k2 is a version of the kastle2, the latest desktop-device from Bastl Instruments especially tailored to the AE Modular format.

k2 is the realization of the open-source kastle2 platform from Bastl Instruments, slightly reconfigured for integration into the AE Modular ecosystem.

It is a complex module which drastically changes its behaviour depending on the code which is running on its processor (at the time of writing, there are three kastle2 variants: FX Wizard, Wave Bard, and Alchemist, all of which are directly supported by k2).

Of course, being wonkystuff®, we've renamed the three variants to add a bit of local colour (Old English!):

• seolfor-smiþ (Alchemist)
• gleó-man (Wave Bard)
• lyb-lǽca (FX Wizard)

As with the original Kastle modules, functionality splits into two main areas; LFO and sound generation.

LFO

The LFO is actually split into two parts, the well-known 'rungler' based CV generation, now extended with the ability to generate user-definable patterns of gate pulses, and the traditional square/triangle LFO.

These two parts are controlled independently: Gates and rungler are driven from a tempo control (also externally syncable), whilst the Tri/Square can be free-running or synced to the tempo.

Sound Generation

The sound generation is where things get interesting!

seolfor-smiþ

seolfor-smiþ is a flexible synth voice with 5 different synthesis algorithms (Filter, FM, Supersaw, Hypersine, and Glitchnoise). Although this firmware is not (yet?) open-source, k2 can be programmed using Bastl's online tool.

In comparison to the original Kastle series, this feels like a solid hybrid of the ARP and original Kastle.

editor: https://apps.bastl-instruments.com/alchemist-laboratory/
Full operational details: https://bastl-instruments.com/instruments/kastle-2-alchemist

gleó-man

gleó-man is a configurable sample-playback & manipulation machine. Using Bastl's online tool users can select different soundpacks, or can construct their own up to 89 seconds (mono) split across several banks of samples.

In comparison to the original Kastle series, this feels like a huge upgrade of the Drum variant!

editor: https://apps.bastl-instruments.com/wave-bard-sample-loader/
Full operational details: https://bastl-instruments.com/instruments/kastle-2-wave-bard

lyb-lǽca

lyb-lǽca has no comparison with the original series as it is a patchable effects unit! The firmware contains 9 FX modes, variants of delay, amplitude and pitch-shifting effects, which can be modulated in subtle or extreme ways, depending on your inclination…

editor: https://apps.bastl-instruments.com/fx-wizard-chamber/
Full operational details: https://bastl-instruments.com/instruments/kastle2-fx-wizard

Differences

The k2 has some small changes when compared to the original Kastle2:

• External sync input has a dedicated switch:
  • On the original, external sync was enabled when a 3.5mm jack was inserted to the sync-input jack. In AE Modular, we don't have switched jack inputs, so a latching push-button has been used (top-left). External sync pulses are still accepted when this button is not pressed, however the external sync interacts with the internal sync — a lot of the time with interesting results!
• Audio input has a dedicated switch:
  • As with Sync input, external audio input on the original is enabled when a 3.5mm jack is inserted. For the lyb-lǽca firmware, this switch has no effect (audio input is always enabled), however with seolfor-smiþ and gleó-man, the external audio input can be muted.
• MIDI/IMDI input:
  • In place of the Sync R signal of the original, we have added an IMDI input so that k2 MIDI capability can be used alongside other IMDI modules in the wonkystuff® and Tangible Waves range. This is in addition to the MIDI support over USB-C, and allows MIDI synchronisation to be used through TRS.
• RESET button:
  • Firmware is updated by placing the Kastle2/k2 into bootloader mode. In the original Kastle2, this is done by holding the SHIFT button down whilst powering on the device. In k2, the same behaviour is acheived by holding the SHIFT button down whilst pressing RESET. On its own, RESET can also be used as a performance tool, simply stopping the module in its tracks (releasing the button will restart the module).

https://wonkystuff.co.uk/k2.html