Shared Projects by mangros

Use Thonkiconn jacks.

Fits in the space of IC113 and provides buffered trigger outs for LT MT HT RS. These will need connecting to jacks. The triggers are 5V and roughly 2ms.

The Jasper’s digital noise circuit is clocked by the keyboard scanner clock. This is fast enough to produce a natural sounding white noise.

This PCB will fit in the IC34 (the CD4006) socket and allow an alternate clock signal to be connected to the digital noise. A suitable source would be Oscillator 2’s square wave output after R99. This will create a raspy 80s computer explosion texture for the noise that will scale along the keyboard. (The Jasper LFO doesn’t go fast enough to achieve the main effect here.)

Fitting an SPDT switch will allow selection between the original noise clock and the alternate clock signal.

Noise clock install

Use double-sided turned pin headers to mount this board to the main Jasper PCB.

Side view

If keeping a socket on the Jasper PCB and using a socket for the 4006 on this PCB, space under the panel is very tight. The official BOM suggests 17mm spacers and depending on your IC sockets, the board may not fit underneath the panel.

I used 18mm spacers so everything fits tightly but remains removable.

Mod board for the Jasper synth adding two different XOR waveforms that sound like ring modulation.

XOR1 is Osc2 x LFO (most flexible with an LFO modded for higher rates)

XOR2 is Osc1 x Osc2

The outputs are placed on Osc2’s rotary switch (you’ll have to adjust the lock to allow two extra rotation positions)

(Following images are for a v1 Jasper. Pins may differ slightly in later revisions.)

XOR pin refs

(wire colours below don’t match the above diagram) Jasper XOR wired