Kawai S-100F / Teisco S-100F – “Terra Incognita”?

Hardly believable: A few of those “little giants” (monophonic synthesizers from the late 70s) seem to have disappeared completely from our memory. Take, for instance, the Kawai/Teisco Synthesizer-100F. Like reminiscences of experimental bygone days, some examples of the S-100F can still be found on the used market. Amazingly low priced, by the way, considering the fantastic (powerful!) sound of this flexible analog synthesizer.

Kawai S-100F / Teisco S-100F Synthesizer

Indeed: Our Synthesizer S-100F (our quasi “Terra Incognita”) isn’t of impressive size. It’s not completely unknown, but the exploration of the S-100F has by no means been extensive. Details available on the instrument are few and far between. Research on WorldWideWeb quickly pulls you back in time to long-forgotten web sites.

Things aren’t much better on the technical literature front. Peter Forrest (“The A-Z Of Analogue Synthesisers”) includes a small entry on the Teisco S-100F, at least. But Julian Colbeck (“Keyfax”) takes no note of the instrument at all. Generally speaking, not only do few articles exist, but there are relatively few quality pictures of the Kawai/Teisco S-100F available. Not even the Kawai/Teisco catalogs (!) make mention of the instrument, as far as we know. To be sure, Teisco S-60F and S-110F can be found. Teisco S-100P (preset-synthesizer) just as well. But nothing whatsoever about Teisco S-100F.

Still, to be honest, the S-100F is not a “completely rare” rarity. The instrument turns up again (and again and again) on the used market. Whereby, Kawai S-100F is more certain to be seen than the identically built Teisco S-100F.

Kawai S-100F / Teisco S-100F Synthesizer

Synthesizer-100F … when did it all start?

The prize goes to the reader who knows the answer to that. When did the S-100F come onto the market? Peter Forrest assumes the “early 80s”. Possibly. But in the catalogs of those days there is no S-100F to be found. Vintage Synths proposes 1977, Polynominal 1976. Both possible. The hardware – partly in the style of early Roland synthesizers – would seem to substantiate that. But neither the rare Teisco Synthesizer-100F “Owner’s Manual” nor the S-100F circuit diagram (available on the internet) divulges that first year of manufature.

Let’s agree on “late 70s” and sing a quick “Happy Birthday” to the 40+th anniversary of the S-100F!

The S-100F in detail

Simplicity and ingenuity are often closely related. As with the S-100F. The simplicity of the instrument goes hand in hand with its supreme musical productivity.

Kawai S-100F / Teisco S-100F Synthesizer

Der S-100F contains:

  • 1 VCO (waveforms: saw, rectangle, noise)
  • 1 LP VCF (VC 24db LowPass with resonance)
  • 1 HP VCF (manually adjustable only)
  • 1 VCA (with Gain function = HOLD)
  • 2 AD/AR (for VCF/VCA/VCO)
  • 1 LFO (0.03 – 50 Hz)
  • Portamento

The features are not really that impressive. The 3-octave keyboard just makes it into the category of “big enough”, but performance options such as pitch-bender or modulation-wheel can nowhere be found. Still – the Kawai / Teisco S-100F tops many Roland Synthesizers and many Moog- and ARP-Synthesizers when it comes to sound flexibility and musical expression. Without even trying.

Kawai S-100F / Teisco S-100F Synthesizer

TWO Envelopes – snappiness is the thing

The S-100F envelopes feature “presets” that are strongly reminiscent of various Korg synthesizers (800DV, PS-Series). Despite the fact that only Attack and Decay/Release can be adjusted, the few sliders available suffice in combination with the “presets” for nearly all musical performance situations. Both KYBD trigger and auto-trigger via LFO are available. One of the fine qualities of the envelopes is their extraordinary snappiness. Ideal for percussiveness and sequencing.

