Plum OCP User manual

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
1
OCP is Ornament and Crime PLUS
Updated trough hole version of Ornament and Crime
Ornament and Crime - Polymorphic cv generator is one of the most versatile cv
generator / processor module for Eurorack.
Ornament and Crime can load dozens of different apps for many uses, If this is your
first Ornament and Crime - you will going to love this module and you will always find
creative ways to use it in any of your following patches.
Official Firmware or Alternative Firmware:
There are two firmware versions available: Official firmware and Hemisphere suite,
OCP kits comes pre loaded with the official firmware but it is an easy task to switch
between firmware versions if you wish, more details here.

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
2
PLUS?
OCP is slightly different from other Ornament and Crime versions, few
improvements are added to OCP:
VOR –Variable Outputs Range make it easy to select different offsets for the
outputs (Bi-Polar, Uni-Polar and Asymmetric), with the official firmware the module
automatically choose the best offset for each application and you can always change
it with the dedicated VOR button.
Extended Range –OCP outputs can deliver 10v peak to peak.
Front USB Input –Can be used for accessing easily to MIDI to CV / CV to MIDI
functions of the Hemisphere firmware (Captain MIDI).
Atenuverters –With the 4 knobs you can scale and invert any modulation source
you plugged to the CV inputs, when nothing plugged in, those knobs connected to
internal voltage source and can control many parameters of each application.
Trough Hole Design –OCP uses mostly through hole component (kits are with pre
soldered SMD DAC and Supervisor chips).
OCP Full DIY Kit:
Inside the kit you will find all the needed parts to complete your OCP.
Use this instruction guide step-by-step and check your work in each step.
OCP contain 175 components with total of 679 solder points, take your time, do it
patiently, and take breaks when you feel tired or not focused.
I filmed the build process and the videos are integrated within this document, you
can also access the full playlist here.
For any questions that arise, feel free to seek help from our community, here

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
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There are several steps in the assembly process:
1. Main Board assembling
2. UI Board assembling
3. Connecting boards together
4. Interface parts and panel assembling
5. Calibration
You will need those tools for the assembling process:
1. Soldering Iron and high quality soldering wire
2. DMM - Multimeter
3. Cutter
4. Plier
5. Paper masking tape
6. Computer or mobile device with web browser and internet connection to
access iBom.
* Tip about soldering iron tips:
There are many soldering iron tips (heads) that used for different kinds of
soldering jobs, In fact, you can do all types of soldering with one conical (cone)
tip and get to beautiful solder points, but I definitely recommend using the types
of tips that are appropriate for the soldering nature.
This is to make the solder faster and get better solder points.
For this project I’ll recommend to use 2 types of soldering iron tips :
conical tip (at 360o-430oc) for most of the parts in this
project, The sharper the edge, the higher the
temperature.
Knife tip (at 300o-360oc) for pin headers and IC
sockets, with this tip you can hit up 2-3 pins simultaneity
and solder long row of pins in one continuous drag (my
favorite tip!)

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
4
BOM (Bill of Materials):
For your convenience, all component values are printed on the boards, use iBom
to easily find the component locations on the boards, you can access iBom with
any browser on your computer or your mobile device.
Main Board iBom
UI Board iBom
* How to use iBom:
iBom is abbreviation for Interactive Bill Of Materials, an online system that is
used as a live map of the board and components.
Use iBom table to look for components on the board, you just need to hover a
mouse on one of the table lines to highlight the elements on the board live map.
When you're done solder each line, mark this line as "Placed" so you will see
your progress anytime.
When you first open the iBom, I recommend changing the settings a bit (view
picture below).
For Main Board set the view for the back of the board (B)
and board rotation to -180o
For UI Board set the view for the front of the board (F)
and board rotation to -180o
For higher contrast it’s probably better to use Dark mode.
These settings will be automatically saved at your browser cookies so that the
next time you open the page, it will display exactly how you left it.

