Yamaha JOGR JOGRR CS50 Servicing Manual Download

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Summary of Contents for JOGR JOGRR CS50

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Page 3: ...EY Coder 16 KEY Assigner 16 KEY Voltage Detecting Circuit 20 Basic Construction of KEY Voltage Detecting Circuit 20 PIN terminal Description of LSI YM26700 20 Timing Clock rp SC SC8 21 Operational Principle I of KEY Voltage Detecting Circuit 22 D A Converter 23 Operational Principle II of KEY Voltage Detecting Circuit 24 Port3IDento Operation 24 Operational Principle lli of KEY Voltage Detecting C...

Page 4: ... ofVCF EG Operation Expression Circuit Output Amplifier and Headphone Amplifier Modulator Circuit I PWM Oscillator Circuit 2 Ring Modulator 3 Sub oscillator and Touch Response Control Voltage Mixing Circuit 1 VCO Vibrato Control Voltage Mixing Circuit 2 VCF Cut OFF Frequency fc Control Voltage Mixing Circuit 3 VCF Resonance Q Control Voltage Mixing Circuit 4 VCA Control Voltage Mixing Circuit Othe...

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Page 6: ...NG LONG LONG 10 10 LONG LONG 10 LONG 10 III g IItititii IIIItti SLOW 0 50 0 LOW LOW LOW LOW 0 0 SHORT SHORT SHORT 0 0 SHORT SHORT 0 SHORT 0 SPEED PWM PW L NOISE HPF RESH LPF RESL IL AL A D R VCF 0 J A D S LEVEL R LEVEL vco VCF TONE SELECTOR TRANSPOSITION r TOUCH RESPONSE RESO BRILL NANCE ANCE vco VCF BRILLIANCE LEVEL It Jll T I IIOCT I IIrI VOLUME STR STR BRASS BRASS f LUTE ELEC CLAVI HARPS GUJ GU...

Page 7: ...PN 3 r RINI MODULATTOR ATTACK DECAY MODULA RESO BRILLT TIME TfME DEPTH SPEED TTON NANCE ANCE IIIII It PORTA SUSTAIN MENTO I II GL SS J J I lANDO 1Il II SLOW 0 0 0 SHORT SHORT FUc C SPEED VCO VCF VCA PORTAMENTO TIOCI SUSTAIN GLISSANDO TONE SELE STR STW BRASS BRASS FLUTE ELEC CLAVI HARPS Gl ING lNG TRIC CHORD CHORD V PIANO 2 ...

Page 8: ...SHORT SHORT SHORT 0 0 SHORT SHORT 0 SHORT 0 ESH LPF RESL IL AL A D R VCF A D S R LEVEL LEVEL VCF VCA E SELECTOR HARPS GUI GUI FUNKY FUNKY FUNKY PANEL J CHORD TAR TAR 2 2 3 TRANSPOSITION Connected to Foot controller jack TOUCH RESPONSE VCO VCF BRILLIANCE LEVEL rrrr L_ SUB OSC _ J VOLUME 0 HEAD PHONE EXP PEDAL ...

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Page 10: ... principles of the synthesizer This manual contains detailed descriptions of the construction and operation of the various circuits and the functions of the IC s used in them for Model CS 50 Since each of the circuits employs digital technologies it is essential to understand the fundamentals of digital technology before reading the manual In order to service a CS thorough mastery of this manual i...

Page 11: ...called the square wave The signal includes the odd numbered harmonics and is best for synthesizing tone colors like those of the clarinet For a waveshape with a larger duty ratio as illustrated at the left the signal also includes the even numbered harmonics and is best for synthesizing tone colors like those of the trumpet PW Pulse Width This lever changes the duty ratio from 50 to 90 allowing va...

Page 12: ...ant tone color fc fc L t __ _f fcl fc 2 Fig C RESH Resonance High High pass fJ lter Resonance Amplitude fc Fig D Adding resonance to a high pass filter causes the fllter to emphasize a band of frequencies just at the cut off point Resonance is extremely important in the synthesizer filters Almost every mechanical instrument has its own characteristic resonances and in order to simulate close to na...

Page 13: ...ignal Each mechanical instrument has its own pattern of changes in sound intensity loudness during the rise sustain and decay phases and this is a very important factor in its total characteristic tone color For instance the sound of a piano rises rapidly when a key is depressed and dies away quickly when it is released but if the damper pedal is pressed the sound will be sustained long after rele...

