Majella audio Velocity Voltage Controlled Amplifier Diy Manual

The Majella audio Velocity Voltage Controlled Amplifier is a DIY kit designed for building a eurorack module. This module provides velocity-sensitive control over audio signals, making it ideal for creating dynamic and expressive sounds. The kit includes all necessary components, including a PCB, panel, and electrical components. You will need basic soldering tools and a digital multimeter to complete the assembly.

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VVCA DIY MANUAL
Version 1.0
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
INTRODUCTION
1. The VVCA
The VVCA kit is a small DIY kit. This kit is
suitable for DIY’ers who have their basic
soldering skills under control. The kit is
designed to be as easy as possible.
2. Requirements
The Kit contains the PCB, Panel and all
electrical components to finish the module.
You will need (as a bear minimum): basic
soldering tools and a Digital multimeter to
finish this module.
Required tools:
•
•
•
•
•
Soldering iron/station
Soldering tin
Wire cutter
Multimeter
Nut driver (plier, at own risk )
3. Bill of materials (BOM)
To start, it is good practice to check if the kit
is complete. We double check the kitbags,
but we are human (tududududuuuhduuh)
after all.
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&copy;2018 Majella Audio
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
22R Resistors (2x)
First we start with the 22R restistors. There
are two of them (R49, R50). They are placed
on the yellow markings in the figure 1.
Figure 1:
(YELLOW )
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22R
resistor
placem ent
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
1K Resistors (7x)
Now that the 22R resistors are soldered we
can go on with the 1K resistors.
There are 7 resistors with a 1K value (R2, R12,
R14, R16, R22, R25, R32).
Their placement is shown in figure 2. They
are marked yellow. The blue resistors
represent the already soldered resistors:
Figure 2:
(YELLOW )
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1K
resistor
placem ent.
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
10K Resistors (16x)
The next resistors to solder are the 10K
resistors. There are 16 of them that need to
be soldered (R4, R5, R6, R7, R13, R15, R18,
R19, R23, R24, R27, R28, R33, R34, R37, R38).
Figure 3:
(YELLOW )
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10K
resistor
Placem ent
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
100K Resistors (8x)
Now we are going to do the 100K resistors.
There are 8 of them. (R3, R8, R17, R20, R26,
R29, R36, R39) Figure 4 shows their position
(yellow) on the PCB. Lets go champ!
Figure 4:
(YELLOW )
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100K
resistor
placem ent
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
220K Resistors (4x)
You should now be getting tired of
soldering resistors, but we are almost there!
Just four of these 220K resistors. (R1, R10,
R11, R31). They are yellow marked in figure 5.
Figure 5:
220K
(YELLOW ).
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&copy;2018 Majella Audio
resistor
placem ent
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
330K Resistors (4x)
The last 4 resistors! These are gonna be the
330K (R9, R21, R30, R40). Figure 6 shows
where they need to be placed.
Figure 6:
(YELLOW )
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330K
resistor
placem ent
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
IC sockets 16 pin (2x)
For the LM13700’s we need to solder 2 IC
sockets. There are 2 IC sockets with 16 pins
on the PCB. Check the notch for
correct orientation!
Figure 7:
16
pin
placem ent (YELLO W )
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&copy;2018 Majella Audio
IC
socket
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
IC sockets 14 pin (1x)
Now we need to solder the 14 pin IC socket
for the TL074 opamp. Check the notch
for correct orientation!
Figure 8:
14
pin
placem ent (YELLO W )
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&copy;2018 Majella Audio
IC
socket
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
100nF capacitors (6x)
The are 6 capacitors on this board. Their
placement is marked yellow.
Figure 9:
100nF
placem ent (YELLO W )
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&copy;2018 Majella Audio
