Parts Prep

Get all of your parts together, as well as the headers.

The DAC is optional, so we'll add that last.

ItsyBitsy Headers

Solder in place the two inner rows of ItsyBitsy short female headers.

ADC Prep

The ADS7830 analog-to-digital (ADC) boards each have eight channels to read the faders and convert their analog values into 8-bit digital messages sent over the I2C bus.

The first ADC board will use the default I2C address and will be soldered closer to the ItsyBitsy. The second one will need to be set to a different I2C address. Heat the AD0 pads and jumper them with solder.

Solder the first board into place with header pins as shown, being careful to match the orientation of the silkscreen shown on the Faderwave PCB.

Clip the extra pin lengths with diagonal cutters.

Second ADC

Repeat for the second ADC board, being careful to match the silkscreen orientation, as this board is rotated 180º from the first board.

Reset Button

Insert the tactile button and then solder it in place.

OLED Prep

Solder in short header pins as shown. Then to modify the board to use SPI mode, flip the OLED over and cut the traces for J1 and J2.

OLED Mount

First, solder in place the short header for the OLED display.

Then, fasten four M2.5 x 8mm standoffs to the board as shown, screwing four short screws in from under the PCB.

Insert the OLED into the headers, and then screw in four screws from the top to secure.

Audio Out

Use two M2.5 x 6mm screws with nuts to create a stabilizing mount for the TRRS 3.5mm breakout.

Then, solder it in place with a header pin row as shown.

Rotary Encoder

Solder the rotary encoder in place.

ItsyBitsy

Solder the short header pins to the Itsy Bitsy as shown, then insert it into the board with the USB jack facing left.

In Go the Faders

Check for any bent pins and straighten them. Then, insert the slide potentiometers into the PCB (they can only go in one way).

You can use tape or a rubber band to hold them flush to the board as you flip it over and start soldering!

Note, the four hardware tabs can require increased soldering iron heat to get the large copper ground planes hot enough so solder easily.

Option A: Solder the RC Filter

If you want to filter the audio a bit from the high end, solder in the 1k resistors and 0.1uF capacitors as shown. There is one RC pair per channel of the stereo output that will massage the audio on its way to the left and right channels of the 3.5mm TRS output.

Option B: RC Circuit Bypass

To bypass the resistor/capacitor filter on the audio outputs (they can be used with either ItsyBitsy RP2040 or M4, but are more helpful with the PWM out of the RP2040), cut the trace between the left and middle pad of JP1 and JP2. Then, solder a jumper blob between the middle and right pad of both.

Optional DAC Output

The Faderwave is a platform for audio experimentation, so I decided to include a 16-bit DAC output for possible control voltage (CV) use on vintage and modular synthesizers, such as Eurorack modules. This is optional, but if you think you may want to try it out at some point, go ahead and solder it in place now!

Fasten the panels with four M3 x 12mm standoffs, four M3 hex nuts, and eight short M3 screws.