ProTone_MIDI_Analog_Synth_Service_Manual 电路图.pdf

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1、 Service Manual ProTone Page 1 of 20 1996-2001 Spectral Audio ProTone MIDI Analog Synthesizer Service Manual Copyright 1996-2001 by Spectral Audio, Switzerland CAUTION! All instructions in this manual must be carried out by a professional who observes the valid safety regulations. In operation, they

2、 have got dangerous voltages in the instrument. Spectral Audio GmbH accepts no liability for personal injury or material damage. RadioFans.CN 收音机爱 好者资料库 Service Manual ProTone Page 2 of 20 1996-2001 Spectral Audio 1 Description of the Operating Elements 3 1.1 Sockets on the Rear of the Housing 3 1.2

3、 Front Panel Controls 4 2 Functional Description 5 3 History of Series 7 4 Improvements and explanations 7 4.1 Sense of R174 and R175 7 4.2 Sense of C63 C65 7 4.3 Sense of R174 and R175 8 4.4 Hum Problems 8 4.5 Increasing the Gate voltage to +12V 8 5 Adjustment of the ProTone 9 5.1 Digital PCB (MIDI

4、 to CV converter) 9 5.2 Analog PCB (VCO1 and VCO 2) 9 5.2.1 VCO1 9 5.2.2 VCO2 9 6 Digital PCB 11 6.1 Assembly plan 11 6.2 Part list 11 7 Analog PCB 13 7.1 Assembly plan 13 7.2 Part list 15 8 Mechanical part list 20 RadioFans.CN 收音机爱 好者资料库 Service Manual ProTone Page 3 of 20 1996-2001 Spectral Audio

5、1 Description of the Operating Elements Out Left Out Right Extern VCO Input Extern LFO Input GateCVMIDI Thru MIDI IN 0.7 Veff 0.7 Veff 0V:Off 1V/Oct 5V:On 230 V max. 500mAT ProTone Made in Switzerland 373638394041424344 Warning : Shock Hazard - do not open! Vorsicht : Lebensgefahr - nicht ffnen! Avi

6、s : Risque de choc Electrique - ne pas ouvrir! SPECTRAL AUDIO GmbH Serial No. 1.1 Sockets on the Rear of the Housing 36. Power socket 37. Fuse compartment, fuse max. 500 mA, 250V type 38. Audio outputs right / left 39. External VCO input, switched on with switch (7) 40. External modulation input, se

7、lected with selector switch (22) 41. Gate input/output (dependent on the jumper setting inside the unit, standard setting: output) 42. CV input / output (dependent on the jumper setting inside the unit, standard setting: output) 43. MIDI Thru socket 44. MIDI IN socket RadioFans.CN 收音机爱 好者资料库 Service

8、 Manual ProTone Page 4 of 20 1996-2001 Spectral Audio TUNEPW NOISE TUNE SLIDE EXT VCO 1 VCO 2 FILTER KEY- FOLLOW LFO FREQUENCYMODULATION WAVE LFO ON . NOISE EXT. PW 1 VCO 1 VCO 2 PAN RANDOM RANGE MIDDLE LOW HIGH ProTone GATE / LEARN POWER GROUND- LEVEL LEARN PAN ENV MOD CUTOFFRESONANZ VOL VCO 2 RING

9、MOD VOL VCO 1 DECAYATTACKSUSTAINRELEASE CUT OFF ACCENT 24 dB HIGHPASS LOWPASS 12 dB SYNC ON MIDI ANALOG SYNTHESIZER - 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 65 4 2 1 12 3 0 78 9 10 11 65 4 2 1 12 3 0

10、 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 6 5 4 2 1 12 3 0 78 9 10 11 C1 RL 5 4 3 2 5 1 4 32 01 66 5 4 3 2

11、 5 1 4 32 -+ 01 66 5 4 3 2 5 1 4 32 -+ 1 0 123 4567 8911 1410 12131819 151617252627 2021222324 282931 30 32 33 3435 SPECTRAL AUDIO 1.2 Front Panel Controls VCO 1: 1. TUNE: Regulates the pitch of the VCO 1 2. PW: Pulse width of the rectangular pulse 3. Changeover between the signal types saw tooth, n

12、oise and rectangle 4. SLIDE: regulates the time balance of VCO 1 and VCO 2 VCO 2: 5. TUNE: Regulates the pitch of the VCO 2 6. SYNC: Synchronises VCO 2 with VCO 1 7. Changeover between the signal types saw tooth, external (input on rear of housing) and rectangle Mixer: 8. VOL VCO 1: Volume of VCO 1

13、9. RINGMOD: Volume of the ring modulation of VCO1 and VCO2 10. VOL VCO 2: Volume of VCO 2 VCF: 11. CUTOFF: Cut-off frequency of the filter 12. RESONANCE: increases the harmonics at the cut-off point 13. Changeover between lowpass and highpass 14. ACCENT: Pulsed increase of the cut-off frequency and

14、the volume 15. ACCENT ON Indicator: Lights when the accent function is switched on (MIDI Controller 65) 16. Determines the edge steepness of the filter: 12 or 24dB / octave 17. KEYFOLLOW: The cut-off frequency is influenced by the actual note LFO: 18. RANGE: Changeover between three LFO frequency ra