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
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*About my favorite soldering technique:
After many years of soldering electronic circuits I have found that I prefer to solder
most of the through hole components from the side where the components are
(when possible, especially resistors) with a sharp conical tip.
In this method I can see the component at the moment of soldering, I can work on
flat surface without helping hands and I succeed to get beautiful soldering points that
works 100% of the time.
If you have already adopted a preferred soldering method use it, you are of course
welcome to watch my method in the attached videos and try it.
STEP 1 –MAIN BOARD ASSEMBLING:
The most efficient way is to assemble the components according to their height on
the board, so it is advisable to start with the lowest components and move to the
higher components.
Solder components at this order:
Watch Video
1. Resistors and Inductor:
Inside the components bag you will find 3 bags with all the resistors needed
for the Main board:
Bag 1: 100R, 100K, 10K and 10uH Inductor
Bag 2: 220R, 1K, 2K
Bag 3: 24K, 33K, 75K
*How to identify resistor value?
The resistors inside the kit are arranged in strips, you just have to count the number
of resistors in each strip and cross with the number written on the bag label to know
what the value is. But it's always a good idea to make sure the value is right, for that
you can use your DMM to measure the resistors in each strip or use the color coding
of the resistors, you can use this color code calculator.
2. Diodes –Polarity is mandatory, the line on the diode should match with the
line that printed on board
1N5819 to D1, D2
3. IC’s sockets for IC6, IC7, IC8, IC9, IC10
The orientations of the sockets are not really matter but IC's
orientation is mandatory!
I’ll recommend to solder the sockets at the same orientation
that printed on the board In order to avoid confusion when
assembling the IC’s, In general –in both OCP boards
horizontal IC's are facing left and verticals IC's are facing up.
do not connect the IC’s to the sockets at this stage.
* Paper masking tape can help you to hold the sockets in their
places before you flip the board to solder them on the bottom
side.

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
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4. MLCC (Multilayer ceramic capacitors) - Inside the components bag you will
find one bag with all the main board MLCC, polarity doesn't matter:
22pF, 560pF, 100nF, 470nF, 1uF
* How to identify MLCC value?
The 3 digits that is printed on the capacitor is the value code in pF, the 2
first digits are the significant figures of the value and the third digit
indicates how many zeros the multiplier has (0 = multiplier is 1 without
zeros, 1=10, 2=100, 3=1000 and so on…).
it’s mean that:
on 22pf the printed code is 220 (22pF X 1),
on 560pF the code is 561 (56pF X 10),
on 100nF the code is 104 (10pF X 10,000),
on 470nF the code is 474 (47pF X 10,000)
and on 1uF the code is 105 (10pF X 100,000).
5. Transistors –Orientation is mandatory - the flat side should be directed as
indicated on the board.
2N3904 to Q1, Q2, Q3, Q4
6. Regulators –Orientation is mandatory
IC1, IC2, IC3, IC5
7. Tantalum and Electrolytic Capacitors - Polarity is mandatory, longer leg
should go to the hole with the + sign.
8. Power header (IDC Connector) Polarity is mandatory, the cut-out of the
socket should face down.

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
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9. Teensy board –Inside the kit you will
find the teensy board and rows of 14,
13 and 2 pin headers, the male
headers is already attached to the
female sockets, don’t separate them.
The side of female sockets should
soldered to the Main board and the pin
headers to the teensy board.
Insert all sockets to the holes in the
main board, place the teensy board on
top of the pin headers and first solder the pins to the teensy.
then you can solder the female headers to the main board from the other side.
Watch Video
10. POGO Pins –or spring-loaded pins, used
to connect 3 pads from the teensy board to the
main board.
one pin is for reset and other two is to connect
the USB data signals (D+ and D-).
first you need to remove the teensy from his
socket. Insert the pins to the holes (spring end
should face up) and solder them from the other
side of the board.
Hurray!
You're done with the main board for now, it's time to start with the UI board.
If you feel you need a rest you should do it now and return to the assembly process
when you feel refreshed.

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
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STEP 2 –UI BOARD ASSEMBLING:
Take the UI board out from the antistatic bag and open the UI iBom, Solder the
components at the following order.
Watch Video
1. Resistors:
Inside the components bag you will find 2 bags with all the resistors needed
for the UI board:
Bag 1: 510R, 10K, 100K
Bag 2: 100.0K
Pay attention to 16 X 100.0K in the second bag, those are accurate resistors
with tolerance of 0.1%, Don't mix them with the other 100K resistors otherwise
the attenuverters zero point will be out of center.
2. IC’s sockets for IC1, IC2
3. MLCC –22pF, 100nF, 470nF
STEP 3 –CONNECTING BOARDS TOGOTHER:
Start with screwing the metal standoff to the UI board, insert the
screw from components side to the hole in the board, then insert the
plastic washer to the screw from the other side and tight the
standoff on the screw.
Inside the kit you will find one rows of 19 pins, two rows of 6 pins
and one row of 2X10 pins, the male headers is already attached to
the female sockets, don’t separate them.
Place the UI board on flat surface with the components side facing
down, place all headers in place, the female sockets should be
soldered to the UI board.
Place the the main board on
top of the headers with components side
facing up, make sure all headers in their
places.
attach the second screw to the other side of
the standoff to hold the boards together.
now you can solder all pins from both side.
Watch Video

