This build is an intermediate level build, not recommended for absolute beginners. If you are a beginner, it is recommended that you do an easier build before starting this project.
Note that the development board (Adafruit Itsybitsy RP2040) used in this module comes pre-programmed when purchased from Thonk.
Do this before building this module:
Check that you have all components (see photo below).
Gather all the tools needed (see lists below).
The tools needed for this build are:
Soldering station or soldering iron.
High quality solder (lead free recommended).
Fine tipped side cutters.
Angled tweezers.
Philips head screwdriver.
Recommended accessories:
PCB holder (makes life much easier).
Knurled Nut Driver Tool (for tightening jack socket nuts).
Got everything? Let’s get on with it!
All components of the Sampler SMD kit.
BACK PCB
1. Headers and connectors
Connect the 10 and 6 pin female and male pin headers to each other and place them on the FRONT PCB with the male pin headers oriented upwards. Carefully place the BACK PCB on top and align the two PCBs as showed in the image above. Solder one pin on each pin header while taking care to keep the PCBs aligned. Check alignment again and then solder the rest of the pins.You should now have the pin headers solder nice and straigth onto the back of the BACK PCB.Solder the Eurorack power socket (J1). Keep in mind its orientation! See image for reference.Prepare the 14-pin male and female headers for the Itsybitsy RP2040 by cutting them to size if needed. Connect them together and place them on to the BACK PCB with the female headers facing the PCB and male headers facing up. Place the Itsybitsy RP2040 on top. See image for reference. Start soldering two diagonal corner pins on both the back side of the BACK PCB and the Itsybitsy RP2040 to align everything, and then solder the rest of the pins.
FRONT PCB
1. Headers
Connect the 10 and 6 pin female headers to the pin headers of the BACK PCB. Carefully place the FRONT PCB on top and align the two PCBs. Solder one pin on each pin header while taking care to keep the PCBs aligned. Check alignment again and then solder the rest of the pins. You should now have the pin recepticles solder nice and straigth onto the back of the FRONT PCB.
2. Fader LED replacement*
*NOTE: The faders that come with Thonk kits already have white LEDs and does not have to be changed. Skip this step if your fader LEDs are already clear colored!
The kit comes with red LED faders that can be changed to white LEDs to get the correct appearance. The LEDs are easy to pull out of the fader shaft. The white LEDs have long legs that need to be cut. Align the white LED with the red and cut the legs to the same length. When replacing the fader LEDs in the fader shafts, take care to orient the correctly as shown in the image above.
3. Jacks, switches and potentiometers and LED.
Now is a good time fit the caps on the two switches (S1, S2).Place the following components on the PCB without soldering them: – Jacks (J2-J9) – Non-latching switch with black shaft (S1) – Latching switch with white shaft (S2) – Illuminated switch (U$3) – Two 10kB faders (U$1, U$2) – 10kB tall trimmer potentiometer (VR1) – 10kA tall trimmer potentiometer (VR2). Make sure that the two switches S1 (non-latching, black shaft) and S2 (latching, white shaft) are placed correctly and have their protruding lines pointing up towards the faders, i.e. aligned with the silk screen!Carefully place and align the four white nylon spacers on top of the screw holes on the faders. Place the red/green LED (D10), minding its correct orientation. The flat edge and shorter leg must line up with the white line next to the LED. See image for reference. Carefully fit the front panel over the jacks, switches, faders and potentiometers, taking care not to disturb the nylon distances on the faders. Fit the four M2 screws in the holes above and below the faders and screw them in with a philips head screwdriver. Don’t over tighten them, just screw them in all the way without applying force. Finally, fit all the nuts for the jack sockets and hand tighten them, to hold the panel in place.Turn the whole assembly around and solder all the panel components while taking good care that the front panel aligns well with the PCB.. Remember to push the switches in while soldering them, or they will not fit correctly. Also make sure that the LED is correctly fitted in the front panel hole before soldering it.
4. Microphone
Fit the legs of the microphone (Q1) in the hole of the rubber grommet as shown in the image above.Place the microphone on the PCB in its correct orientation. Push the microphone slightly agains the rubber grommet while soldering it, taking care that it aligns well with the front panel. The grommet is used both as a spacer and to dampen mechanical resonances.Finally, tighten the nuts for the jack sockets and the screws for the faders so the front panel is sufficiently secured. The FRONT PCB assembly is now finished and should look like this.
5. Finishing up
Connect the FRONT PCB to the BACK PCB via their pin headers and recepticles. You are now done with assembly of the Sebsongs Sampler!
6. Powering up and testing
Before powering on, measure resistance with a multimeter between ground and + and – respectively on the power connector to make sure there are no short circuits. The resistance should be several kilo Ohms and the value should climb as the multimeter charges the capacitors.