15、nges 19. FREQUENCY: Setting the LFO frequency 20. LFO Indicator: Indicates each positive half wave of the LFO. Note: The eye recognises frequencies larger than 60 Hz as being static. 21. Changeover between symmetrical and asymmetrical LFO waveforms 22. Selector switch for different LFO waveforms. By

16、 means of the matrix presentation, there are a total of 9 signal forms available: sinus, asymmetrical sinus, triangle, saw tooth, rectangle, pulse, random, noise and external (input on the rear of the housing) 23. MODULATION: Determines the strength of the LFO influence 24. LFO ON.: LFO assignment p

17、ossibilities: VCO 1, VCO 2, PW 1, cut-off, pan (any combination possible) Envelope: 25. ATTACK: Rise time 26. DECAY: Decay time 27. SUSTAIN: Hold level 28. RELEASE: Release time 29. ENV MOD: Influences the cut-off frequency with the envelope Stereo VCA: 30. GROUNDLEVEL: Ground level of the unit. Thi

18、s also includes the volume increase influenced by the accent. 31. PAN: Regulates the relationship of the volume from the left and right-hand channel Various: 32. LEARN Key; Switches the ProTone to the learn mode 33. GATE / LEARN indicator 34. Switch-on indicator 35. Main switch Service Manual ProTon

19、e Page 5 of 20 1996-2001 Spectral Audio 2 Functional Description The basic principle of the ProTone corresponds to the tried and tested analog synthesizer principle with VCO, VCF, VCA, envelope generator and LFO. This principle is called subtractive synthesis. In order that the ProTone is suitable f

20、or MIDI, an additional MIDI to CV converter is necessary which converts the MIDI signals into analog signals with which the VCOs, the filter, as well as the envelope generator are controlled. The raw material for the sound is offered by the VCOs (Voltage Controlled Oscillator) in the form of a sawto

21、oth or rectangular signal as well as the noise generator (for effects such as wind and thunder sounds). The width of the rectangular signal from VCO1 can be changed with the PW regulator (2). The narrower the rectangular signal (regulator turned to the right), the sharper the sound. VCO2 is synchron

22、ised from VCO1 with the SYNC switch (6). The tone will be interesting in this case when the TUNE regulator (5) of VCO2 is turned (or by modulating with the LFO VCO 2), which results in a typical Sync-Sound. By means of the external VCO input, other sounds can also serve as raw material. The ring mod

23、ulator multiplies the signals of the two VCOs which markedly amplifies the beat (frequency difference). Note: When the SYNC switch (6) is switched on, no beats are developed and the ring modulator has therefore no effect. The SLIDE regulator (4) determines the time balance from one note to another a

24、nd is valid for both VCOs. Afterwards, the signal flows through the voltage controlled filter (VCF=Voltage Controlled Filter), within which certain frequency ranges are suppressed. The lowpass filter allows low frequencies to pass and suppresses the high ones, the highpass filter lets high frequenci

25、es through and suppresses the low ones. The frequency from which the signals are suppressed is called the limit or cut-off frequency. With the ProTone, this is formed from various sources: 1. CUTOFF frequency regulator (11) 2. ENV MOD regulator (29) (influence of the envelope on the cut-off frequenc

26、y) 3. LFO 4. ACCENT regulator (14) 5. KEYFOLLOW switch (17). With the KEYFOLLOW switch (17), the cut-off frequency increases on higher notes so that audible frequency bands always remain the same. The resonance forms a feedback of the output to the input of the filter and causes an amplification of

27、the frequencies around the cut-off frequency. The ACCENT regulator (14) sets the share of the second envelope and affects the cut-off frequency as well as the volume. It is only active when the ACCENT indicator (15) lights, i.e., when the accent function is switched on via the MIDI controller 65. Th

28、e accent function is always active when the unit is switched on. By means of the MIDI controller 65, it is now possible, as with the TB 303, to give individual notes an accent (value 127) or to take an accent away (value 0). For this purpose, the corresponding control value must be sent in the seque

29、ncer, timed either before or with the note. Before the signal leaves the ProTone, it arrives at the VCA (Voltage Controlled Amplifier) which is available in the ProTone in stereo form. Here the input signal is multiplied with a control signal. In this way, the volume can be influenced by a control s

30、ignal which comes from the envelope generator and the MIDI converter. The volume of the ProTone is controlled with the GROUND LEVEL regulator (30) as well as via the MIDI controller EXT (7). Additional to this level is the short-term increase through the accent function. The panorama (volume relatio

31、nship of the left-hand to the right-hand signal) can be set with the PAN regulator (31). The LFO is particularly developed with the ProTone. Using its signal, the pitch from VCO1 and VCO2, the pulse width of the rectangular signal from VCO1, the cut-off frequency of the filter as well as the panoram

32、a can be modulated with the LFO ON . switches (24). With switches (21) and (22) selection can be made between 9 different signal forms. By means of the external LFO input on the rear of the housing, it is also possible to use any other signal for modulation. To do this, switch (22) must be turned co