Then there is Portamento, which again is partly related to the envelopes. Mode A activates a general glide effect (Portamento!), whereas in Mode B the effect only pertains to notes played legato. In the latter mode, the envelopes are triggered just at the outset and the volume level of the sound is gradually reducing. Thus, the longer you play legato, the less sound you have. Mode C is similar, but the envelopes retrigger (despite legato playing) with every single note, so that the sound volume is not reduced.

Portamento in legato mode (Mode B / Mode C) is a funky and tremendously useful substitute for the (missing) pitchbender, by the way. That’s merely a small aspect, but further evidence of the well thought-out S-100F concept.

Kawai S-100F / Teisco S-100F Synthesizer

ONE OsCillator – frequency range is the thing

There’s only one VCO, but this one is a cracker. Switchable through 7 steps, it ranges from 2′ to 64′, and comes with a separate LOW mode. It has two waveforms: SAW and RECTANGLE. There is no PWM, though, which is a pity. The VCO can be modulated by ENV I / ENV II, LFO or DELAY VIB. That latter is again the aforementioned LFO, but with a fixed triangle wave and – nomen est omen – delay.

The uniqueness of the VCO is characterized by four aspects. First, its voluminous sound (a beefy oscillator is musically sufficient in a large number of cases). Second, its LOW mode, which turns the audio oscillator into a voltage controlled (!) Low Frequency Oscillator. Third, its usefulness as a modulation source for the filter (VCO-to-VCF FM). And fourth, its TUNE slide, enabling the user to continuously surf through the entire audio range.

Let us explain. As soon as the octave range (2′ to 64′) is selected, TUNE acts as a Fine-Tune slider, with a range of approximately +/- 7 semitones. Thus, it can be used for – well – fine tuning, but can also serve as a kind of pitch bender (which – admittedly – needs some practise to get used to). In LOW mode, however, the TUNE range changes dramatically. It allows you to sweep through the entire (!) frequency spectrum, from 0.03 Hz up to high audio frequencies (… a feature you might recognize from the Moog Multimoog, by the way). One snag: Fader range is a bit short – you only have a few centimeters at your disposal to control a few thousand Hertz, so it’s a bit fiddly to operate. But it’s still a great option – useful, expressive and rarely to be seen on a non-modular mono-synth.

Kawai S-100F / Teisco S-100F Synthesizer

ONE Filter – dynamic behaviour is the thing

The S-100F filter is a strong 24dB LowPass VCF with resonance (called “Peak”). A wide range of dynamics is at your fingertips, since the VCF works efficiently throughout its entire range from 16Hz to 20kHz. And a wide range of timbres is at your fingertips, too, since the filter resonance has such beautiful characteristics. At maximum PEAK values ​​(and minimum CUT OFF values), the VCF self-oscillates, which enables (in combination with the ultra-fast envelopes) all kinds of exciting electro-percussion sounds.

VCF modulation takes place either via ENV I, the LFO (which – let us remind you – goes up to 50 Hz), the VCO (sawtooth or rectangle wave, with different sonic results) or via an external EXP pedal. Unfortunately, the external modulation source can only be switched on as an option, which means that VCO modulation and external modulation are not simultaneously possible *. However, the Kenton CV / Gate Kit listed below offers an additional FILTER CV socket, which, thankfully, solves the problem. More later.

[* If EXP PEDAL CV is not activated in the VCF department, the pedal voltage automatically goes straight to the VCA (> external volume control). Another aspect of the cleverly designed S-100F.]

Kawai S-100F / Teisco S-100F Synthesizer


Its lack of connectivity may have been one of the issues that contributed to the inexplicably low popularity of the S-100F (and maybe still does today). The fact is: The connections of the Synthesizer-100F are – to say the least – unusually arranged.