Page 14: ...he ring modulation effect SPEED DEPTH Sets the speed of the modulation signal Controls the maximum beat speed controlled by Attack Time Lever and Decay Tirp e Lever ATTACH TIME Controls the time span of the beat speed rising from the speed set by the SPEED lever to the maximum speed set by the DEPTH lever when a key is depressed DECAY TIME Controls the time span of the speed falling from the maxim...

Page 15: ...ntrolled by the intensity keyboard depth of keyboard depression LEVEL The deeper the key is depressed the louder the sound BRILLIANCE The deeper the key is depressed the more brilliant the sound The deeper the key is depressed the greater the effect of the sub oscillator VOLUME Controls the overall sound volume Ill PANEL 3 SUSTAIN PORTA GLTSS I ll MENTO ANDO m m r Sub Oscillator FAST 10 10 10 LONG...

Page 16: ...note proceeds smoothly in PORTAMENTO and in steps in GLISSANDO If SUSTAIN II is depressed at the same time and the key is released during the shift the interval continues to change while decaying PORTAMENTO GLISSANDO LEVER Controls the speed at which the interval changes in the portamento or the glissando IV REAR PANEL rOUTPUf r EXT HIGH CON LEl t IN LEVEL Q LOW G OUTPUT Since the synthesizer incl...

Page 17: ...ching circuit Wave shaper converter circuit Selection gate circuit of sound source wave shape Voltage controlled ftlter circuit VCF Control voltage generator VCF EG Voltage controlled amplifier circuit VCA Control voltage generator VCA EG M2 to do do M4 PRA Buffer amplifier circuit for MIX use Ring modulator circuit Expression circut Output amplifier circuit Headphone amplifier circuit SUB Sub osc...

Page 18: ...orresponding to the key voltage from the above mentioned detec tor and provides a square and sine wave as the sound source on the basis of the sawtooth by feeding the latter into a wave shaper converter The vibrato effect can be obtained by adding a manual control voltage or a modulation signaJ Jrom sub oscillator The tone color can be varied in terms of time span by applying a sawtooth or square ...

Page 19: ...S key assigner circuit board to produce the octave data by detecting to what octave the depressed note belongs On the other hand the transfer sides of the key switches for the same note in 4 blocks e g C2 C3 C4 and C5 are connected together except those of C2 The lead wires for these 12 notes from C through C plus at for the lowest note C2 which is designated as CL are linked to CL to C terminals ...

Page 20: ...or four notes are encoded and output sequentially on a timt sharing basis The ON OFF data signals of each key are also detected and produced I U4 o 1 llmu 6 TB I 7 CLo 1 Master clock oscillator 94KHz SKHz U4 octave terminals U1 c B note terminals Key data producing circuit LSI YM26600 N4 I I I Nl K04 Fig 2 Basic Construction of Key Data Producing Circuit To key Timing voltage clock detecting circu...

Page 21: ...C 24 us 5 IC Initial clear 25 Nl 6 VDD DC supply input 6 5V I 26 N2 Note code data output 4 bits 7 CL 27 N3 8 c 28 N4 9 D 29 Bl D 30 Octave code data outp lt 3 bits 10 B2 f 11 E 31 B3 12 F 32 KOI 13 p Note terminal 33 K02 14 G 34 K03 15 G 35 K04 KEY ON data output 16 A 36 K05 Note available as a pronouncing mode switching input terminal 1 A 17 37 K06 18 B 38 K07 I 19 c 39 K08 Pronouncing mode swit...

Page 22: ...5kHz Divided to 8 Repeat the 8 data D CONTROL OF PRODUCED NOTES Terminal 8 7 MODE 1 0 K08 X 1 KG 7 X X K06 X X K05tc4 X X K04 X X K03 X X K02 X X KOl X X 0 8 5V 6 5 4 0 0 0 0 0 0 1 0 0 X 1 0 X X 1 X X X X X X X X X X X X 1 6 5V 3 2 0 0 0 0 0 0 0 0 0 0 1 0 X 1 X X X X 1 0 0 0 0 0 0 0 1 X In this LSI the number of sounds note to be produced simultane ously can be varied from 1 to 8 as desired This m...

