Updated : dec. 7th, 2008 CV/GATE Mono Keyboard controler
En français 
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Description



Schematics







Printed circuit boards and component layouts

NOTE : the PCB and a component kit for this module are now made available by Bridechamber
8 by 8 matrix scanner PCB

Component layout






Get the schematic as a PDF file
Get the PCB as a PDF file


Building details

8 by 8 scanning matrix (Fatar keybed)
reference
value
quantity
U1,U2
CD4051
2
U3
PIC16F88 or PIC16F84A** 1
U4
TLC7524 1
U5
LM358 or TL072
1
U6
7812 or 78L12 regulator
1
U7
7805 or 78L05 regulator 1
U8
7912 or 79L12 regulator 1
R1,R2
10 ohms 5%
2
R8,R10*,R11*,R15*,R16*,R20*,R21*,R25*,R26*
220 ohms * matched to 1%
5% otherwise
9
R7,R9*,R14*,R19*,R24*,R42,R46
1k * matched to 1%
5% otherwise
7
R12*,R13*,R17*,R18*,R22*,R23*,R27*,R28*,
R29,R35,R36,R37,R38,R43
10k * matched to 1%
5% otherwise
14
R44
15k 5%
1
R40,R41
27k 5%
2
R45
33k 5%
1
R3,R4,R5,R6,R30,R31,R32,R34,R39
100k 5%
9
R33
150k
1
C3,C4,C5,C6
470p matched to 1%
4
C7,C8
100n
2
C1,C2,C9,C10
22µF 35V
4
T2
2k2 10 turns trimmer
1
T1
47k 10 turns trimmer
1
P1,P2
47k log potentiometer
2
P13,P4,P5,P6
47k lin potentiomter
4
Jk1,Jk2,Jk3,Jk4,Jk5,Jk6
female jack sockets
6
Wiring



Front panel
Panel design


silkscreening and drilling


Download the silkscreen mask as a PDF file

Download the silkscreen mask as a JPEG file



Trimming

V/Octave tracking :
  • Turn the frequency knob to 0, turn all the control knobs to 0 (fully counter clockwise)
  • Apply 0V to the V/Oct input
  • Measure the voltage at the basis of Q6 (2SA798) (node between R46, R30 to R34), adjust T1 in order to obtain 0V at this very node.
  • Apply 1V to the V/Oct input
  • Adjust T2 in order to measure 18.7mV at the previous node.
  • Apply 0V to the V/Oct input
  • Adjust T1 in order to measure -187mV at this very node.

Frequency range setting :

  • Apply a 40Hz squarewave to one of the audio input, connect the output to an amplifier.
  • Set the FREQUENCY potentiometer to 0 (fully counter clockwise)
  • Adjust T1 until no signal can be heard at the output, that's it !

Optional settings

  • If you wish to change the range of the resonance potentiometer change the value of R44, increasing its resistance will reduce the resonance range, reducing the resistance will increase the auto-oscillating behaviour at maximum resonance.
  • If you wish to keep the original ARP resonance behaviour suppress R43



References

Here are interesting links where to find schematics and infos about the ARP VCF :
  • ARPTECH, the old Joachim Verghese's site
  • Analog Metropolis ,
  • EFM kits, VCF7b
The DIY builders' gallery
Here are the photographs of the yusynth ARP modules built by other synth geeks around the world.
Thank you  guys for sending me these nice photos.




















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