33、mpletely to the right. A microphone, etc, must be connected via a pre-amplifier as this is a high level input. When the external inputs of the ProTone are used, the ProTone must simultaneously receive a note command (the same MIDI channel) in order that something is audible. The envelope generator d

34、etermines the chronological sequence of the volume after receiving a note command. The MIDI to CV converter then gives out a gate signal (+5V) with which the sequence of the envelope generator begins. The gate signal remains at +5V until the note off command comes, i.e., the key is Service Manual Pr

35、oTone Page 6 of 20 1996-2001 Spectral Audio released. The parameters of the envelope can be set with regulators (25) to (28). How the envelope should be imagined is described later on in the glossary. Service Manual ProTone Page 7 of 20 1996-2001 Spectral Audio 3 History of Series There where 3 diff

36、erent series made: Serie # 1 : 960000 . 960020 with golden front panel Serie # 2 : 960021 . 960161 with red front panel, C66 and C67 added Serie # 3 : 960162 . 960470 with red front panel, now with switch and trafo for 115V / 230V; R173, R174, C63-C65 inbuilt; R174 and R175 (NTCs) added (by hand); G

37、ND Connection to case This manual describe the last serie. This manual contains no the hole schematics. Spectral Audio may send it to you for important reasons, please write to infospectralaudio.ch. 4 Improvements and explanations 4.1 Sense of R174 and R175 These two resistors helps to increase the

38、lower limit of the cutoff frequency. Otherwise a ploop- noise may occur when reaching 0 Hz cutoff frequency with a high resonance. You may reach the 0Hz using the LFO. They are in serie connected from U20 pin 16 to GND. 4.2 Sense of C63 C65 With time, the pots may become noisy. You may hear this eff

39、ect especially at the Cutoff pot. Using the C63 C65 solve this problem. They are connected from the middle pin (+) of the pot to GND (-). Resonance has negative voltage, so middle pin is (-) and GND is (+): Service Manual ProTone Page 8 of 20 1996-2001 Spectral Audio 4.3 Sense of R174 and R175 These

40、 NTC resistors improves the temperature stability of the two VCOs a lot. It is important that, if you add these NTCs, also change the resistors R81 and R86 to 5k1. Use hot glue to glue them onto U16. Sold them parallel to R81 and R86: After this change, a readjustment must be done. 4.4 Hum Problems

41、In some circumstances, the internal connection from GND to the metal case creates a hum noise because of closed earth loops. In this case it may help to cut this internal GND connection. You will find it (on later Protons series only) on the digital pcb, a pretty wide track to one screw. Cut it with

42、 a sharp cutter. 4.5 Increasing the Gate voltage to +12V To increase the Gate voltage from +5V to +12V, two additional resistors and one NPN transistor are necessary. Apart from this, port 1.3 (pin 4) of the microprocessor must be connected to GND that the gate signal output from the microprocessor

43、is inverted. The circuit change appears as follows: Service Manual ProTone Page 9 of 20 1996-2001 Spectral Audio 5 Adjustment of the ProTone 5.1 Digital PCB (MIDI to CV converter) The slope of the control voltage CV is set with trimmer R10. Octave jumps which are initiated via MIDI-IN, must result i

44、n a 1.00 V change. For this purpose, an accurate voltmeter must be connected to the CV socket J3 and the reference note (default: 36=C1) initiated and the voltage value noted (some mV). Now initiate the MIDI note four octaves higher (C4) and adjust R10 so that the voltage is 4.00 V higher. Check the

45、 reference note again and repeat the adjustment if necessary. 5.2 Analog PCB (VCO1 and VCO 2) In order to tune the VCOs, the analog PCB must first be separated from the front panel (6 screws with spacers). The analog PCB must then be reconnected to the digital PCB and started. After disassembly, the

46、 Tune VCO1 and Tune VCO2 knobs must be replaced and positioned exactly in the centre (Tune setting = 0). Before adjustment, the unit should be in operation for approximately one hour. The adjustment should be made at room temperature. Before adjusting the VCO, check the CV slope (chapter above). The

47、 setting of R10 in the MIDI to CV converter is valid for both VCO of course. 5.2.1 VCO1 The frequency of the oscillator can be taken from pin 8 of U11 or at the unit output, whereby the filter must be open and set to Lowpass. Only VCO1 must be audible (set the mixer correctly). Make sure that no LFO

48、 modulation take place. The offset for VCO1 is set with R21 and the slope with R157. Nonlinearity in the upper frequency range is adjusted with R29. Proceed as follows to make the adjustment: 1. Set trimmers R21, R157 and R29 to the base settings shown below. 2. Set the ProTone MIDI reference note t

49、o C1 by pressing the learn-key. 3. Press key A3 and set the VCO1 frequency with R21 to 220.00 Hz, measured with an exactly frequency meter. 4. Press key A1 and set the frequency to 55.00 Hz with R157. 5. Repeat steps 3 and 4 until frequency values are stable. 6. Press the key A5 and set the frequency to 880.0 Hz with R29. 7. Repeat steps 3 to 6 and re-adjust if