Majella audio Velocity Voltage Controlled Amplifier User manual

VVCA DIY MANUAL
Version 1.0

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
2
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.

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
3
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: 22R resistor placement
(YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
4
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: 1K resistor placement.
(YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
5
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: 10K resistor Placement
(YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
6
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: 100K resistor placement
(YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
7
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 resistor placement
(YELLOW).

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
8
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: 330K resistor placement
(YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
9
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 IC socket
placement (YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
10
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 IC socket
placement (YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
11
100nF capacitors (6x)
The are 6 capacitors on this board. Their
placement is marked yellow.
Figure 9: 100nF capacitors
placement (YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
12
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 Transistor
placement (YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
13
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: Power connector
placement (YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
14
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: 3.5 mm jack placement
(YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
15
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 capacitors
placement (YELLOW)

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
16
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: IC placement

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
17
Final check + panel
First check if the IC’s and the 22uF
capacitors are orientated correctly.
Now place the panel on to the jack
connectors and put on the Hex nuts, DONE!

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
18
Bill$of$materials:$
$
$
Qty$
Value$
Device$
Parts$
16$
10k$
Resistor$
R4,$R5,$R6,$R7,$R13,$R15,$R18,$R19,$R23,$R24,$R27,$R28,$
R33,$R34,$R37,$R38$
7$
1k$
Resistor$
R2,$R12,$R14,$R16,$R22,$R25,$R32$
8$
100k$
Resistor$
R3,$R8,$R17,$R20,$R26,$R29,$R36,$R39$
6$
100n$
Ceramic$Capacitor$$
C1,$C2,$C3,$C4,$C5,$C6$
2$
22R$
Resistor$
R49,$R50$
4$
220k$
Resistor$
R1,$R10,$R11,$R31$
3$
22uF$
electrolytic$capacitors$
C7,$C9,$C10$
4$
2N3906$
PNP$transistor$$
T1,$T2,$T3,$T4$
4$
330k$
Resistor$
R9,$R21,$R30,$R40$
2$
LM13600AN$
LM13600AN$
IC1,$IC3$
1$
TL074P$
TL074P$
IC6$
1$
N/A$
IDC$Socket$$
X2$
8$
N/A$
Jack$3.5mm$
CV_IN,$CV_IN_2,$INPUT,$INPUT_2,$OUTPUT,$OUTPUT_2,$
VELOCITY,$VELOCITY_2$
1$
N/A$
IC$Socket$$
N/A$
2$
N/A$
IC$Socket$$
N/A$
1$
N/A$
Ribbon$Cable$
N/A$
1$
Amazing$
Cookie$$
Stroopwafel$$

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
19
Thanks for your patience and soldering skills!
Enjoy your VVCA!
VVCA DIY Manual
version 1.0
08-2018
©2018
https://majella-audio.com
[e-mail]

VVCA Velocity Voltage Controlled Amplifier
DIY Manual
©2018 Majella Audio
20
Designed and made in Holland