SFC-101 Assembly guide

About the build

The SFC-101 was designed to be easy and fun for everybody to assemble. The project is based on through-hole technology and parts found in other popular DIY projects (Mutable Instruments, xoxbox, , etc.).

Although it’s an easy kit, if you’re not experienced with soldering and electronics it’s recommended to get some practice before you start. For instance this kit from Sparkfun will give you some valuable soldering-pratice and help you get your skills together before you start bigger projects. There is also this version with all the tools you need to start soldering at a killer price. Don’t be afraid because soldering is NOT difficult.

This guide should be as detailed as possible but if you think something is missing or unclear, get in touch: nicolas@sound-force.nl and this guide will get updated.

Soldering tutorials

Great learning resources about soldering :
Adafruit tutorial
Sparkfun tutorials
– EEV blog tutorials part 1 and part 2.


What you’ll find in your kit :

Start by opening all the bags of parts and organize them on your desk. Be careful not to loose any of the small pieces.

– 1 x SFC-101 Printed circuit board
– 1 x Teensy board micro-controller
– 2 x rows 14 male pins for the Teensy MC
– 2 x rows 14 female sockets for the Teensy MC
– 7 x IC sockets
– 4 x 4051 multiplexers IC’s
– 4 x HC595 shift registers IC’s
– 21 x 30mm faders + knobs
– 16 x tact switches + knobs
– 32 x LEDs + holders/spacers
– 5 x Rotary pots
– 1 x USB A connector
– 1 x USB B connector
– 25 x 12mm spacers
– 25 x 18mm spacers
– Enclosure (1x top panel, 1 x bottom panel (with 4 bumper feets marks), 4 x side panels)
– 4 x bumper feet
– 26 x M3 metal pan screws
– 8 x M3 nylon screws

The enclosure panels in your kit are covered with a blue protective plastic film. Remove it before trying to assemble the enclosure.

Things you will need :

– The best soldering iron you get can your hands on
Soldering wire (around 0.5mm for small pins, for big pins 1mm can be easier but is optional – lead-free solder with a “no-clean” flux core is our recommendation)
Flush cutters
De-soldering pump (optional)
Desoldering wick (optional)
– A good amount of time and patience. Don’t rush it and triple-check everything that you’re doing. Trying to fix mistakes after the fact is much more work than doing it correctly right away

Disclaimer : We are not responsible for anything wrong (including damaging the PCB or parts, electric shocks, malfunctions, fires, accidents involving a soldering iron) that might happen during the assembly of the kit. Everything you do while assembling the kit is at your own risks. Respect basic safety rules when soldering.


Always follow this order of operation during assembly. Soldering parts in another order makes proper assembly much more difficult. The key is to start with the lowest profile parts and to end with the highest profile parts. Another important thing is to always make sure that the parts are as close and as straight as possible to PCB surface before soldering. TRIPLE-CHECK everything that you’re doing. Some parts are easy to get soldered correctly (like the tact switches), but the IC’s and LEDs are polarized and if you solder them the wrong way around it won’t work. It sometimes can take a while to fix wrong solder joints, so think before you melt the solder!!

The bare PCB :


We’ll start with the front side of the PCB. Which means that we will insert parts in the front of the PCB (the side you can see the SoundForce logo on) and we’ll flip the PCB to solder the parts in place.

IC sockets : FRONT SIDE
Start by inserting the IC sockets in positions. Respect the orientation looking on the silkscreen on the PCB. Holding the IC in place, flip the PCB over and slightly bend 4 pins of the sockets like on the picture below. This keeps the socket in place when the board is upsidedown so you can use your 2 hands to solder it. You can go ahead and solder the 16 pins of the socket. Then repeat those steps for the remaining sockets.IC-pin-bent2

We have 2 kind of ICs in the kit, 4051 and HC95. Look at the silkscreen on the chips to recognize them. The 4051 IC’s belongs to the MUX 1 to 4 and the HC595 SHIFT_OUT 1 to 4 locations. The ICs come out of the factory with the legs at an angle wider than what will fit in the socket (see left on the picture). To fix this, gently place the IC on its side on a flat surface and bend the 8 legs to straighten the pins (see right on the picture). Repeat this operation for the other 8 pins of the IC. Be gentle, those pins are fragile.When all ICs have straight pins, you can press-fit them in their sockets. The ICs are polarized so the orientation is key! It won’t work the other way around. If even after all you still made a mistake, this is how you can gently remove the IC.

Tact Switches : FRONT SIDE
Place the 16 tact switches in the PB 0 to 15 positions. They snap-in very easily as shown in the picture.You don’t need any support to flip the PCB as they stay in place even upside down. Before you start to solder them, make sure that they are flush against the PCB. Go ahead and solder the 4 pins of every switch. Tucking the iron under the cruve of the pin gives you a great contact surface.



You need to make sure that every fader is straight and flush against the PCB surface before you solder them. Start by placing the first fader in position like this (push until it’s all the way inside the holes) :fader-snap-in2
Then holding the fader in place, flip the board and bend 2 legs of the fader like this :fader-pins-bent2
You can now go ahead and solder ONLY ONE of the 4 side mounting legs (the bigger pins) like this :
When the solder joint is completely cooled down, hold the PCB and the fader with one hand (use your thumb on the fader on the bottom of the PCB). With your other hand reheat the pad with the iron. When you see the solder re-flow (getting fluid again) push firmly against the center of the fader to bring it as far as possible inside the holes (you might have to use a glove as the back of the fader can get hot), then remove the iron from the joint and wait until the solder soldifies again to remove your thumb:
Solder now the other mounting leg across on the other side :
The reheat this leg and push on the back of the fader again as you did with the other leg :
The fader is now locked straight in place and you can solder the remaining 2 mounting legs and 3 signal pins of the fader. Repeat those steps for the remaining faders.

