Archive for December, 2011


Alternative Keyboards 1

I’m not sure exactly which department this topic should go in, but I’ve added ‘Software/MIDI’ as the advent of these two things has made the possibility of using alternative keyboard layouts very much a practical proposition. I’ve been experimenting with these and come up with some relatively low-cost ways of trying them out.

The purpose of this post is to explain what ‘alternative keyboard layouts’ are – as opposed to ‘alternative methods of controlling synths’ or ‘alternative methods of generating musical notes’, which I deal with elsewhere in the blog. Although there’s undoubtedly an overlap between these things, I’d like to talk here about some specific proposals that have been made over the years to improve the traditional piano/organ keyboard – certainly appealing to those who are non-players of the instruments, but also with a specific appeal to trained keyboard players and those with a keen interest in music theory.

I’ll get into the music theory aspect, insofar as I understand it myself, later; and follow-up posts here will describe the different ways I’ve tried putting alternative keyboard layout ideas into practice.

To begin at the beginning, the conventional piano keyboard, with its line of large white keys interrupted by thin black keys, although a familiar and iconic design, isn’t necessarily the easiest way to play or learn to play music: you have to hold your arms at an odd, straight-on angle to the keyboard; it’s a long stretch from one note to the next octave up or down; you have to move your hands to different positions to play chords in different keys, and so on. Ultimately we might also consider how difficult it makes things if you want to play music using divisions of the musical scale which are different from the 12-note one we in the West are used to.

It was a long time ago, certainly as early as the 19th century, when people began to think of replacing the one-dimensional line of keys found on pianos and organs with a two-dimensional bank of keys, like the bank of keys on a typewriter (or this computer keyboard I’m using now).

It was quickly realised that there would be more than one advantage to this arrangement: notes could be repeated in several places on different rows, allowing the player to find the easiest way to play a particular passage (players of stringed instruments are used to this and wouldn’t want to be without it!); notes which are far apart on the conventional keyboard could be placed closer together, enabling even those with small hands to play chords or melodic passages with large intervals; and, most importantly of all, the keys could be distributed in such a way that the pattern of a particular chord would be exactly the same, no matter which key it was played in, and the pattern of a melodic passage would be the same, no matter which note it started on.

It is this latter feature which leads to the name often given as a description of this type of keyboard – ‘isomorphic’. Well-known isomorphic keyboard layouts were invented by Paul von Jankó and Kaspar Wicki in the 19th Century, and in the 20th Century, Brian Hayden independently developed a system similar to Wicki’s, which one often sees described as the Wicki-Hayden system.

This is a picture of a piano with a Janko keyboard layout. As you can see, there are still white notes and black notes, but not in the same pattern as on a conventional piano, and there are 6 rows of keys:


[Photograph of piano with Janko keyboard at the Musikinstrumenten-Museum, Berlin by Morn the Gorn (Own work) [CC-BY-SA-3.0 ( or GFDL (], via Wikimedia Commons’]

This diagram of the Wicki-Hayden layout shows how the notes are placed in relation to one another. The keys themselves may be buttons, as they are on a concertina or accordion (Brian Hayden was a concertina player), but the hexagonal pattern used here emphasizes the importance of diagonal relationships between the notes, and relates to the method often used in modern electronic instruments of using hexagonal keys set out in exactly this way.


[Diagram of the Wicki-Hayden note layout used on some button accordions and some isomorphic button-field MIDI instruments by Waltztime (Own work) [Public domain], via Wikimedia Commons‘]

You can read about the Janko, the Wicki-Hayden, and a number of other isomorphic keyboard systems in the Wikipedia at:

Each of these pages contains numerous links to external sites, if you’d like to know more. I’ll be dealing with some of the issues that follow on from this, such as microtonality (as mentioned above, these two-dimensional layouts also lend themselves more readily to musical scales of more or less than 12 notes) and dynamic tonality in future posts.

You should also check out this site: which is also the home of the program MIDI Integrator, which I have used, and an interesting modern-day electronic instrument using an isometric keyboard (two, in fact) called the Jammer.

