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 Kawai S-100F

Kawai S-100F
also known as a re-badged Teisco S-100F



Kawai or Teisco S-100F

Hmm... 95000 Yen is a lot today.
Wonder what the exchange rate was back in those days. it was lower...

Well, it's true, the Kawai S-100F is the same as the Teisco S-100F. In fact they are the same company.
The 100F features:
- Single VCO monophonic analogue synth with a 3-octave, 37-note, keyboard.
- The single Osc can go from 2', 4', 8', 16', 32',64' to "Low".
- There are 2 ENV and an LFO, plus Portamento with a 3-MODE switch.
- VCF can be modulated by the LFO, Envelope 1, the external input, or the oscillator (sawtooth or square waveforms).
Basically this thing is about the same size as the Jen SX1000 or Moog Rogue, but it is one strange little baby. It does many strange things, but also it has some character. Afterall, this is no Moog, no Roland, no Yamaha.
It does have CV Gate in, (actually, rather ''CV IN''), but only on 1 single mono CV socket. Apparently, the Gate is controlled by voltage changes ?!  Also, the CV is a kind of reversed thing, lowest note is +4V, highest is +15V (!)
The are info on the web that Depeche Mode has used an S-100F on their very first track "Photographic", along with a Moog Prodigy, Yamaha CS-5 and a Boss DR-55 Drum Machine. 



S-100F and Me

Picked this one up on last year (2004).

They're not too rare nor too difficult to find, but they don't appear very often tho.

I actually quite like it, even tho it's weird. The way things can be modulated is not conventional, and it's always a bit adventurous to try see how this sounds or how that would sound.

Can spend a long time playing with it!

I suppose, what bugged me most (and everyone else who owns an S-100F) is the lack of a proper CV/Gate in. No Gate Input is already kinda strange, but reversed CV?!

Also on mine, there are 2 very strange things - I'm not actually too sure if it's supposed to be like that or not.
1. There is the VCO/Noise/External Audio 3 position selector switch, but if you select Noise, you only get noise, no VC mix.
2. The VCA Gain slider...
When it is turned up, the synth won't stop, it'll just sustain forever. Hmmm... maybe I should read the manual...

Other "strange" features ...
It has a HPF high/Low slider.... High Pass Filter after a quite powerful VCF.

When it first arrived to me, there were slider caps missing, but I have some similar ones so now all sliders are there.

But hey, I like this. It's not so common (as opposed to Roland SH-series) and the layout is surely not very conventional!



My S-100F when first arrived.
Some slider caps missing....




Above: taken when I first got the S-100F.
Below: more recent. Slider Cap replaced but ENV1 Attack is slightly bent.

Note about the PORTAMENTO A-B-C Mode Switch:
This is not a speed switch. It's a MODE switch. IN Mode A, it's like normal portamento. In Mode B and Mode C, portamento will kick in if notes are played overlapped (Legato). At Mode C, the ENV is also affected by the legato playing.

VCO Range rotary has 7 positions!
VCO can be modulated by Delay Vib. / LFO / ENV1 or ENV2

Many modulation options for the VCF too!!!
Above: taken when I first got the S-100F.
Below: More recent. Slider Cap for ENV1 mod replaced.

Yes, modded - you can see the MIDI/Learn..


On the left... yikes! That fracking flying mains cable hanging out....

Audio Input, then HIGH and LOW out.
Synth CV, the strange CV/gate all in one IN socket, plus a 'split synth' CV out.
All CVs are +4V (Low) ~ -15V (High).
There is also a socket to connect an Expression CV Pedal.



CV/Gate, Mods and/or MIDI-fying the  S-100F
Well, there's a Teisco Website run by this guy Sander Meyer. If one searches the Analogue Heaven Archive on 100F, you can see, someone has done the proper CV/Gate mod, and he's been asking for info on this but somehow no-one posted any info (even tho there are people who has done the mod and got it working).

I looked at the PCB, there is GATE labelled on the tracks. Then there is the CV IN Socket....

I actually did a few experimental CV boards, thinking, maybe if i can do a reversed CV, so it gives roughly +4V to -15V, it might work. Well, not much luck for me. Damn, my electronics' not that good...


A search on the web, I found that Kenton does do a socket kit, only that it's like £77 or something.
I emailed them to ask if this is a basic 3 sockets (CV/Gate/Filter kit) - if it is, then I won't get it, since I can test and eventually find out where things are!!
Kenton told me, no, it's not just sockets, it has a custom built board that takes care of that CV/Gate, hence its higher price than most
other usual socket kits.

Kenton's "Proper" CV/Gate/Filter Socket Kit for the S-100F

Well, I can tell you, it works! And it works pretty damn well too.
I highly recommend anyone wanting to add proper CV/Gate to get this Kenton socket kit. It's worth it.

I have taken some notes on what I have done with the Kenton sockets, plus MIDI-fying the S-100F.
For full details, please see the MOD PAGE.

bullet Mods1: General stuff - IEC Mains Socket, Fuse connections
bullet Mods2: Proper CV/Gate - The Kenton Sockets
bullet Mods3: VCF Cutoff CV In
bullet Mods4: MIDI fying the S-100F
bulletMods5: Other small mods (LFO Freq / VCA Gain)
bullet Mods6: Simple CV Range Amp
bullet Mods7: Possible Modular Sockets

Midi Equipped Kawai S-100F


To Do's (Maybe)
bulletMore Mods? Or more "Modular Sockets"? Looking at the Schematics, there are a few points where the signals could be patched out as modular outputs. See Mods7: Modular Sockets above.
bulletRemove the keyboard and Module-fy it or maybe even take it apart and rackmount it!

As of July 2005



Sounds of the Kawai S-100F

Some soundz... actually, these are more like dossing around with the modulation capabilities of the S-100F.
bullet LFO VCF
LFO pulsating, plus modifying the filter cutoff either by the Midi CC or LFO VCF Mod Slider, etc, can't really remember what I've done there...
bullet VCF Env1 Mod
VCF demonstration - first, just the filter cutoff, then the filter is modulated by the ENV1, varying the decay and randomly tweaking the cutoff as well...
bullet VCF VCO Mod
VCF modulated VCO - when the Resonance is turned quite high, it goes into a ring modulation type sound.
bullet Misc Modulations
Misc doss around...  damn, need to clean that cutoff slider!
bullet LFO ENV1 Mod 1
LFO Triggering the ENV1, then various decay & modulation options....
All those repeat pulsating rhythms are the LFO, not sequences.
bullet LFO ENV1 Mod 2
LFO Triggering the ENV1, then various decay & modulation options....
This is just messing about with a simple arpeggio sequence played from a sequencer.
Play ALL
These were recorded before I got the CV Range for the VCF Cutoff sorted out. So sometimes you'll here the slightly dirty noise from the VCF Cutoff slider (just a few dead spots that cracks a little).
I'll put up more some sound examples here when I have the time!! There can be many, since one can have hours of fun on this baby.



Other Links on the S-100F
bulletThe Teisco Website, run by Sander Meyer, has an S-100F info page.
bullet E-music DIY Archive has a Teisco page with schematics to download.
bullet Kenton - sells a "proper" Socket Kit for the S-100F, with proper CV/Gate and Filter sockets - highly recommended!!



Blue LED, heheh


C Y 's files on the Kawai S-100F

Click to Enlarge
bulletThe Schematics for the S-100F,
slightly coloured for easier viewing.



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