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Produced by:

Roll Your Own

ljunggrenaudio.com

Schematic & PCB Design by:

KYMATICA DEVICES
www.kymatica.com

2xVCX

 version 1.0

 

Bills Of Material   Bold = PCB1

Calibration instructions can be found on the last page.

12

100nF

C13 C14 

2

10uF

CON1 

1

IDC 10-pin

IDC 10 pin power connector (2x5 pin)

D1 D2 D3 D4 D5 D6 

6

1N4148

Signal diode

D7 D8 

2

1N5818

Schottky diode (or 1N5817, 1N5819)

J1 J2 J3 J4 J5 J6 J7 J8 J9 

9

3.5mm jack

Thonkiconn 3.5mm jack socket

PCB_CON1_1 PCB_CON2_1 

2

8 pin header male

PCB connector PCB1 (1x8 pin)

PCB_CON1_2 PCB_CON2_2 

2

8 pin header female PCB connector PCB2 (1x8 pin)

Pcv1 Pcv2 

2

100k

Linear Pot Alpha/Song Huei 9mm

Pofs1 Pofs2 

2

22k

Linear Pot Alpha/Song Huei 9mm 20-25k

Q1 Q2 

2

BC557B

PNP transistor

19

100k

Resistor 1/4W 1% ca 7mm long

R21 R22 R29 R31 R47 R48 

6

10k

Resistor 1/4W 1% ca 7mm long

R23 R24 R27 R28 

4

22k

Resistor 1/4W 1% ca 7mm long

R25 R26 R30 R32 

4

470R

Resistor 1/4W 1% ca 7mm long

R42 R43 R44 

3

1k

Resistor 1/4W 1% ca 7mm long

R45 R46 

2

10R

Resistor 1/4W 1 to 5% ca 7mm long

R9 R11 R13 R14 R15 R18 R33 R34 R35 R36

10

200k

Resistor 1/4W 1% ca 7mm long

SW1 SW2 

2

on-off-on

TRbal1 TRbal2 

2

50R

Trimpot Bourns 3296W or equivalent

TRgain1 TRgain2 

2

50k

Trimpot Bourns 3296W or equivalent

3

TL074

DIP-14 quad op-amp (or TL084)

U4 

1

LM13700

DIP-16 dual OTA

1

TL072

DIP-8 dual op-amp (or TL082)

3

DIP14

IC Socket

U4 

1

DIP16

IC Socket

1

DIP8

IC Socket

2

PCB spacer 11mm

4

Knobs

1

16 to 10 pin IDC ribbon cable

1

Panel

C1 C2

 C3 C4 C5 C6 

C7 C8

 C9 C10 C11 C12

Capacitor bypass MLCC X7R 2.5-
2.54mm pin pitch
Capacitor electrolyte 2mm pin pitch, 
5mm dia, max 10mm height. Min 25V.

R1 R2 R3 R4 R5 R6 R7 R8

 R10 R12 R16 R17 

R19 R20 

R37 R38 R39 R40 R41

 

SPDT on-off-on mini toggle switch. 
Mouser# 108-1MS3T2B3M2QE-EVX

U1

 U2 U3 

U5

 

U1

 U2 U3 

U5

 

Summary of Contents for 2xVCX

Page 1: ... R48 6 10k Resistor 1 4W 1 ca 7mm long R23 R24 R27 R28 4 22k Resistor 1 4W 1 ca 7mm long R25 R26 R30 R32 4 470R Resistor 1 4W 1 ca 7mm long R42 R43 R44 3 1k Resistor 1 4W 1 ca 7mm long R45 R46 2 10R Resistor 1 4W 1 to 5 ca 7mm long R9 R11 R13 R14 R15 R18 R33 R34 R35 R36 10 200k Resistor 1 4W 1 ca 7mm long SW1 SW2 2 on off on TRbal1 TRbal2 2 50R Trimpot Bourns 3296W or equivalent TRgain1 TRgain2 2 ...

