Sweet Sixteen - build guide & manual

To build the Sweet Sixteen you need:

  • The partial kit (PCBA with all SMD components populated and 16 faders)
  • 32 mono and 2 stereo thonkiconn jacks
  • All components listed in the BOM or the Mouser cart (Teensy 3.2, slide switches, bi-color leds, headers...)

IMPORTANT: Leds must be soldered reversed (anode to GRND and cathode to V+) in order to get green light for positive voltages and red for negative ones!

Solder 2 rows of pin headers to the Teensy and also the SMD header to the + - pads, those 2 pins must be aligned with the second pin of the lateral rows.

Cut the pins of the female headers for the Teensy (ideally to 1,6mm)

Solder all the pin headers except the eurorack power one (that way you'll have more room to solder the faders and leds) and put some insulating tape to avoid shorts with the faders.

Next solder the faders, take care to not apply too much heat (max 340ยบ during 3 seconds). Once the headers are done place the rest of the components and the panel, make every led is in it's hole before soldering,

The aux pcb allows to switch on/off the i2C pull-up by swapping 2 jumpers. The jumpers in this image are making the pull-up ON.

In this position the pull-up is OFF.

Don't tight the metal screws at all or the faders won't go down at all. If you got the nylon ones is ok, they're smaller

Download the source code here or the compiled .hex file here.

You can flash the Teensy using the panel USB (with the module powered) or the Teensy's micro USB (with the module turned off).

To modify the midi CC and channel assigned to every fader you need the source code, install Arduino IDE and Teensyduino, but no coding skills are necessary. Just change those values in the 'config.h' tab and press 'upload' (the top left arrow).

Different midi channels and midi CCs can be assigned for USB and trs midi outs, but due to the difference in bit resolution and how the code is done, when PitchBend is used, it should be selected for both minijack and USB outs. There is also a mod I made to allow midi note generation (and so CV to midi note) but the module is so sensitive that generates a shit load of notes, so you can try it as an experimental feature, but not as a clean & useful CV2Midi thing, unless some more time is spent tweaking the code, as example this image, the Midi note transcription of an stepped voltage coming from the MT Touring Machine.

To make the Sweet Sixteen work with the ER-301 you need to activate the 'i2C pull-up' and uncomment those flags in the 'config.h' tab of the firmware:

  • #define MASTER 1
  • #define bootDelay 10000

There's a compiled .hex that has those settings ready to go.

Set the +5V source to power the Teensy with this jumper:

  • REG - onboard LDO regulator
  • PSU - the 5v rail of your rack

Use JP1 jumpers to swap the midi trs pinout as follows:

  • K - Korg / Makenoise
  • A - Arturia / Novation

JP3 is an i2C port, just in case you want to have it as a permanent connection.

Do not hot plug the i2C trs jack, and never plug there a CV source unless you'd like to destroy the Teensy board.