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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
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12
C13 C14
CON1
D1 D2 D3 D4 D5 D6
D7 D8
J1 J2 J3 J4 J5 J6 J7 J8 J9
PCB_CON1_1 PCB_CON2_1
PCB_CON1_2 PCB_CON2_2
Pcv1 Pcv2
Pofs1 Pofs2
Q1 Q2
R1 R2 R3 R4 R5 R6 R7 R8 R10 R12 R16 R17
R19 R20 R37 R38 R39 R40 R41
R21 R22 R29 R31 R47 R48
R23 R24 R27 R28
R25 R26 R30 R32
R42 R43 R44
R45 R46
R9 R11 R13 R14 R15 R18 R33 R34 R35 R36
SW1 SW2
TRbal1 TRbal2
TRgain1 TRgain2
U1 U2 U3
U4
U5
U1 U2 U3
U4
U5
Calibration instructions can be found on the last page.
12
100nF
2
10uF
1
IDC 10-pin
6
1N4148
2
1N5818
9
3.5mm jack
2
8 pin header male
2
8 pin header female PCB connector PCB2 (1x8 pin)
2
100k
2
22k
2
BC557B
19
100k
6
10k
4
22k
4
470R
3
1k
2
10R
10
200k
2
on-off-on
2
50R
2
50k
3
TL074
1
LM13700
1
TL072
3
DIP14
1
DIP16
1
DIP8
2
4
1
1
Capacitor bypass MLCC X7R 2.5-
2.54mm pin pitch
Capacitor electrolyte 2mm pin pitch,
5mm dia, max 10mm height. Min 25V.
IDC 10 pin power connector (2x5 pin)
Signal diode
Schottky diode (or 1N5817, 1N5819)
Thonkiconn 3.5mm jack socket
PCB connector PCB1 (1x8 pin)
Linear Pot Alpha/Song Huei 9mm
Linear Pot Alpha/Song Huei 9mm 20-25k
PNP transistor
Resistor 1/4W 1% ca 7mm long
Resistor 1/4W 1% ca 7mm long
Resistor 1/4W 1% ca 7mm long
Resistor 1/4W 1% ca 7mm long
Resistor 1/4W 1% ca 7mm long
Resistor 1/4W 1 to 5% ca 7mm long
Resistor 1/4W 1% ca 7mm long
SPDT on-off-on mini toggle switch.
Mouser# 108-1MS3T2B3M2QE-EVX
Trimpot Bourns 3296W or equivalent
Trimpot Bourns 3296W or equivalent
DIP-14 quad op-amp (or TL084)
DIP-16 dual OTA
DIP-8 dual op-amp (or TL082)
IC Socket
IC Socket
IC Socket
PCB spacer 11mm
Knobs
16 to 10 pin IDC ribbon cable
Panel
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Summary of Contents for LJUNGGREN 2xVCX
- Page 1 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 Capacitor bypass MLCC X7R 2.5- C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 100nF 2.54mm pin pitch...
- Page 2 PCB pictures PCB1 PCB2...
- Page 3 Assembly instructions We start with PCB2. Step 1 Solder small signal diodes. Diodes 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.
- Page 4 R23, R24, R27, R28 22K 4pcs R25, R26, R30, R32 470R 4pcs R45, R46 10R 2pcs...
- Page 5 R9, R11, R13, R14, R15, R18, R33, R34, R35, R36 200k 10pcs Step 3 Solder power polarity 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.
- Page 6 Step 5 Solder IC sockets. 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. U2, U3 14 pin DIP sockets (DIP-14) IC's will be mounted later. 2pcs U4 16 pin DIP socket (DIP-16) 1pcs Step 6 Solder electrolytic capacitors.
- Page 7 Step 8 Flip PCB2 to the bottom side. Solder the power header. Make sure the key opening is oriented in the same way as in the 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.
- Page 8 Step 10 Insert the ICs in the sockets. If you feel the least uncertain on the IC direction, please search 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.
- Page 9 Step 12 Solder ceramic capacitors. Ceramic capacitors are not sensitive to mounting direction. C1, C2, C7, 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.
- Page 10 Step 14 Mount the spacers with the nuts on PCB1. You can have the screw-side on PCB1 as well if you feel that it's more comfortable. Step 15 Put the pin & socket strips into each other. Place them between PCB1 and PCB2 in their respective places.
- Page 11 Step 16 Cut off the small metal tab sticking out on the potentiometers. Use a cheap plier/nipper for this step, save your expensive ones for other tasks. Mount 1 washer and 1 nut on each potentiometer. Make sure the nuts are tight. Sometimes we ship the kits with Alpha potentiometers and they are cleasly marked with "Alpha".
- Page 12 Step 18 Place the front panel on top and add 1 washer and 1 nut to each potentiometer and jack, 1 nut to the switches. Use a socket wrench to avoid scratching of the frontplate. The switches have big pad holes to allow more different switches to fit but it also means you need to be extra careful to make sure the switch is aligned straight.
- Page 13 Cablibration For best result, let the module warm up with power on for 20-30 minutes before calibration. Use either your hearing or an oscilloscope. 1) Patch an unconnected cable to 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% +.