Page 23: ...tively The Key code consists of 7 bits 3 bits Bl B2 B3 for the octave code data and 4 bits Nl N2 N3 N4 for the note code data The digital data table for the keys are shown below OCTAVE CODE DATA NOTE DATA CODE Input c n n pp GG Output E A N4 1 1 1 0 0 0 I U1 U2 U3 U4 U5 t cc ccf c ccf c ccf c ccf c B3 1 1 1 0 0 N3 1 0 0 0 1 0 0 0 B2 1 0 0 1 1 N2 1 0 1 1 0 1 1 0 0 B1 0 1 0 1 0 N1 0 1 0 0 0 Table 1 ...

Page 24: ...l with this operation the octave terminal is reset from 1 to 0 which is fed into the note terminal through the depressed key switch STATE 31 As the note terminal turns to 0 this actuates the encoder to create hold and output the note data Through the operation up to STATE 3 the 7 bit key data including 3 octave bits and 4 note bits corresponding to the depressed key are created by the encoder to c...

Page 25: ...tinuously When the key of output when different octave the key in the is depressed timing same octave for 1 channel is is depressed blanked before the output of the next Since the same number of key code data as depressed are output in this timing the recurrent period may be varied key data giving preference to the key code for higher note e KEY ASSIGNER In the key assigner the key data encoded by...

Page 26: ...er Switch Turned ON Key Not Depressed When the power switch is turned ON the key code data for depressing the C4 key is automatically generated in the IC and memorized in the shift register to be shifted at the timing of the master clock pulse 94kHz and fed to the output terminals Nl through B3 as well as to Gate 2 and 12 But no key code data is supplied to 11 from the key coder unless a key is ac...

Page 27: ...w data in this channel while the data previous stored in that channel is erased When the storage 11 18 is finished Gate 1 is turned OFF and Gate 2 is turned ON to continue shifting If the key is kept depressed under this state the key on data is output through the key on off counter allowing to open the gate Keeping a Key Depressed If a key is kept depressed the key coder continuously outputs the ...

Page 28: ...e circuit is set for four note memorising As note is not stores 1 2 3 4 5 6 7 8 2 ch The data for new key is stored in the channel for the key which is just turned off KEY ON signal output for C KEY ON signal for C cleared to be output at the TR terminal 2 corresponding to the channel for 1 KEY ON signal output for C2 _____ j j keyed off sound KEY ON signal output for G ______________ 1 KEY ON sig...

Page 29: ...aring key Ba data from key I I data producing m I I circuit y As shown in fig 1 the circuit consists of 1 D A converter digital to analog 2 Glissando portamento operating circuit 3 Sample hold circuit 4 Sustain mode selector circuit fig 1 KAS circuit board PIN TERMINAL DESCRIPTION OF lSI YM26700 YM26700 20 r S I0 Juit SUSTAIN __ JS n _Select switch Kl4 IK4 M4 circuit board VCO KEY ON signal from k...

Page 30: ...ge input 35 CH4 CH8 to CH5 not used 16 OCT4 Oct5 not used 36 CH3 17 OCT4 37 CH2 18 OCT5 38 CHI 19 c 1 39 VDD DC supply input 6 5V 20 D 40 Master clock pulse ju qt TIMING CLOCK SC SC8 In this IC YM26700 is divided into 9 to produce SC clock The key code data fed from the key data producing circuit LSI YM26600 at the channel time is converted to SC channel time to detect the key voltage The period o...

Page 31: ... 11 Sample data v 1 r L_ _ hold 1 circuit PC POR Example of output C and C keys depressed C key released C4 key depressed 95 15 T 4 t umng c I I clock S I 1 I I 1 f TI0 5KHZl 1 4 8 2 3 4 Nearly held CHl term aYl 141 n _______ CH2 terminal ov 2V CH3 ten _al____ l I 2V n ____ CH4 ten al______ l J2V n_ No change __ 2 4 t fllJ IV mrlv C4 o t t t NOTE The output voltage is integrated by the subsequent ...

Page 32: ...ough ti ll hann to output the octave voltage The order is the same as that of depressing keys 3 Analog Voltage Set ladder Network for Note The octave voltage output from the D A converter is applied to the note lado I netwLwk as fundamental voltage In the note ladder network the octave voltage is divided to establish the musicu lerval for 12 notes C D D A A B C in an octave and the octave output i...