capacitors
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
NPN transistors 2N3906 (4x)
The are 4 yellow marked PNP transistors on
the PCB. We now need to solder these. Do
not solder these the other way around!!
Check the belly for the orientation (figure
10).
Figure 10: 2N3906
placem ent (YELLO W )
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&copy;2018 Majella Audio
Transistor
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
Power connector (1x)
To connect this module to your eurorack
system we will need to solder a 16 pin IDC
connector. Notice the orientation of the
connector (figure 11)!
Figure 11: Pow er
placem ent (YELLO W )
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connector
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
3.5 mm minijack connectors (8x)
Solder the 8 minijack connectors on the
PCB. We use these so you can include the
VVCA in your patch cable spaghetti! The
placement of the jacks is marked yellow in
firure 12.
Figure 12:
(YELLOW )
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3.5
mm
jack
placem ent
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
22uF Capacitors (3x)
Almost done! We need to solder 3
electrolytic capacitors on the PCB. See
figure 12 for their placement. Note their
orientation, They will explode if not
correctly placed, no joke!!
The positive (+) side can be recognized by
the longer leg. The negative side (-) is
marked by a yellow/gold strip with the –
sign on it. The negative side is marked
purple in figure 12.
Figure 12: 22uF
placem ent (YELLO W )
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capacitors
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
IC placement
You can turn off your soldering iron! You will
only need to place the IC’s in their sockets!
Note the orientation of the IC’s!.
PCB is done!
Figure 12:
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IC placem ent
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
Final check + panel
First check if the IC’s and the
capacitors are orientated correctly.
22uF
Now place the panel on to the jack
connectors and put on the Hex nuts, DONE!
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VVCA Velocity Voltage Controlled Amplifier
DIY Manual
Bill of materials:
Qty
Value
Device
Parts
R4, R5, R6, R7, R13, R15, R18, R19, R23, R24, R27, R28,
R33, R34, R37, R38
16
10k
Resistor
7
8
6
2
4
3
4
4
2
1
1
1k
100k
100n
22R
220k
22uF
2N3906
330k
LM13600AN
TL074P
N/A
Resistor
Resistor
Ceramic Capacitor
Resistor
Resistor
electrolytic capacitors
PNP transistor
Resistor
LM13600AN
TL074P
IDC Socket
8
1
2
1
1
N/A
N/A
N/A
N/A
Amazing
Jack 3.5mm
IC Socket
IC Socket
Ribbon Cable
Cookie
R2, R12, R14, R16, R22, R25, R32
R3, R8, R17, R20, R26, R29, R36, R39
C1, C2, C3, C4, C5, C6
R49, R50
R1, R10, R11, R31
C7, C9, C10
T1, T2, T3, T4
R9, R21, R30, R40
IC1, IC3
IC6
X2
CV_IN, CV_IN_2, INPUT, INPUT_2, OUTPUT, OUTPUT_2,
VELOCITY, VELOCITY_2
N/A
N/A
N/A
Stroopwafel
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&copy;2018 Majella Audio
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
Thanks for your patience and soldering skills!
Enjoy your VVCA!
VVCA DIY Manual
version 1.0
08-2018
&copy;2018
https://majella-audio.com
[email protected]
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&copy;2018 Majella Audio
VVCA Velocity Voltage Controlled Amplifier
DIY Manual
Designed and made in Holland
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&copy;2018 Majella Audio
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Key features

Eurorack compatibility
Velocity-sensitive control
Dual channel input & output
DIY assembly
LM13700 op-amps for audio processing
TL074 op-amp for control voltage processing
22uF electrolytic capacitors for filtering
100nF ceramic capacitors for decoupling
1k, 10k, 100k, 220k & 330k resistors

Frequently asked questions

You will need a soldering iron/station, soldering tin, wire cutter, multimeter, and a nut driver (plier can be used, but with caution).

The VVCA utilizes two LM13700AN op-amps for audio processing and one TL074P op-amp for control voltage processing.

The positive (+) side of the capacitor is indicated by the longer leg. The negative (-) side is marked by a yellow/gold strip with a minus sign. Ensure correct orientation, as improper placement can result in damage.