Assembly Instructions

   available in french, too. Thanks to Egnouf for translating!

This page provides you with all information necessary to assemble your kit.
Please read and follow the instructions carefully. Even if you are just a few hours away from playing with your new synth, don't work in a hurry. A stupid mistake will take longer to fix than to take your time and work thoroughly.

If you have one of the early batch 1 PCBs (revision 0.4) please continue reading here.

 

Pitfalls - Read First!!!

There are a few points to consider before starting your build.

  • The R_LED resistors don't need to be populated. Only R7 needs a 220 ohm resistor, the others can be left unpopulated. There are some old pictures from the previous version in the instructions that still show the R_LED resistors in place. They are now replaced with the resistor networks.
  • Solder the display and its connector last! The correct order is: Midi jacks, display connector pin header to PCB from top, then the display onto the connector. Any other order will NOT result in a successful build!

  • Solder the 7805 voltage regulator with the heatsink attached, to guarantee the correct distance to the PCB!

 

Bill of Materials

The BOM for the project can be found here.

 

Schematics

The schematics for the frontpanel are available as a PDF here,
The schematics for the mainboard here.

 

Preparations

Tools you'll need:

  • Soldering iron
    something like the
    ERSA TIP 260 is sufficient

  • Soldering iron stand
    for example
    this one

  • Solder
    use thin solder, 1mm or less. Something like
    this. Do not use the thick plumbing solder!
    For beginners solder containing lead is recommended.

  • Wire cutter

  • Solder sucker
    not essential if you do everything right, but very handy if you have to desolder anything.

  • Multimeter

  • screwdriver

  •  a 2.1mm DC wallwart power supply (7-9V DC, center pin positive, at least 600mA ).

  • some electrical tape (Isolierband)

It is assumed that you already know how to solder. If you never soldered before, we strongly recommend you to solder a small and cheap kit first to learn the basic skills.
Curious Inventor have a nice soldering guide available here.

 

 

Disclaimer

We are not responsible for any assembly related failures such as non working kits due to build errors, accidents involving electricity and/or hot soldering irons and not even angry family members due to excessive soldering sessions.

 

Lets start!

Power up your soldering iron, put on some nice music or your favourite radio show and enjoy the build!

 

Bottom of the PCB

We start on the bottom of the board. There you will find the power supply and the MIDI circuitry, as well as all the conectors to the outside world.

 

Step 1 – Resistors

All parts with a part number beginning with R are resistors.
Resistors don't have a polarity, so it doesn't matter which way around you solder them in.

 

Image

Description

Amount

Part nr.

Notes



 

221 Ohm resistor

3

R1 – R3

 


1k2 resistor

1

R4

 



 

5k6 resistor

1

R5

 

not populated

Only needed if you have a custom LCD instead of the OLED provided with the kit. Value depends on the LCD type.

0

R51

Only for LCD users! Controls the backlight brightness.

 

Step 2 – Diodes

Part numbers starting with a 'D' are diodes. Unlike the resistors, the diodes are polarized!
 

Image

Description

Amount

Part nr.

Notes



 

1N4001 diode

 

Function: reverse polarity protection if a wrong PSU is attached to the DC jack.

 

 

1

D1

Polarized part!

Silver ring.



 

1N4148

 

 

Function: protection diode for the optocoupler input

1

D2

Polarized part!

Black ring

 

  • One side of the diode is marked with a ring around its body. This ring can also be found on the silkscreen as a line. The ring for both diodes should face away from the MIDI connectors.



 

Step 3 – Capacitors

All the capacitor part numbers start with a 'C'.
The kit uses different kinds of capacitors. The electrolytic ones are polarized.

Image

Description

Amount

Part nr.

Notes



 

Electrolytic capacitor
220uF

 

 

 

Function: smoothing capacitors for the PSU

2

C1, C3

Polarized part!

The shorter leg is negative, the longer leg is for the positive voltage.

Electrolytic capacitor
100uF

 

Function: smoothing capacitor for the SD-card power supply.

1 C23  



 

 

100nF ceramic capacitor

 

 

Function: smoothing capacitors for the PSU

2

C2, C4

 

  • solder the 220uF and 100nF caps for the PSU. Watch out for the polarity of the two 220uF caps! The short leg goes into the round pad.
    The 100nF caps are not polarized. Insert them either way.



 

  • solder the 100uF cap below the mainboard connector P1. Once again, this is a polarized part. Short leg to round pad.

 

Step 4 – Voltage regulator and DC jack

Image

Description

Amount

Part nr.

