Kawai SX-240

Kawai SX-240 Image

The Kawai SX-240 is an eight voice, fully programmable polyphonic analog synthesizer released in 1984 as a follow up to the Kawai SX-210. It was manufactured by Kawai but originally released under the Teisco brand-name in Japan when Kawai bought out Teisco. The Kawai SX-240 and the Kawai SX-210 never got much attention due to entering the market during the time of the digital revolution and poor marketing. Its main analog competitors of the time were the Korg Polysix and the Roland Juno 6/60.

Being among the first in the era of MIDI, its MIDI implementation is very basic and it receives on all channels. In terms of patch editing, the SX-240 is very much like a Roland Alpha Juno or Moog Source which resort to using a dedicated data-wheel to edit the values of selected parameters. Four scroll buttons allow you to select the parameter you wish to edit. All the parameters have an LED light on the right hand side of the face of the SX-240 to make it very easy to see what you're editing, though only one parameter can be edited at a time. Saving your edited sounds is very easy thanks to a huge LCD display and using the keys of the keyboard to type the name of your edited sound alphanumerically.

Kawai SX-240 Image

The SX-240 has a big, wide and full analog sound, courtesy of its two analog DCOs and one sub-osc per voice. You have the options of poly-8, poly-4 and mono modes. In mono mode it is possible to have all 24 oscillators stacked into one for an extremely powerful sound. Leads, basses, brass, drones, pads and strings all have a unique analog sound on the SX-240. Strings and pads get especially warm and fluid when switching on the Ensemble effect, which is just a chorus. The SX-240 also has a function called Brass, which is actually a ring-mod effect.

Modulation possibilities are somewhat limited due to having just one saw wave on DCO1, but with adjustable PW and PWM plus a noise generator, you can find some great sound possibilities. The LFO can be routed everywhere in the DCO, VCF and the VCA. It also has an LFO trigger button to start or stop the LFO on command. The SX-240 uses eight SSM 2044 filter chips which help make up its powerful filter sound. The filter also strangely jumps into self oscillation around the value point of 98 to 99. There are also both portamento and glissando, though it was uncommon to find both of these effects on synths of the time.

Kawai SX-240 Image

The SX-240 also has the option of being placed in Split or Dual modes. In Split mode you can assign two patches to be played in a split on the keyboard. In Dual mode two patches can be played at the same time for a rich, warm, and layered sound. It also has a built-in, real time 1,500 note sequencer and chord memory.

The SX-240 is often said to sit somewhere in between the Polysix and the Juno 6/60 in terms of sound. While that could be a generally true statement, the fact is the SX-240 does not sound like either of them, but rather has its own unique analog sound. It's also pretty rare today. Most found second hand have NI-Cad battery issues causing a common symptom of not being able to retain saved patches to memory. This battery must be replaced or modified to a Li-Ion battery to ensure a long life for the SX-240. Even without showing any symptoms, it's best to have the Ni-Cad looked at for possible leakage.

Lookup Kawai SX-240 Prices

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43 Visitor comments
May 30, 2011 @ 2:15 am
Layering two sounds together on this synth can make for some of the coolest analog pads you will ever hear. There is not much i can say negative about this synth. Its built quite well and looks amazingly cool. I think this machine is very good for doing acid house music. ambient music and new wavish stuff. I will never sell mine . i have bought and sold many junos but this one always remains in the studio. becoming increasingly rare and desirable.
April 19, 2011 @ 5:33 pm
I have to say it's an extremely rich sounding synth with a very nice full sounding filter. The presets only hint at what the synth is capable of. The entry dial is not too much of a problem while programming. The sub-osc's are a nice addition to the sonic possibilities synth and adds a 3rd dimension to warm string pads or funky bass sounds. I also like the on board chorus which is warm and wide. In my growing analog collection, only the Chroma Polaris is more under-rated. A solid 4.5 for sounds, 4 stars just because it's focused and a bit limited (in a good way) like a vintage Oberheim.
September 21, 2010 @ 9:04 am
Good job using the cord mem in your link Freejazzer.You can also use the presets in reverse.If you edit every single preset patch you can do a tape out to a computer in and record the WAV on something like sound forge and make your own custome preset files.I have about 4 different preset files for my sx240.Tape out and the load in work great with computers
September 16, 2010 @ 4:39 pm
thanks for the preset file! The presets are not so bad, you can use the data knob for tweaking live like modulation.
The Sound ist really warm, and the chord melody is a really great composing tool.
I made a mp3 with the preset sounds:
September 9, 2010 @ 4:40 pm
that .wav file you have posted on the synth mania site for the sx 240, can that same file be used on the sx-210. I just tried it on mine and it never says stop when loading, it just turns off.

if anyone has a .wav file for the sx-210 whats the link. being that the data cassettes are 17 dollars now.
VSE Rating


User Rating

Rated 4.53 (954 Votes)

  • Check Price
  • The link above will take you to an eBay search for this synth to see active listings. If you don't find it there, try looking in our forum marketplace or post a wanted classified.
  • Specifications
  • Polyphony - 8 voices
  • Multitimbral - Dual or Split
  • Oscillators - 2 DCOs and 1 Sub-oscillator
  • Waveforms - Saw, Sine and Pulse with PW and PWM
  • LFO - 1 LFO with 3 waveforms: saw, square and tri. Speed, Delay, Reverse and Depth controls. Can modulate the DCOs, VCA, or VCF.
  • Filter - 24 dB/oct four-pole Lowpass with resonance, cutoff, envelope amount and dedicated ADSR envelope generator
  • Envelope - 1 VCA with HPF and ADSR envelope
  • Effects - Chorus, Hold, Portamento and Glissando
  • Sequencer - 1,500 note max
  • Arpeggiator - None
  • Keyboard - 61 keys
  • Memory - 48 Tone memories. Sequencer has 8 memories.
  • Control - MIDI In/Out/Thru
  • Date Produced - 1984
  • Resources & Credits
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    Review by Computron

    Review updated May 2010

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