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
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STEP 4 –INTERFACE PARTS AND PANEL:
For the next steps, please separate the boards, we going to assembling all interface
parts to the UI board.
Except the OLED Screen do not solder the interface parts before you attach the
panel.
1. OLED Screen assembling:
Inside the kit you will find a small bag with the OLED, 3 standoffs and 1X7
pin header.
First screw the 3 standoffs to the main board to support the screen, insert
1X7 pin headers to the holes in the UI board.
Place the screen on top of the standoffs, make sure that the pin headers in
their places from both sides and tight the top 2 screws.
now you can solder the pin headers from both sides.
Watch Video
2. USB Input:
Prepare the USB board by soldering the USB jack to the small USB board
and the pin headers to the bottom side of this board.
Place the USB board in his place on the main board, don’t solder it yet.
Watch Video
3. LEDs:
Inside the kit you will find a bag of bipolar LEDs.
These LEDs should light green when the voltage is positive and red when
the voltage is negative.
Please note:
Some OCP kits are provided with LEDs which need be mounted
reversed from the printed on the board, so the supplied LEDs must
first be checked.
Use the black LED tubes provided in the kit, which will allow the
installation of the LEDs at the right height and provide support and
insulation for the LED legs.
Place the LEDs in their holes and bend the legs in the other side, do not
solder them yet.
You can solder the LEDs only after you check if they light the correct
colors (do it as the last assembly step):
- Top row of LEDs should light Green when attenuators fully clockwise.
- Outputs LEDs should light Red when the module is powered and the
default app is activated (ASR app in official firmware).

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
10
4. Push Buttons:
Inside the kit you will find 2 push buttons with a
white caps.
Although they will work even if you install them in
reverse polarity for the sake of interface
correctness you should install them in the correct
polarity.
the buttons have two modes: pressed and un-
pressed, the un-pressed state should indicate
bipolar operation of the attenuverters and the
pressed state will indicate unipolar operation.
At the bottom of the button there is a minus mark on one side, this mark
should be directed to the left.
Insert the buttons to the holes in the board but do not solder yet.
5. Jacks, Encoders, Tall Trimmers, Tact switches:
There is no special instructions for the rest of the interface parts, attach
them to the board but do not solder yet.
6. Install 2 IC’s (TL074) on the IC’s socket, make sure the polarity is correct
(pin 1 mark should face left).
7. After all UI parts are in place attach the panel and tight all jack nuts and
encoder nuts.
8. Use paper masking tape to hold buttons and LEDs in place and solder all
parts except the USB board.
9. Before you solder the USB board, connect a micro USB cable to the jack
(leave the other end unconnected), push the pin headers of the USB board
against the cable and make sure the jack align with the panel.
10.Hurray, you're almost done!
Do not forget to assemble all IC’s to the sockets.

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
11
STEP 5 –CALIBRATION:
Before you can use your new OCP it is very important to calibrate it.
The calibration lets you fine-tune the CV outputs and inputs as well adjust some
basic settings.
The calibration procedure of OCP is similar to any other Ornament and Crime
version but there are few differences to be aware, in this document I will review the
calibration of OCP in highlights, to read about the calibration procedure in depth
please refer to Ornament and Crime manual here.
Watch Video
To enter to the calibration mode keep push down the left encoder during startup.
1. Encoder directions:
With the encoders that supplied with the kit, the left encoder will be in reverse
direction, to fix it –press twice on “up” button (the button bellow left encoder).
2. Use default values:
Yes! It is new module that has never calibrated before…
3. Correct display offset:
With the OLED provided there should be no offset problems, you can skip to
the next step.
4. CV Outputs:
In the following 40 steps you will calibrate the CV outputs from the most left
out (A) to the most right out (D), 10 calibration points for each output - 0v to
10v.
5. VOR:
The next 2 steps are used to calibrate the 2 extra offset modes of the cv
outputs (VOR), first step is for the bi-polar mode and second for the
asymmetrical mode.
In both steps you need to calibrate to closest you can get to 0v.
since VOR system is using the internal DAC of the Teensy (less accurate then
the main DAC) precision of +/-0.0015v is fine.
6. CV Inputs:
To calibrate the CV Inputs 0v first turn all attenuverters knobs fully clockwise
and insert patch cable to each cv input you calibrate, leave the other end
unconnected.
to calibrate CV in 1 to 1v and 3v connect the other and to one of the outputs.
7. Screensaver timeout period:
Here you can set. the timeout period before the screensaver is activated, the
default value is 25 seconds, if you preferer longer or shorter time you can
configure it now.
8. Save? Yes!!! 

Plum Audio
OCP rev 1.2 - Build Guide v1.2
10.07.20
www.plum-audio.com
12
You're done!
Check your new OCP and read Ornament and Crime firmware manual to understand
how to operate it.
If you have problems, questions or if you found mistakes in this document visit
PlumAudio DIY First Aid group at Facebook to get help or to contact me.
With Love,
Shay Shezifi,
Plum Audio