Notes



 

 

Heat sink for the voltage regulator

 

1

 

 



 

 

M3 screw

 

1

 

 



 

 

7805 voltage regulator

 

 

Function: takes an unregulated input voltage and makes it a stable 5V voltage.

 

1

U1

Do not solder without attached heatsink!



 

DC jack

1

 

 



 

IC socket DIP 8

1

OK1

Notch has to be the same direction as the print on the PCB

Bridge 1 - This is just a normal piece of wire. use one of the cut off resistor legs from the previous steps.

 

  • Start by soldering the bridge to position 'S33'. You can use one of the cut off resistor legs from the previous steps. If you like to use a power switch for your build (not included in the kit) you have to attach your switch instead.

  • Solder the DC jack.

  • Attach the heatsink to the voltage regulator using the M3 screw.

 

 

 

 

 

 

 

 

 

  • Solder the voltage regulator. The side with the heatsink has to face the DC jack.

 

  • Solder the IC socket. Do not yet put any IC inside the socket. Align the notch of the socket with the notch on the PCB silkscreen.



 

Step 5 – Time for a first test

Congratulations! You just finished soldering the 5V PSU of your new drum machine. Now is a good time to test if it is working.

  • Attach your power supply to the DC jack (7-9V DC, center pin positive, at least 600mA@7.5V ).

  • Use your multimeter to measure the voltage between pin 5 (GND) and pin 8 (+5V) of the IC socket 'OK1'

  • Your multimeter should show about +5V



 



 

Troubleshooting – My multimeter does not show 5V

  • 4.9V or 5.1V is ok, too!

  • If it shows -5V you just mixed up the test points (red and black probe switched)

  • Is the wire bridge on position S33 soldered?

  • Is the diode orientation correct? (both rings point away from the midi jacks)

  • Is the electrolytic capacitor polarity correct?

  • Is your power supply polarity correct?

  • Is the orientation of the 7805 correct? It should not get hot at this point!

  • If nothing works, head over to the forum. Do not continue your build if the PSU is not working!

 

 

Step 6 – Connectors

As a last step we will solder all the connectors but the USB jack to the bottom of the PCB.

 

Image

Description

Amount

Part nr.

Notes



 

MIDI jacks

2

P2, P3

 



 

Audio Jacks

4

J2, J3, J4, J5

 



 

Female 2x13 header, 2.54mm

2

P1, P2

 

USB jack type B

1    

not populated

Contrast trimmer 10k
only needed if you use a custom display instead of the OLED provided with the kit.

1

VR1

Only for LCD users!

 

 

  • solder the female connectors P1 and P2. Make sure they are completely flat on the PCB!  If they are not, you may have trouble installing the mainbaord later on.
    It may be easier to install them completely flat, if you attach them to the mainboard for soldering. This ensures that the mainboard will fit once the connectors are soldered.

 

  • solder the audio jacks

 

  • Next are the MIDI jacks. Solder the center pin first, then align the jack flat on PCB and solder the rest.

  • Cut away the pins on the top of the PCB as short as possible, so that later on in the build the display can lay flat on the other side of the PCB.



 

  • Now solder the USB jack

 

Top of the PCB

After finishing the bottom, we will now assemble the top of the PCB.
If you like you can already add the 4 metal stand offs to the 4 corners of the board. This makes working on the board easier.



 

Step 7 – Resistor networks

Image

Description

Amount

Part nr.

Notes

10k resistor network
9 pin, common gnd

 

Function: These are pull-down resistors to GND for the switches.

5    

220ohm resistor network
9 pin, common gnd

 

Function: These are current limiting resistor for the  LEDs

5  

These are current limiting resistor for the  LEDs. If you are using other LEDs than provided with the kit, you have to change their value accordingly.

 

  • Solder the 10k resistor networks.The GND pin is marked by a dot.The pin with the dot has to be soldered into the pad marked with a square around it.

 

  • Next, solder the 220 ohm networks. As before, the dotted side goes tothe square.

 

Step 8 – Capacitors

There are only ceramic type capacitors used on the top of the PCB. They are non polarized and can be inserted in either direction.

Image

Description

Amount

Part nr.

Notes



 

Ceramic 100nF

 

 

Function: decoupling caps

15

C8-C22

 



 

Ceramic 47nF

 

 

Function: Ensures the power supply rail has stabilized before booting the AVR

1

C7

 



 

Ceramic 22pF

 

 

Function: part of the 20MHz quartz oscillator

2

C5, C6

 

 

  • Solder the 47nF and the 22pF capacitors next to the atmega644 footprint.

 

  • The 100nF caps are next.

Step 9 – Quartz and Inductance

Image

Description

Amount

Part nr.