Page 33: ... D A converter the key voltage musical interval shifts sequentially stepwise The counting rate can be changed by varying the voltage applied to the PC terminal allowing to control the glissando rate the higher the voltage is the faster becomes the glissando rate 2 Integrating Gate Circuit This circuit is for obtaining the portamento effect The step voltage obtained by the glissando operation is in...

Page 34: ..._ __j The key voltage integrated in the preceding gate circuit is held only insufficiently to keep the pitch during the sustain time since the impedance of gate circuit is not high enough For this reason a sample hold circuit consisting of FET gate hold capacitor and buffer amplifier with very h1gh input impedance is provided before the VCO so as to obtain the stable key voltage DC 2 Operation of ...

Page 35: ...key assigner stores and shifts the key code data for up to four notes If all four keys are not depressed the free output channel stores the same key code data as the last depressed key In the sample hold circuit in case of Sustain I as a is at 1 b turns to 0 at the time of key ON and the output of NAND circuit turns to 1 That is the gate is opened only during key ON allowing to take the key voltag...

Page 36: ...terval frequency corresponding to the keyboard and the sound source wave shape are formed consists of voltage controlled oscillator VCO III and wave shaper converter WSC all of which are voltage controlled White noise is also used as the source signal See the section on Noise Generator PIN TERMINAL DESCRIPTION OF VCOIII IG 00153 1 Resistance terminal for transposition determination 2 Key voltage i...

Page 37: ...oltage at PIN the comparator actuates the one shot multi vibrator to deliver pulse which turns the switch ON As the switch turns ON C2 is charged by the constant current Oref and the voltage at PIN begins to rise When the output of one shot multi vibrator decays the switch turns OFF and C2 begins to discharge again These steps are repeated V pp Wave shape at PIN SW ON Wave shape fLILJL at A ttj Ti...

Page 38: ...st VR2 so that C2 is given when K 250mV VII IV Transposition v Vibrato modulation signal input Low frequency signals at 1Hz to 50Hz Adjust VR3 so that C2 is given when K 6V r ToVCF Key voltage input KEY ON 2r_j K 15 INPUT OUTPUT CHARACTERISTICS TRANSPOSITION AT NORMAL Input Voltage Output Frequency KEY voltage Frequency Interval 250mV 130 8 Hz cl 500mV 261 6 Hz c3 1V S23 2 Hz c 2V 1046 Hz c 4V 209...

Page 39: ...IN of VCO III virtually grounded thro h resistors R1 to R4 wh t ll determine octaves This circuit prevents the click noise occurred due to turning of transposition lever and stabilizes the virtual grounding When the octave switch 2 OCT DOWN is turned ON 15V applied to the terminal IV Normal is cut off to set the terminal I 2 OCT DOWN to 15V and drive the FET gate and the TR4 base positively turnin...

Page 40: ...W terminal to change the control voltage of the comparator The output pulse wave shape changes the duty ratio around that determined by the PW terminal voltage by the amount corresponding to the amplitude of and at the rate corresponding to the frequency of the low frequency signal applied to the PWM terminal Low frequency n modulation signal I To be set by voltag nur 1 I of PWM terminal 1 1 I j F...

Page 41: ...er OP1 and further amplified by a limiter amplifier OP2 up to the saturation level 30Vp p to give the white noise of constant amplitude level Control Circuit The level control circuit is a voltage controlled amplifier VCA with the gain controlled by the voltage The voltage 0 to 1OV serving as control voltage is applied to PIN 3 as input by the NOISE levervia the C terminal and controls the level o...

Page 42: ... of which cut off frequency is controlled by the voltage change is called the voltage controlled filte VCF From sound source circu Jl Sound source NOISE wave shape Voltage controlled hihg pass filter circuit VCF HPF IG00156 l5t o 1 Control voltage Voltage controlled low pass filter circuit VCF LPF IG00156 ToVCA 0_____ Tone color wave shape signal As shown in the above there are two types of VCF hi...

Page 43: ...s determined by the harmonic composition of the signal wave shape The analysis of tone color wave shape reveals that it consists of fundamentals which determine the musical interval of signal and harmonic components which have integral multiples of fundamental frequency Accordingly the tone color can be varied by changing the harmonic composition by use of the filter circuiL The f lter circuit is ...

