Casio SK-1 Sampling Keyboard Circuitbent

Crazy inspiration. Will ship freshly circuitbent. In very good condition, serviced and with warranty.

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PRICE: £590.00 EX VAT (£708.00 INC VAT)



Crazy inspiration. In very good condition, serviced and with warranty.

Modified and ready to ship now!


So much crazy inspiration in this compact little synth whether you’re sampling or just messing with the onboard rhythms and sounds. The immensity of the sounds this diminutive frankensynth creates is simply astonishing. Punches way above its weight. A source of constant joy!

There’s a very stripped back test video below, plus you should watch this more involved demo from Tony on instagram.

Requires a 7.5v centre negative power adaptor for use, or 5 AA type batteries (not included).



Below are the notes from Circuitbenders which give some indication of what’s possible.

WARNING: As with any circuitbent machine this unit may appear to lock up or crash on occasions. Don’t panic, these machines are operating way outside of their designed tolerances so sometimes crashes can be a common occurrence. If the machine won’t respond first try pressing and holding the soft reset (red) button on the side for a few seconds. Many times this will get the machine working again without having to turn it off and loosing and samples in memory. If the reset fails turn the machine on and off using the power switch or just unplug your power adapter. Usually if the machine gets locked playing one note you can stop it by pressing down more than four keys thus forcing it to run out of polyphony.


The controls are split into three main areas although the effect of some switches depends entirely on which sound or sample you are currently using. Some switches or patchbay connections may appear to do nothing when using certain sounds or cause total chaos with other sounds. The sound control groups are:

Polyphony Drop Switches:

The SK-1 has a maximum of four notes of polyphony (it can play four notes at a time). These controls are the five switches on the front left of the machine. Each switch can individually turn on/off one voice of polyphony while the remaining switch will turn the percussion sounds on and off. When the machine starts producing random crunching sounds and loops (as it will with a little experimentation) you will often find that each voice is producing a different sound. Use these switches to isolate individual effects or turn off unwanted sounds. These switches may cause an audio click when used, unfortunately there is no way to avoid this happening.

Alteration switches:

These are the six switches to the right of the keyboard. The effects of these switches varies depending on the sound or sample selected. They are especially effective when mutating the rhythm/chord accompaniment feature.


The patchbay consists of 20 x 3.5mm jack sockets plus two patchable switches. The patchbay is split into 16 sockets mounted in the speaker grill, and another 4 in the area above the Casio logo. You can make as many connections as you want between any jack sockets with standard jack cables. Each connection will produce a different effect but using too many connections at any one time may cause the machine to crash.
The two patchable switches are the four sockets and two associated switches above the Casio logo. Each switch is connected to two sockets and is used to connect and disconnect a link between these sockets. This allows you to use two cables to patch a switch ‘in line’ with any patchbay connection, so you can turn the link on and off with a flick of a switch instead of having to repatch cables
As some connections will disable the keyboard to some extent, it is often useful to make a connection after you play a note, or set a sample looping with the loop function, and then hold a note while trying different patchbay connections, rather than playing notes with patchbay links already connected.
We would not advise inputting any external signal into patchbay sockets from any other source.

Trigger Input:

This is the 3.5mm jack socket on the right hand side. A standard +5v analogue trigger pulse signal will clock the one key play function in the same way as pressing either of the one key play buttons. Each trigger will advance the sequence one step and the further clock must be applied at the end to reset to the start of the sequence. This means a four note sequence needs five triggers, the fifth being the reset trigger.

Pitch Knob & Switch:

The switch on the rear of the keyboard selects between the standard pitch setting, or a variable overall pitch set by the knob on the left hand side. As this knob is actually controlling the clock speed of the whole system, it will also change the tempo of the rhythm’s and demos etc.

Soft Reset:

This is the button on the side of the unit. If the machine seems to have locked up just press and hold this button for a few seconds and it will usually unlock again. If the machine starts looping a sound and will not stop you can usually stop it by pressing more than four keys at once so the SK runs out of polyphony. If all else fails either turn off the machine or unplug the adapter. If you have batteries installed you won’t lose any samples in memory when you turn it back on again.

Percussion Output:

This is the new 3.5mm jack socket on the back. Plugging a jack in will remove the percussion from the main output and redirect it out of the percussion output. The signal level will be fairly low compared to the main out.

The main advice we can give is to experiment. There may be a lot of features available on this machine that we have yet to discover.


In excellent condition with minimal wear. Freshly circuitbent/serviced. 3 months warranty. Please see photos or get in touch if you require more information on condition.

Voltage Information

See description for more information.


For sales in UK the price will include 20% VAT. Buyers elsewhere may incur VAT or other local taxes on import.

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