Update 24th of January 2024: Made a couple more. I also have a frontpanel available with the labels for the Arp rather than the synth. It's slightly smaller with 12HP. You can select it as product option.

What is it?

The Kepler (named after a German scientist) is a digital module for 3U Eurorack systems. This module is my take at porting the Bastl Kastle Arp to Eurorack. The size of this module is about 14HP.

This advertisement is for a PCB and an Aluminum frontpanel as shown on the first image. The last photo's show what the end result looks like. The SMD components are already soldered onto the board but you have to source and assemble the through-hole components by yourselves in case you select the 'Kit' option:

• 15x Thonkiconn mono jacks
• 8x 100kOhm potentiometer
• 1x 3mm LED (color of choice)
• 2x 2x3 pinheader (for flashing the firmware)
• 1x 2x7 pinheader (for eurorack power supply)

The firmware has to be flashed using the Arduino IDE and an ISP programmer. Details can be found under Documentation.

Why did you make it?

A while back I came across the Kastle line-up and I quite fell in love with the ARP. Such a tiny box but due to some clever software very musical and full of surprises and happy accidents. That's when I decided to try and integrate it into my Eurorack system. What you see before you is the end result! I am quite happy with the end result and made a few more than I need myself, so I'm looking to sell these to cover some of the development costs. If there is enough interest, I have designed it such that I can do more production runs easily.

What makes it special?

Compared to other Eurokastle ports, this version has omitted the switches in favor of patch points. For the ARP firmware this means that you can change the chord using CV. Pretty significant if you ask me! Next to the ARP firmware is this module also compatible with the Synth and Drum firmwares!