Page 44: ... depending upon the depressed key in combination with the control voltage for the cut off frequency of VCF as the follower voltage This eliminates the following disadvantages and keeps identical tone color from the lows to the highs of the keyboard For instance if the cut off frequency of the fl lter is fixed so as to cut frequency component above 1 kHz the harmonics of A1 110Hz contain up to the ...

Page 45: ...f frequency C5 sounds for C6 sounds Cut off frequency for Cut off frequency for c4 sounds c sounds Cut off frequency for C6 sounds Filter characteristics changed by key voltage control at VCF HPF Filter characteristics changed by key voltage control at VCF LPF When the control key voltage is changed exponentially the cut off frequency is shifted in the octave relation This characteristics of VCF a...

Page 46: ...ack Level And the higher this voltage the higher the frequency will rise Decay Time Is defmed as the time taken by the cut off frequency falling from the peak level to the proper level for the depressed key Sustain Level Maintains the cut off frequency at a steady level corresponding to the depressed key as long as the key is held depressed Release Time Is defmed as the time for the cut off freque...

Page 47: ...wn resonances which critically determine the characteristic tonal color The resonance can be controlled by the voltage at the Q terrninal of VCF IC e CONSTRUCTION OF TONE COLOR CIRCUIT KEY voltage From sound source selection gate o circuit CP 2 CP 7 Q f t t fc HPF EG Q HPF1 t fdLPF fc ol The peak is controlled I0 j 1 by the resonance lever t Harmonics Emphasized 15 Q CP2 r Lo To VCA level control ...

Page 48: ...al CP4 circuit and overall CHS Envelope level level control level control r 15 G VCAl 3 C 3 IG00151l 8 3 LP2 i 1 ov V Level lever VCA2 JC5 IG00151 8 LC M Xcrrcuit R7 sheet T o e ro LEVEL g CTI o control VCA3 3 IC 6 IG00151 TP2 Check point 0 ToIl terminal of PRA circuit board VCF circuit o o VCF tone signal control VCAl CP 3 3 C 4 IG00151 LP 1 Il V VCF LEVEL lever 8 B IOOK 15 VR16 11 SL RA f f 1 0V...

Page 49: ...ried by Icont Gm K I cont K constant Q a 0 55 El u u Ci Ci 0 p V z j C 0 I Io e eo lcont The greater the control current or the control voltage the greater the gm and hence the signal level The output level changes exponentially to the voltage given to PIN 1 and also changes proportionally with the voltage given to PIN 2 OUTliNE OF VCA CIRCUIT OPERATION Input signal o 3 Controlled VR VCA circuit I...

Page 50: ...r applying the modulation signal to obtain tremolo repeat and other volume related effects Envelope voltage When synthesizing a tone color or preparing a preset tone the time dependent parameters of tone to be simulated such as rising rate peak level decay time sustain level sustain time etc may be substituted with a voltage envelope This can be manually controlled by use of a lever on the panel R...

Page 51: ...age level time course of voltage change or slope which are combined to form a voltage envelope There are two envelope generators for VCF and for VCA 6 e 81 Time vo KEY ON signa L__ J ON OFF lOl 0 o i ___ ov Time KEY ONL________l signal 15 IC s 5oK r _ _ ___ _ 42 0 r 15 15 15 B JOOK VRJS Test point l ov 8 5V 65V KEY ON signal The output of VCF EG circuit is used as the control voltage for VCF cut o...

Page 52: ...o fed into TC time control terminal through Gate 3 2 Under this condition gm of VCA is maximum with very low impedance and the capaci tor is discharged through VCA down to VIL For this reason the output of buffer amplifier is equal to VrL and fed into the seqUf nce control circuit to compare the input data DC potential to Tr terminal and keep Gate 3 ON 2 When a key is depressed the key ON data is ...

Page 53: ...he capacitor When the buffer output VB becomes equal to the sustain level voltage at Vs L this state is held until the key is released 4 When the key is released the key OFF data is fed into Tr terminal and the sequence control circuit to AL turn Gate 2 off and Gate 3 on Then VSL is lOV discharged down to V1L in a time determined by S L A L VRT OV OUTLINE OF VCA EG OPERATION To VCA circuit 2 Outwt...

Page 54: ...e other parameters A D S and R can be controlled as desired Example S sustain level lever set at high lOV J IR O A O L OV t t depress release e OUTLINE OF VCF EG OPERATION Example D decay time lever set at LONG lOV Klever set at Low Attack sounds produced ov t depress As in case of VCA envelope generator when the envelope as illustrated below is fed into the VCF circuit the cut off frequency of fi...