  • Audio IN (ext. audio signal “optional” to the oscillator – not both in parallel)
  • Audio OUT (High / Low – two audio channels can be used simultaneously)


  • IN (combined CV / gate signal input “from” another S-100F)
  • UPPER OUT (combined CV / gate signal output “to” another S-100F)
  • LOWER OUT (combined CV / gate signal output “to” another S-100F

Pertaining to the control voltage connections: IN and OUT can be used to control an additional  (or a third, a fourth …) S-100F in parallel. Either for layered sounds (monophonic) via the UPPER OUT socket, or for two-part playing (duophonic) via the LOWER OUT jack. Master S-100F OUT > Slave S-100F IN – a single cable is sufficient (it works perfectly), both instruments operate in parallel.

Kawai S-100F / Teisco S-100F Synthesizer

A global external CV control is also possible via the IN jack – at least to some degree. For example: Octave jumps and limited sequences work well when connected to a Doepfer A-155 sequencer. The the S-100F receives both the CV value ​​and a sort of GATE, but the CV values ​​are inverted (we don’t know why) and GATE operates rather in the sense of HOLD – the tone is maintained, but the envelopes are not retriggered during the sequence.

In sum, the SYNTHESIZER CONTROL VOLTAGE interface can be seen as an emergency solution for simple (external) pitch control of the S-100F. However, it is no substitute for a proper CV/Gate interface. And this is where the previously mentioned Kenton interface comes into play …

Kenton CV / GATE / FILTER CV interface

Not quite cheap at 84 GBP plus shipping (and installation), the Kenton interface does allow the Kawai / Teisco S-100F to be correctly integrated into a modern studio setup / into a modern modular environment with regular 1 Volt/Octave standard.

The Kenton kit comes with 3 small sockets – 3.5 mm – with cables, a switch (which must be in the correct position for external control), a small circuit board and the necessary circuit diagram for installation.

Kawai S-100F / Teisco S-100F Synthesizer

Kawai S-100F / Teisco S-100F Synthesizer

If you find the mini jack sockets (common with Kenton) unsuitable, you can replace them with large sockets. As everywhere in life, there are arguments for both sides. Kenton’s MIDI-CV interfaces (Pro-2000, etc.) have those mini jack outputs, taking into account the issue of MIDI integration and the uniform use of small patch cables for the interfaces as well. In addition, 3.5 mm corresponds to the Eurorack standard. In this respect, it is the ideal size for many modern studios / for modular systems.

On the other hand, if you want to optically adapt the interface to the S-100F, you may prefer large jack sockets. This leads to a clever idea, by the way: The SYNTHESIZER CONTROL VOLTAGE Interface sockets of the S-100F, which are of limited use anyway, can be disconnected internally and used instead as inputs for the Kenton Kit.

Thus, the S-100F remains unchanged (!) on the outside – and still has those Kenton 1V/Octave CV/Gate inputs (including the separate filter CV socket). There’s a picture of this solution further below …

Kawai S-100F / Teisco S-100F Synthesizer

S-100F – a sound similar to the ARP 2600?

We nod ruefully … yes, yes, yes, yes – those comparisons are being overused around the world: ARP 2600 here and Minimoog there. Only these two instruments seem to play an important role in synth history. The Korg MS-20 is affectionately known as the “poor man’s ARP 2600”. This may be correct conceptually, but not in the sense of musical potential and power. The reverse is true of the Kawai/Teisco S-100F: Conceptually far away from the ARP 2600, the instrument is musically surprisingly close indeed.

Meaning …? Dry, ultra-deep basses are at their best with the S-100F, especially in combination with the sharp “Zapp!” of the ultra-fast envelopes. Effect sounds come in countless, unheard-of variations. Just dare to think a little outside of normal parameters: Oscillator-to-filter-modulation, alright.

Don’t forget high filter resonance settings for those extra-experimental timbres – timbres not unlike those coming from a ring modulator. Now, modulate the VCO via ENV I or ENV II, while – at the same time – changing the VCF frequency drastically via external control voltage (Kenton’s interface waves as we go by). Crazy and cheeky: This is the S-100F.