Rotary pots : FRONT SIDE

Place the first rotary pot in its place. You have to press it firmly in, it should snap in nicely. Start to solder one of the side legs, check if it’s straight then solder the second leg and proceed to its 3 pins.

pots above
pots under

Leds and holders : FRONT SIDE

Place the 31 LEDs into their holders and make sure they’re flush against the holder surface.LED+spacerInsert the LED in place, the longer lead of each LED is going into the “+” pad and the shorter lead in the “-” pad.ledsBend the LED leads at the back of the PCB at about a 45deg angle. Pull a bit of the leads when bending them to get the LED flat on the surface of the PCB.led-soldering2Repeat this for the 28 remaining LEDs. Then flip the PCB and solder just 1 pin of every LED. Use just a small amount of solder as those pins are very small. Temporarily placing the front panel on top can help to see if everything will fit. Make sure that everything is straight and then solder the 30 other second pins. When you’re done, cut off the rest of the lead that is sticking out of the bottom of the PCB. Do it one lead at the time. This is the result you are looking for :LEDs-straigtFIY, those LEDs have integrated resistors; that’s why no resistors are included in the kit.

The next parts need to get soldered at the BACK of the PCB.

USB connectors : BACK SIDE

ON THE BACK SIDE of the PCB, insert the 2 USB connectors (USB-A & USB-B). A bit like the tact switch, they snap-in very nicely on the board. Use a good amount of soldering for the bigger mounting pins and just a bit of solder for the 4 signal pins.

You can notice on the pictures some flux residue around the small pins. Flux is a chemical agent that aids in the flowing of the solder. It is found in the core of the soldering wire. When the solder joint cools down, the flux residue solidifies and sticks on the surface. As long as you get solder with “no-clean” flux you don’t have to worry about it. If you don’t use “no-clean” flux, you should clean the flux residue with isopropyl alcohol.

usb sockets 101

Upload the firmware on the Teensy
Please follow the infos on the support page to upload the firmware on the Teensy board.

Teensy sockets: BACK SIDE
Put the 2 rows of sockets ON THE BACK SIDE of the PCB, use a bit of scotch tape to hold them in place (flush and straight against the PCB). Then flip the PCB and start soldering. Don’t use too much solder as it would flow down into the socket and make it impossible to insert the male pins later on. A good tip : Just solder 1 pin at first. Check if it is straight. If not heat the pad again and correct the position. When in place, finish the 7 other pins. Repeat this for the other row.

PCB Spacers:

Insert the 12mm male/female spacers on top and the 18mm female/female spacers on the bottom and screw them together.


Insert the Teensy in its sockets

Insert the 2 rows of 14pins in the socket, place the teensy on top and solder the pins with very little solder. In this fashion : https://youtu.be/ArQKxe7X_q4?t=2m42s
teensy top viewDon’t mind the extra pins sticking of the teensy on the picture above, it was used for testing but they are not necessary for this project.

USB Cable:

Insert the micro USB cable into the teensy and the USB A connector. You have in your kit a much nicer and shorter cable.
teensy +usb

Programming the Teensy:

Find the firmware and follow the guide on this page : http://sound-force.nl/?page_id=1151


It’s time to plug your SFC-101 into your computer to try the controller with the U-NO-LX plugin. You can find a mapped preset for your controller at http://sound-force.nl/presets. The MIDI monitor software is helpful to check if every switch and faders are outputting MIDI cc correctly.

Screen Shot 2014-10-08 at 9.18.27 PM

Enclosure assembly :

Please note the following pictures are showing the assembly of the SFC-60, but the SFC-101 assembles using exactly the same principle. New photos coming shortly.

Once you’re sure that the controller is working, you can assemble the enclosure. Screw the 7 remaining 12+18 spacers together.


Screw the PCB on the bottom panel using 19 screws. Then screw the 12+18 spacers to the bottom panel on the remaining 7 outside holes:
Insert the sides in the bottom panels starting by the right side (where the USB connector is). The notches on the panels are there to help you assemble it properly:

Insert the front panel into the side notches (you might need to give it a little pressure):
front-wood-assembAttach it with the 8 nylon M3 screws. Turn the controller over and apply the 4 bumper feet on the 4 small holes at each corner. They peel right off the support sheet. Then insert the 22 fader caps and the 15 tact switches caps.front-panel-finalYou’re done! Congratulations. Enjoy your SFC-101 MIDI controller. Check our the manual on our support page with the DAW set-up.


– If a group of 8 faders or 8 LEDs are not functional, the problem is most likely a wrong connection in one of the IC’s. Follow the traces on the PCB to see which IC the faulty parts are connected to. Maybe you soldered it the other way around; maybe you used too much solder and created a short-circuit; maybe a bad or cold solder-joint must be fixed.
– If one isolated LED is not working, you probably soldered it the wrong way around. You can apply a 5V power source (with the USB cable disconnected) on the pins of the LED to check if that’s the problem before you try to unsolder it.
– The switches are connected directly to the Teensy micro-controller. If one switch is not working, check its solder joints.
– If nothing happens when you plug the USB cable in the USB-B connector, try connecting the Teensy directly into the computer. If it is then working, there is most likely a connection problem with the 2 USB connectors. The signal pins of the connectors are very small; check if you didn’t short circuit them.