Page 55: ...pedal must be converted to the current The output current Io of V I converter which is based on the inverting operational amplifier is given by the following equation Io Rr Rs R3 where Vs input voltage from the expression circuit Rf Rss 100 kD and R3 820D 1 Hence Io 820 Vs Thus the output current of V I converter is proportional to the voltage controlled by the expression pedal The output current ...

Page 56: ... connected terminals 1 2 4 are connected to terminals A B C respectively to supply 15V to the lamp LED and the control voltage is output to the EI terminal through the CdS conductor 0 10 20 30 40 Tolerance 5dB dBm 0 10 30 degree 47 ...

Page 57: ... POWER switch is turned ON to lead the noise and unstable sound signal in the transient state to the ground The delay time is determined by the 47 pF 16V capacitor and 100 k Q resistor Output level Adjustment The maximum output level should be adjusted by VR6 to 0 1 dBm p p at the HO terminal and 18 3dBm p p at the LO terminal Headphone Amplifier When a headphone 8 11 load is connected this circui...

Page 58: ...ontrolled by VR7 as illustrated at the left The amplitude of the output signal is 3Vp p The principle of operation is same as that of sound source generator VCO III The VCO II contains in the IC and exponential converter which changes the linear speed control voltage into exponential voltage and a wave shape converter which changes the sawtooth wave into the sine wave In the VCO II the sine wave i...

Page 59: ...t is distinguished from the latter on the basis of fc llowing points For instance if the A3 key 440Hz is depressed and the ring modulation is made with 10Hz modulation signal signal at 7 PIN of ring modulator the output signal includes the sum and difference of two signals 450Hz and 430Hz and does not contain 440Hz input signal in contrast from the amplitude modulation of controlling the VCA with ...

Page 60: ... give the following effects 1 When the modulation signal frequency is low Llf 10Hz the difference sound 2 Llf between the two is not audible to the ear and only the changes in amplitude beating at 2 Llf can be felt giving a sort of tremolo effect Amplitude change alone audible 2 When the modulation signal frequency is high Af 10 Hz the changes in amplitude become difficult to perceive but the diff...

Page 61: ... for ring modulation The signal accepts the ring modulation by the low frequency m odulation signal to be added to the No 7 pin and is output in the No 6 pin Theoretically when one of the two signals is not input the output of RMO terminal becomes zero However the modulation signal is characterized by leakage output according to IC abberation The VRS adjusts and controls the leakage signal to less...

Page 62: ...0 Hz For the principle of operation see the section on the PWM oscillator CONTROL VOLTAGE GENERATOR To DEPTH control From K09 terminal of KAS sheet VRl Eo ATTACK TIME IT DECAY TIME DT 3 3K 8 20K 14 f In this circuit the rising and fast decaying envelope voltages are controlled on the basis of key ON signal from the KAS circuit board by use of ATTACK TIME and DECAY TIME controls and the output is f...

Page 63: ... AND TOUCH RESPONSE Touch response lever PN 2 I LEVEL Touch response Level control amplifier 00 FO To va To VCA LA terminal M1 circuit board To LC terminal M2 M4 circuit board SUB circuit board i Noise lever PN1 1 10 SUB circuit board PN3 SUB OSC lever 1 3 speed 64 ...

Page 64: ... 1 3 Hz 50 10 Hz In this circuit the VCO II frequency should be adjusted at VR7 B 500k in relation to the voltage at the VC2 terminal as shown at the left The VCO II produces the sawtooth wave in its IC and shapes it into the sine wave to be output at PIN 7 and PIN 6 respectiely b Wave Shaper Converter This circuit converts the sine wave created by the VCO II into the square wave and the sawtooth ...

Page 65: ...Auto Rhythm signal other audio signals or any other signals may be used as the modulation signal lOOK J0 25 EXO lOOK VOLUME EXT preamplifier NOTE OP IC NJM4558 These modulation signals are to be fed into VCO III VCF and VCA e TOUCH RESPONSE The touch response effect is obtained by detecting the DC voltage proportional to the strength with which the key is depressed or the depth to which the key is...