Kawai S-100F / Teisco S-100F Synthesizer

Quickly switch the VCO to LOW mode and slide from sub-audio to 4000 Hertz (or more) with that grandiose TUNE fader, revelling in the impressiveness of the audio frequency (and modulation!) range. Here, the S-100F sounds … incredible!

A few simple tweaks – four or five adjustments – bring you back into “normal” realms. Select a different ENV preset, increase the VCF envelope attack and achieve a powerful solo sound (with a hint of vibrato LFO) in a matter of seconds. Then adjust the ENV again – attack and decay / release to “very short”, change VCO from sawtooth to rectangle, set 64′ and return to the outcome of this small exercise with an ultra-deep bass. Voilà!

Of course, the S-100F has its conceptual limitations. Just one oscillator, just one LFO, slimmed-down envelopes, no PWM. And its size! Almost a midget! 55cm wide, weighing just 6.7kg, and with a power consumption of only 6W, the synthesizer falls into the “little whipper-snapper” category. Which indeed it is: Acoustically rebellious, loud, cheeky and never boring. Shrill and out of control. Occiasionally inexplicably mystical and subtle.

Kawai S-100F / Teisco S-100F Synthesizer

The S-100F sound is always strong and succinct (a second important parallel to the ARP 2600, besides the tonal flexibility). Its sound sits at the very edge of the speaker, it doesn’t hide, it doesn’t weaken, it’s convincingly “present”, it rushes from one acoustic happening to the next.

To sum it up: Enormous tonal flexibility and sound presence – this is what makes the  Synthesizer-100F special among specialities.

Why the S-100F is still a “Terra Incognita” to many musicians is beyond us. It may be its name: “Kawai” … “Teisco” (if it were “Roland” or “Moog”, the story would probably have developed completely differently). Again, it may be that the lack of a proper CV/Gate port has deterred musicians from using it (today, however, this shortcoming can be solved quite easily). Or, it may be its unspectacular exterior. Essentially, this is a small synthesizer, not particularly “hip”, somewhat boring to look at, with no pitch-bender / mod-wheel and without arpeggiator / sequencer. But still … who cares?

Kawai S-100F / Teisco S-100F Synthesizer

From today’s perspective, this lack of reknown surprises. The S-100F is not just a “good”, it is an “excellent” instrument. Inconspicuous to look at, the Kawai S-100F / Teisco S-100F is nonetheless a goldmine for any synth-enthusiast. An instrument with high-end audio values, tonal flexibility and a thoroughly honest, powerful analog sound.

“Well, an ARP Odyssey can do all that (and more), too …” attentive readers might argue. Sure, that’s correct. But … ARP made a mistake, a big one. With the exception of ARP 2500 and ARP 2600, it used inferior hardware on all of its synthesizers. Main weak point: The faders. Thus, playing an original ARP Odyssey can be a rather joyless musical experience on stage or in the studio, mostly because of jagged faders. And then there are those rickety keyboards. Clunky hardware kills creativity within seconds …

Playing the Kawai S-100F / Teisco S-100F, on the other hand, is almost always a source of great joy. The faders – good quality – feel excellent and the keyboard is a pleasure to play, with no clattery noises on the side. Knob tweaking and sound research on the S-100F is a joy!

Kawai S-100F / Teisco S-100F Synthesizer

Kawai S-100F / Teisco S-100F Synthesizer

Nevertheless, the S-100F hardware has a weak point, too: Its “fake” wood. The synth has one of those cheap wood laminate cases often found in Japanese synthesizers. Well, it is THERE, so you’ll have to accept it.

Secondhand market

Clever synth enthusiasts are on the fast lane. If they’re smart, they’ll grab a Kawai S-100F / Teisco S-100F as long as those instruments are still cheap on the secondhand market. Currently, the Synthesizer-100F goes for a mere 800 to 1.000 Euros / USD. Regarding its flexibility, power and musical potential, it is worth at least twice as much. But times will definitely change, demands will rise, and with them prices will go up.