Page 2: ...PCB pictures PCB1 PCB2 ...

Page 3: ...des are sensitive to mounting direction make sure the stripe on the diode match the stripe on the silkscreen D1 D2 D3 D4 D5 D6 1N4148 6pcs Step 2 Solder resistors Resistors are not sensitive to mounting direction R10 R12 R16 R17 R19 R20 100K 6pcs R21 R22 R29 R31 R47 R48 10K 6pcs ...

Page 4: ...R23 R24 R27 R28 22K 4pcs R25 R26 R30 R32 470R 4pcs R45 R46 10R 2pcs ...

Page 5: ...y protection diodes Diodes are sensitive to mounting direction make sure the stripe on the diode match the stripe on the silkscreen D7 D8 1N5818 2pcs Step 4 Solder ceramic capacitors Ceramic capacitors are not sensitive to mounting direction C3 C4 C5 C6 C9 C10 C11 C12 100nF 8pcs ...

Page 6: ... U4 16 pin DIP socket DIP 16 1pcs Step 6 Solder electrolytic capacitors Electrolytic capacitors are sensitive to mounting direction Put the long pin in the hole marked with a anode on the silkscreen The opposite side cathode is marked with fully filled silkscreen C13 C14 10µF 2pcs Step 7 Solder transistors transistors are sensitive to mounting direction Match the curved side on the transistor with...

Page 7: ... picture below It s easier to avoid bent pins if you attach the power cable in the header while you are soldering CON1 2x5pin Step 9 Flip PCB2 to the bottom side Now it s time to solder trimmers They are not sensitive to mounting direction TRbal1 TRbal2 50R multi turn trimmer 2pcs TRgain1 TRgain2 50k multi turn trimmer 2pcs ...

Page 8: ...the web for IC orientation U2 U3 TL074 TL084 2pcs U4 LM13700 1pcs Leave PCB2 on the side with the PCB to PCB connectors not soldered Now it s time for PCB1 Step 11 Solder resistors Resistors are not sensitive to mounting direction R1 R2 R3 R4 R5 R6 R7 R8 R37 R38 R39 R40 R41 100k 13pcs R42 R43 R44 1k 3pcs ...

Page 9: ... C8 100nF 4pcs Step 13 Solder IC sockets and insert IC s Match the IC sockets indent marking pin 1 side with the silk screens If you feel the least uncertain on the IC direction please search the web for IC orientation U1 14 pin DIP socket DIP 14 U5 8 pin DIP socket DIP 8 U1 TL074 TL084 U5 TL072 TL082 ...

Page 10: ...mfortable Step 15 Put the pin socket strips into each other Place them between PCB1 and PCB2 in their respective places Take a firm grip with a plier around the spacers and screw the screws into place If the nuts gets loose tighten them again Remove them again after the pin socket strips are soldered Solder the connectors ...

Page 11: ... potentiometer Make sure the nuts are tight Sometimes we ship the kits with Alpha potentiometers and they are cleasly marked with Alpha In that case you don t need any washer or nut under the panel Step 17 Place potentiometers jacks and switches in their positions but wait with soldering until the front panel is mounted You will need to bend the ground pins a little bit on the jacks ...

Page 12: ...ake sure the switch is aligned straight The switches have their own nuts Make sure to keep them separate from the jacks nuts as they look very similar and the switch nuts will fit on the jacks but the jack nuts won t fit on the switches Now you solder all panel components in place Step 19 Now attach PCB2 to the module and screw the spacers together like in step 14 15 Remember the firm grip with th...

Page 13: ... the A1 input 2 Set the toggle at the right B A position turn OFFSET 1 knob to 0 and CV attenuator 1 knob to 100 3 Patch VCO to CV1 input and adjust TRbal1 for minimum CV feed through on OUT1 4 Move VCO patch cable to B1 input turn OFFSET knob to 100 and adjust TRgain for minimal amplitude on OUT 5 Repeat until satisfaction Do the same for the second channel 2 Finished module ...

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