Page 66: ...canceling the mechanical failure of the shutter plate and the off set voltage of OP amplifier Reference BSOk Vi Reds BSOk x lS V BSOK voltage level gain e LEVEL CONTROL AMPLIFIER This circuit allows to control the degree of modulation by the sub oscillator signal with the key touch sui Low frequency signal from sub oscillator Touch response voltage from VCF lever 15 LoK VR4 B SOK OK 15 15 8 ____ _...

Page 67: ...age become higher or lower as the key is depressed stronger or lighter respectively The circuit is adjusted by either of VR5 or VR6 so that the input level is equal to the output level when 6V is applied to PIN 2 of each level control amplifier In the level control amplifier I VR4 is adjusted so that 0 5V centered output wave shape is obtained when OV centered input voltage is fed If the center mu...

Page 68: ...his circuit various control voltages to be fed into f1 terminal of VCF HPF and f2 terminal of VCF LPF are mixed The cut off frequency is controlled by the mixed voltage Ml Circuit M2 Circuit M3 Circuit M4 Circuit board board board board fI terminal f2 terminalf j 2 f fz J fz t t t t t t t t Input t 1 t t t t HPF LPF BRILL SUB Touch Touch tlever tlever Al JCE osc response response lever VCF VCF VCF...

Page 69: ...nals QH 1 QH 4 is 90 mV In this circuit various control voltages to be applied to LC terminal of VCA are mixed The signal level is controlled by the mixed voltage Ml circuit board LC t t SUB OSC VCA lever M2 circuit board LC t t PNl VCA M3 circuit board LC t 1 M4 circuit board LC 1 Touch response level lever LEVEL lever Reference When all the output terminals are loaded with lkS1 and all the input...

Page 70: ... PNI VCA release lever 1K release lever 15 15 To RF ter minal of VCF EG circuit on M circuit board NOTE 2is via T71 and T72 circuit boards The input voltage at SUS terminal is compared with that at 2DF or 2AO terminal and the lower voltage is output at 2FO or 2DA terminal This controls VCF EG or VCA EG circuit to set the time from the key release to the die out and the course of cut off frequency ...

Page 71: ... circuit PN2 PITCH control 4 7K VRIB B 500Q SUB circuit board VR A B IOKQ IC IC NJM4558 IYz Buffer circuit Operation The reference voltage lSV is divided by the tuning voltage circuit and the variable resistor of pitch control and the resultant volt6 is stabilized by the buffer circuit and applied to the octave voltage ladder network KAS circuit board This is the reference key voltage In this circ...

Page 72: ...uit board F A Controls for VCO VCF VCA circuits b Preset tone setting voltage divider 2 Resistor matrix T72 circuit board B c D E u v F STRING STRING2 ELECTRIC CLAVI HARPS GUITARl GUJTAR2 FUNKY FUNKY2 FUNKY3 PIANO CHORD CHORD PN2 Tone selector JOV PANEL T71 circuit board and T72 circuit board constitute the resistor voltage dividers corresponding to respective tone selectors performing similar fun...

Page 73: ... 10 7 87 2 70 8 70 4 00 3 85 7 19 10 0 5 49 4 35 4 76 6 62 8333 2 33 5 24 0 63 3 57 1 68 7 35 10 0 3 13 0 5 2417 191 10 3 33 0 4 76 7 52 2 57 10 10 4 35 10 2 17 0 63 6 41 10 4 55 0 4 55 10 2 23 7 52 10 0 10 3 33 1 28 10 6 99 8 47 0 0 0 0 0 10 0 10 2 17 0 7 35 10 f 2 50 0 43 2 94 10 5 00 10 10 0 7 52 3 85 1 64 6 41 8 33 0 0 7 52 10 2 19 7 19 10 5 24 10 0 99 0 43 8 06 6 41 0 10 6 80 10 6 68 4 76 10 ...

Page 74: ...C6 key is depressed and C3 261 6 Hz 1 cent when C2 key is depressed Repeat these steps a few times To check the correspondence of depressed key to M circuit board touch VR2 on one of M circuit board while the sound is produced If the musical interval is modulated by hum the M circuit board under check is producing the sound 4 Similarly setting the transposition lever to NORMAL VI terminal15V adjus...

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Page 77: ...SINCE1887 YAMAHA NIPPON GAKKI CO LTD HAMAMATSU JAPAN 006362 Printed in Japan K S SOSHISHA 19772 10 ...

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