Notes



 

Inductance 10uH

 

 

 

Function: part of an LC-filter to cancel noise in the ADC for the potentiometers

1

L1

 



 

Quartz 20MHz

 

 

 

Function: generates the clock for the AVR

1

X1

 

 

  • Solder the quartz and the inductance. Both parts are non polarized.

 

Step 10 – IC sockets

Now it's time to solder all IC sockets.
 

Image

Description

Amount

Part nr.

Notes



 

IC socket DIP40

1

IC1

Notch has to be the same direction as the print on the PCB



 

IC socket DIP16

11

U2-U7,

U9-U13

Notch has to be the same direction as the print on the PCB

 

  • Attention! The notch on the DIP40 socket points in a different direction than on the other sockets



The notch direction is marked with a dot on this image

Step 11 – Resistors

Image Description Amount Part nr. Notes



 

10k resistor

7 R6, R8, R9, R26, R60, R64, R91

 



 

221 ohm LED resistor

 

 

Function: current limiting resistor for the copy LED

1

R7

R7 is a current limiting resistor for the copy LED. If you are using other LEDs than provided with the kit, you have to change its value accordingly.

  • Solder R7. It is marked as "R_LED" on the screenprint. The other "R_LED" positions are left blank.

  • Solder the10k resistors

 

 

Step 12 – Switches

 

Image

Description

Amount

Part nr.

Notes



 

TL1100 tactile switch

39

S1-S32,

S34-S40

 

 

  • Put all the switches on the PCB. They should snap in and stay in place. Be sure that all switches lay flat on the PCB before soldering.

 

  • Be sure to double check if you soldered all switches. It's very easy to forget some pins.

 

Step 13 – LEDs

The LEDs are polarized parts! The longer leg is the positive (+), the shorter the negative (-) side.

Image

Description

Amount

Part nr.

Notes

Green LED

21

 

polarized

Red LED

2

 

polarized

Orange LED

4

 

polarized

Yellow LED

12

 

polarized

 

  • For all LEDs on the board, the longer leg has to be inserted into the upper hole.



 

 


Step 14 – Display connector

This part is a little bit tricky. You already soldered the MIDI jacks to the bottom of the PCB in step 6. Since they are blocking the way, you can not solder the display connector like you normally would. You have to solder the pin array from the top.

Image

Description

Amount

Part nr.

Notes



 

Pin header male, 1x16, 2.54mm

1

L1

 

 

  • Insert the pin array upside down. That means the longer side of the pins goes into the holes on the PCB. Since the MIDI jacks are right below, you won't be able to insert them very deep.

 

  • Now you have a gap between the PCB and the black plastic thingy holding the pin array together. Here you need to apply your solder. Solder a single pin first, then adjust the pin array to point straight up and solder the rest of the pins with as little solder as possible.

 

  • Take a screwdriver or similar and push the black plastic thingy down in the direction of the PCB. You cannot push it down in one go. You have to push alternating left and right to slowly move it down.

 

  • If you took too much solder to push the plastic part down, either try to remove it using a solder sucker/wick, or remove the plastic part completely.

 

Step 15 – Encoder and Potentiometers

Add the 4 potentiometers and the encoder to the PCB.

Image

Description

Amount

Part nr.

Notes



 

Encoder + switch
24 clicks, 25mm shaft

1

ENC1

 



 

10k potentiometer, linear

4

 

 

 

  • Solder one pin first and make sure the parts are flat on the PCB. Then solder the rest of the pins.



 

 

Step 16 – The end is near! A last voltage test

Before inserting all the ICs, we will make sure the voltage is correct and nothing is shorted on the power rails.

  • If you have a multimeter with Continuity tester (it makes *beep* when the 2 probes touch) check that there is no continuity between the two marked points. A short beep in the beginning of the measurement is ok. That's caused by the charging capacitors.

If you have continuity between those points you have to recheck your soldering! It means you have a short between the 5V and the GND rails that could damage your synth and power supply when both are connected. DO NOT CONTINUE UNTIL THERE IS NO CONTINUITY BETWEEN THOSE 2 PINS!



 

  • Attach power supply to the DC jack

  • Measure voltage between the 2 points

 

  • You should read around 5V

 

  • Remove power supply

 

Step 17 – Attach the standoffs

 

Image

Description

Amount

Part nr.

Notes



 

Standoff 10mm

4

 

 



 

Standoff 30mm

13

 

 



 

M3 screw

9

 

 

 

  • Add the standoffs to the board. A M3 screw on top of the board, a 30mm spacer on the bottom. The 9 positions are marked in the following picture.



