If you want to truly enjoy the benefits of a circuit bent instrument, the Casio Sk-1 is the most versatile of all machines in the genre. 
This one is ready to apply endless layers of textures, pads, and freshly morphed original sounds into your music.
Circuit-bent SK-1's create incredibly strange sounds and beats.

I've added a separate LFO circuit that animates the sounds and sampled sounds for modulation.
Also, an opto cell that allows for theremin type of pitch work and total chaos in other patches.
It has an LED with ON/OFF switch that pulses and adds a modulating envelope glitch.

In addition, it has 9 bend switches that add strange modulations, algorithmic brain wave oscillations, insect emulations, whacked out drum beats, chaotic bass, syncopated rhythms, flanging, echoing, looping, the effects go on and on for incredible combinations only limited by your imagination.

I've added a control knob on the front that allows you to dial out the drums. The ability to eliminate some sounds is invaluable to say the least.

It also comes with an ATARI joystick port (joystick NOT included) that renders INCREDIBLE effects in each direction the joystick is moved as well as the button for cool effects that mimic some vintage Atari video game sounds.

Also, there's a pitch control knob with switch that allows you to choose between the original clock or a precision oscillator . This pitch knob greatly effects pitch several octaves. I'm using the getlofi ltc1799.

I've also added a soft reset button and a balanced 1/4" output jack.

I've added pitch bending body contacts that add great tremolo effect by touching both

 IM ALSO INCLUDING A REMOVABLE RCA PATCHBAY MODULE THAT PLUGS INTO THE ATARI JACK WHEN THE JOYSTICK ISNT PLUGGED IN.

All keys and buttons are nicely in place, this keyboard is in great condition, it will certainly please you. I've also chosen to leave the onboard speaker intact so you can use it on the go or anywhere you'd rather not drag your amplifier, a huge convenience factor.

You'll enjoy creating tons of new compositions with this if you're into experimental,  dreamy, robot, computer rock soundscapes and ambient noise not to mention beautiful soundscapes as well, virtually whatever you're into.

It now features multi-voicing button that activates a very space invadersesque type of bass line.

This is a very smooth soundscape creator that fully retains all of the incredible SK-1 original features including: the sampler, synthesizer feature, synth drums, 13 envelopes, portamento and vibrato among a terrific array of features that make this an absolutely fascinating mini synthesizer. 
It Works as an original, normal sk-1 until you turn on a glitch.

I based this somewhat around the sounds i was hearing in tetsu inoue's incredible work, that was all i listened to while mapping the bends for this piece.
 

Circuit Bent Casio SK-1 Sampling Keyboard