041 Terminal TT-9-4 ground
048-001 Heat sink no.l
123-013 Hexagon socket head bolt 4x8mm
065-268 Cover no.268 dust cover,slider
065-261 Cover no.261 dust cover,slide sw.
2SB605
1 . KmiHer
2 . Collector
3 . Rise
Quad Comparator
. AN6912
Connection Diagram
(Top View)
DUAL *0" TYPE FLIP FLOP
TC4013P
10c 1
U*C2
ICLOCKC 3
1CLEARC «
1DATAC 5
1 PRESET C f>
GNDfl 7
13 32g
12 320
11
32CT/X1
10 32CLEAR
9 32DATA
B 32PRTSCT
CD4O66BE
our
oirr
v-Q
rm.n.t U i
1A4E
COS/MOS Quad Bilateral Switch
For Logic Syflemt AppIicMtom m Amnptx.
Mttitsry, and Critic^ tndusirisi Equtpmwii
Sped*! Fe*tvr*t:
■ 1S-V riijitri or t ?.5-V ptrt toptf* fwitcftim
• ton lypiol ON fMlMMM* Iw 1S.V op^atiM
CJI r*tkt>»o» mmnimd to withm S II o*«r IS V
* h£i part topwh ■%*•! rvifi

.5. 7GCGBER JCUND 3GMP.HBSJCR JAI3
ADJUSTMENT
1. MIC :CMPR-3SSCR JAIN
licH 3ine -50d3m
oscilloscope
LEVEL: 9
Make 3UT9 th~at the Red LED on the MICRCPHCNB
section goe3 on and stays on in above 3et-up.
Adjust TR-l for 20V?p at TP-2.
2. GUITAR COMPRSS30R GAIN
Peed a 3igna-l, 1kHz, sine -lOdBm
into JUITAR Input jack.
The Red LED on the GUITAR
section shou-Ld light and stay on.
Adjust 7R-2 for 2OVpp at TP-6.
Vlavefora Che-eking
With HARMCNECS knob turned fully clockwise,
a waveform similar to the waveforms in the figure
bellow 3hou2_i be seen at TP-2O.
Peed a signal,IkHs,Jir.e, J[p 12
OdBm, into TP-35.
Adju3t 7R-3 for 2C7=p
at TP-12.
•11": top
""vertical
—LqINPUT
To make 3ure of the compressor function, slide /j.cb "11" lown to
lowest. -he waveform has just reduced to a acme extent
(,depends on knob'3 traveling 3peed) is ri3ing anc ''ill 3top when
it reaches half an amplitude of earlier.
4. 7CA TRIANGULAR VA73FCRM FR3QU3NCY
Use a 10:1
probe for
trace
clarity.
■/ .:i-.--
ov
Adjust 7R-9 for 5-us per:cd.
5. 7CA CUT-OFF 3IA3
Feed white nci3e, lVpp into GUITAR
input jack.
31ide up JtURACrOR CONTROL FREQUENCY
knobs "1" to "1C" to the top.
Adjust 7R-3 until the noise signal just
disappears. Excessive turn will result
in low 7CA output.
MOTS
If this adjustment failed noise reduction, slide io-m the knob3
individually. The signal leaking through a filter will decrease
as the corresponding knob being 3iided down. Che ck tne Analyser
and Synthesizer filters in that frequency cr.3ir. r or malfunction.
OSCILLOSCOPE
O
VERTICAL
INPUT
Place a grcund on TP-15•
Plug a clank plug into
SN3EMBL2 ^acic to open the
jack circuit.
a. Connect TP-16 to a ground.
Adjust 7R-J. 30 that TP-17
becomes Z7 DC.
b. Connect IP-19 to a ground.
Adju3t 7R-= 30 that TP-13
beccme3 j'I DC.
7. 3XPAN32R JAIN
Feed a signal, 1kHz, sine
-3d3m ir.tc TP-15.
Connect Tr-lo ar.d TP-1? to
the grcur.i.
a.Adjust 7R-5 for 3Vpp at TP-17.
b. Ad just 7R-;- for 3V?p at TP-13.
VERTICAL
—pO INPUT
3BD M0DULATI3C 7C0 iA7E?0RM CHEKING
T = 4.-5sec vapprox.)
at TP-;C ov
_ -107
T = 0.2-0.2?sec
at TP-31
B = 177?? a: IP-33
OV
T = ijus-lrus (apprcx;
at r?-:5, tp-29
<•••>< i •••••• |
Being modulated by the composite sigr.aiiair.e and triar.glular
waveforms), the waveforms at TP-2= ar.i TP-i9 3wee? 3lowly
with :3gslir.g.