 

  • If you have not attached the 4 standoffs in the corners of the board, do it now. The 10mm spacers on top, the 30mm standoffs on the bottom.

 

Step 18 – Insert all ICs

The ICs are polarized. One side of the ICs is marked with a notch. When inserting the ICs, line up the notch on the IC with the notch of the socket/silkscreen. On the upper side of the PCB the notch of all ICs is either pointed to the right side of the board or up. Only the atmega is faced to the left. On the bottom the notch/dot should face away from the MIDI jacks.

Image

Description

Amount

Part nr.

Notes



 

Atmega644p, 20MHz

 

 

 

Function: microcontroller to run the user interface software

1

IC1

Notch faces other direction than all other ICs!



 

74HC4050 Hex buffer

 

 

 

Function: used as voltage converter to reduce the 5V signals from the AVR to 3V3 signals for the SD card.

1

U4

Must be the HC version!



 

74HC595

 

 

Function: serial-in/paralell-out shift register. Used to adress all LEDs from just a few AVR pins

5

U3, U7, U9, U11, U13

 

 



 

74HC165

 

 

Function: paralell-in/serial-out shift register. Used to read all buttons with just a few AVR pins

5

U2, U5, U6, U10, U12

 

 



 

6N138

 

 

Function: optocoupler for the MIDI input. Keeps the GND of the different MIDI devices separate.

1

OK1

Located on the bottom.

Dot instead of notch.

 

  • Even if you have all standoffs attached, it is recommended to support the PCB from the back with your fingers while pushing the ICs in from the top. Do not bend the PCB!

  • Insert the Atmega644p. Attention! The notch on this chip has to face to the left.

  • Insert the 74hc165 ICs



 

  • Insert the 74hc595 chips

  • Insert the 74HC4050

  • Insert the 6n138 (bottom of the PCB)

 

Step 19 – Powering up again

Just to be sure – power up the device after inserting all the ICs.

Touch the ICs with your fingers. None of them should get hot.

remove power supply.

 

Step 20 – Attach mainboard and test

Now we are going to test if everything is working, so we can solder the display to the device.

Image

Description

Part nr.

Notes



 

STM32F4 audio mainboard

 

 

 

Function: This board holds the STM32F4 ARM processor which runs all of the DSP code to generate the audio signals. There are also 2 audio codecs wich provide the digital to analogue conversion.

 

 

 

  • Attach the mainboard to the 2 female connectors on the bottom of the PCB



 

  • Power up the device

  • Wait until the green 'voice mode' LED is lit.

 

  • Press the 'start' button

 

  • The LED next to the start button should start flashing
  • The chaselight should start running

 

Troubleshooting: No blinkenlights :(

  • Check chip orientation

  • Do you have a programmed atmega? (you have if you bought a kit)

  • Is the mainboard attached correctly

 

Step 21 – Solder Display

Now it's save to assume everything is ok and you can finally attach the display.

Image

Description

Part nr.

Notes



 

2x16 OLED display

 

 

 

  • Put the display on the 1x16 pin header. Make sure to cut off the legs of all the parts below as short as possible, so that the display sits flat on the PCB. Then solder the display to the connector from the top.

 

  • if you connect the power supply again, your display should show:

 

  • Only for LCD users: adjust contrast trimmer if your display does not show anything

 

Step 22 – Button Caps

Image

Description

Part nr.

Notes



 

19 x black cap

 

 



 

6 x grey cap

 

 



 

2 x red cap

 

 



 

12 x white cap

 

 

1 x Plasticine glue (Blu Tack)

(Added to the kit april 2014)

   

 

  • Make a thin roll out of the plasticine

 

  • Cut the roll into 39 little pieces (the so called "Huskerballs"), one for each button cap

 

  • Put one of the pieces on the bottom of every cap

 

  • now put the caps on the buttons



 

Congratulations! You are now the proud owner of a Sonic Potions drumsynthesizer!
I hope you enjoyed the build and have fun with your new synth!

 

Step 23 – SD Card Image

Before you start, please prepare your SD card.

  • Unzip all files to the root folder of your (FAT32!) SD card

 

Quickstart Guide

The fastest way to get some beats out of your new box!

  • Insert SD card and power up the synth.

  • Press start button. The chaselight starts running.

  • Use the 16 step buttons to activate some steps. Now you should hear something.

  • Use the 7 voice select buttons to change the active track/voice.

  • Again, use the 16 step buttons to activate some steps. The 2nd voice should play now as well.

  • Press the red load/save mode button once. You are now in preset load mode.

  • Use the encoder to select another preset. The sound should change as soon as you move the encoder.