X1L3 - Circuit bent - Synth mod - Casio PT82 / PT87

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Published on Jun 30, 2014 manufacturedZ3R0 .

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"Back to where it all started.

No eye candy or wooden ends etc. I wanted substance over superficiality. As much as i enjoyed doing the larger machines and will probably do more when i think i've something signifigant to add again (like midi / adsr etc) i started to feel that the curious aspect of these little instruments that sparked my interest was getting lost in some kind of pseudo synthesizer territory to the point where i might as well have just moved on to total synth diy and ditched working on these things. I've taken what i've learned along the way and what i can do now, miniaturised it all for purpose and put it to work with the fundamentals of the circuit bending that bought me to where i am and what i can do now. The charm and fun of a bespoke circuit bent keyboard but with a sound that stretches from vanilla to hell.

I wanted a compact machine which made space very limited. So i opted to ditch all the drum mute/distortion bends and keep just the pitch control bend which is so easily applied to these. Grunge bossa nova and disco get old fast. I wanted this to be something you could sample the hell out of for trashed up noise and quirky analogue hits and sounds. It's heart revolves around additional circuitry. An embedded psu/supressor to power the keyboard, filter and delay efficiently and of course the filter and delay themselves. It also has a CV input around the side that allows you to modulate the filter cutoff via other equipment. In this case a sequential circuits Pro 1 with note sequences programmed to send out cv patterns.

The intro to this video was made using samples from this machine and the sampler/fx processing of propellerheads reason. Probably most apparent as the intro peaks with the delay crash.

I think i've got it right and i think this is something different and diverse within the realm. But i suppose like most things it's a matter of taste as to if you like this particular flavour or not :)"

Modifications and embedded circuitry:

Analogue resonant filter with high pass and low pass bands
Gain, resonance, low pass/high pass toggle and cutoff
A brilliant filter based on the synthacon.
Lot's of resonance and a unique character.

Digital 'death industrial' delay
Rate, noise, feedback, off/on toggle
This delay variant is based on what i've learned from modifying delay pedals in the past.
Quite an aggressive version that can dial up some serious noise as well as act as a pseudo reverb/conventional echo.

PSU - DC hum suppression circuitry
A regulated psu is now built into the machine.
This gives a stable and quiet power supply to both the keyboard and additional circuitry as well as
providing a quiet output and excellent noise floor.
Input voltage is 9 - 12V
Since filming the video the master power switch has been moved from the side of the machine to the top control panel which is a better position and looks neater.

Control voltage input to filter cutoff
3.5mm jack. Allows you to hook the casio up to your cv enabled equipment to modulate the filter.
Examples of this are shown in the demo video.
The cv modulation is provided by a sequential circuits pro1.

Master pitch control
Gives a large global pitch range - demonstrated in the demo video
Since filming the video a body contact has been added to the side of the machine which gives a handy way of pitch bending and modulation.