And should the occasional question arise: Teisco S-60F and S-110F are – by comparison – of completely different quality. Good and strong sounding instruments for sure, but somehow “mainstream” and a little boring. No VCO-to-VCF FM here, no pedal (VCF) input, no super-duper-fast envelopes, no weird modulation stuff. Well-built and good designed synthesizers of average musical quality, not more. And soundwise not “half” the power of the S-100F.

Kawai S-100F / Teisco S-100F Synthesizer

All in all …

The Kawai/Teisco Synthesizer-100F is still an insider tip among the analog classics. This rather boring-looking but grand-sounding experimental synthesizer can still be found on the used market on a regular basis – and at humane prices. Its harmless, unassuming appearance and its smallness may lead to the assumption that this is an instrument of no importance …

… which is not even close to the truth. In terms of sound, the S-100F reminds us of the grandiose ARP 2600. It convinces with ultra-dry basses, razor-sharp envelopes, an extreme range of audio frequencies, excellent effect sounds and much, much more.

The Kawai S-100F / Teisco S-100F, one of the last white spots on the “Terra Incognita” of synthesizer history, has no noteworthy cult status and is not particularly popular at present. We prophesize that this will change in the very near future.

Kawai S-100F / Teisco S-100F Synthesizer

30 minutes of sound samples are included. All sounds are from the Kawai / Teisco S-100F – with two exceptions: In “Mix 1” Studiologic Sledge provides some soft pad sounds. And in “Mix 2”, full of other synthesizers, there’s a clearly audible scratchy Roland TR-808 volume pot (we apologize) and a short, but great piano solo by Wolfi H. The sub-audio-bass: Kawai S-100F.

Filed under 2020, Main Feature, Reviews

“Es genügt, einen Ton schön zu spielen” sagte der Komponist Arvo Pärt im Jahre 2005. Diese Aussage ist ebenso einfach wie ich auch exzellent: Es braucht kein Meer an Tönen, denn entscheidend ist der Klang. Dass so mancher Vintage-Synthesizer der 70er und 80er Jahre teils unerreicht hochwertige Klänge liefert, steht außer Frage. Doch tatsächlich leben wir “heute” in einer nahezu perfekten Zeit. Einerseits hat man – mehr oder weniger – noch Zugriff auf die Vintage Analogen, andererseits wird auch bei Neugeräten die wichtige Komponente des hochwertigen Klanges wieder zunehmend berücksichtigt. Doepfer, Cwejman, Synthesizers.com, MacBeth, Moog, GRP, Studio Electronics, COTK, John Bowen und andere Hersteller bauen hervorragende Synthesizer, die den “Klassikern” in nichts nachstehen. All diesen (alten wie neuen) “großartigen” Instrumenten ist Great Synthesizers gewidmet. _________________________________________________________ In 2005 composer Arvo Pärt said: “Playing one tone really well is enough”. In other words, it is sufficient to play one tone 'beautifully'. I agree with that. All musical efforts are focused on the sound itself. Although I studied classical music (piano and drums), it’s the electronic sound that inspires me. Synthesizers are the epitome of new sounds and exciting tonal spheres. Today, many companies produce high-quality - excellent! - synthesizers: Doepfer, Cwejman, MacBeth, Moog, GRP, Synthesizers.com, COTK, Studio Electronics, John Bowen and others. It's their products I'm really interested in ... apart from Vintage Synthesizers, which I have been collecting for 20 years. Subsequent to our former websites Bluesynths and Blogasys, Peter Mahr and I have now created GreatSynthesizers. We hope you like it.


  1. I’ve had the Kawai 100 F since 1978, and it came with a bunch of preset cards – overlays for the various instrument sounds and effects – which went missing in a house move years ago. If anyone knows how I could get hold of a set I’d be very grateful! Thanks in advance :-)

    • Theo Bloderer

      … hello Daniel … I only have some spare “blank” overlays. Contact me if interested. Regards – Theo

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