The Jammer, in turn, is a development along similar lines of an instrument called the Thummer – which almost reached the point of commercial production – and uses a keyboard called the AxiS-49, which is commercially available (from C-Thru Music at A larger version of this keyboard, the AxiS-64 is also produced:

All of these instruments these days are MIDI controllers, and YouTube is probably the best place to see them in action. This lengthy introduction to the AxiS-64 also serves as an illustration of many of the reasons why isomorphic keyboards were invented: You can also see the Thummer and the Jammer

There are hundreds more videos of these instruments and others, including a nice-looking Japanese synth called the Chromatone, which appears to be completely self-contained:

The next post in this department will be on methods of creating simple isomorphic keyboards, and the hardware and software I’ve used to create mine.



I must say I’m very fond of Stylophones!

The Stylophone, if you’ve never encountered one, is a small, hand-held monophonic instrument played by touching a stylus to a row of metal pads – the edge of a large printed circuit board – laid out like the keys of a piano. It was invented and first marketed in the 1960s, and is sometimes described as the world’s first mass-produced synthesizer.

In my view the Stylophone is an indispensable element in the arsenal of the electronic musician – it’s simple, distinctive-sounding, and most types are available at a reasonable price, with patience, from charity shops or on eBay. It’s also possible to make a number of straightforward – and some not-so-straightforward – modifications to it. I have described elsewhere in the blog some of the ones I’ve done.

Although largely the brainchild of engineer Brian Jarvis, accounts of its genesis in 1967 suggest that the Stylophone would never have seen the light of day without the encouragement and input of brothers Burt and Ted Coleman who, together with Jarvis, ran a company called Dübreq. Dübreq produced equipment for the film and broadcasting industry and their name is said to derive from their specialities of DUBbing and RECording, with the umlaut and the ‘q’ added to give the firm more of an international air (or perhaps, like Motörhead or Mötley Crüe, just to look cool!)

The marketing masterstroke which ensured the eternal popularity of the Stylophone was the engagement of the multi-talented London-based, but Australian-born entertainer, Rolf Harris. Even before production began, the Stylophone was introduced to the world on Harris’s popular Saturday TV show on the BBC, and, it is said, became an instant hit – despite at first being available only by mail-order from Dübreq at the frightening cost of 8 pounds 18 shillings and sixpence, around ninety-five pounds in today’s money!

Over the following decade a number of different versions of the Stylophone were produced. I have a treble – which is all white – a standard black, and a bass – also black. This latter wasn’t a production model, but the circuit diagram that came with the standard showed different component values for all these three types, so I modified a standard to produce the bass register, an octave below. I’ve subsequently modified this to produce a further octave below that – I call it ‘The Double Bass’ – but this is not a modification suggested by Dübreq themselves.

This is a circuit diagram of an early Stylophone. Note the details of alternative components: resistors in the top left and capacitors in the bottom left.

Stylophone schematic 2

There is also a later 1970’s version (the ‘New Sound’) with a fake wood fascia in place of the familiar metal grille. This latter has a feature noticeably absent from the earlier models – a volume control, a useful feature in the days before the ubiquitous earphones. Here is the component layout and schematic/circuit diagram from the booklet which came with it.

Layout and Circuit Diagram

It was not long after this, in 1975 or thereabouts, when production of the original Stylophone ceased; and this might have been the end of the Stylophone story, had Brian Jarvis’s son Ben not had the idea in the early 2000s of bringing it back. By 2007 the new Stylophone S1 was on sale, sufficiently similar to the original to be instantly recognisable, but with some updated features, including built-in input and output sockets and a three-way tone control.

Stylophone S1 2sm

It’s possible to do modifications on all these variations on the Stylophone design, even the S1. Despite the fact that the chip that does all the work in the S1 is very tiny and inaccessible, parts of the pitch and vibrato circuits are available, and the output stage is on a separate PCB. I was able to do some mods on a couple of these.

The ‘New Sound’, based on the very common 555 chip is easier to deal with, and I was able to do a lot with mine (see There are many circuits for 555-based oscillators in books and on the internet, and the 555 in the ‘New Sound’ is easily accessible for modding.

I haven’t done much with the original Stylophones – but these should be even easier, as the resistors which fix the pitches of the notes are exposed, and it should be possible to do things to these without too much trouble.

The biggest problem with the original and ‘New Sound’ Stylophones is likely to be the cost. Since these are sought after by collectors, they can fetch rather higher prices than you might want to pay for something which you intend to experiment on!

Many stars – other than Rolf Harris himself – have been publicly associated with the Stylophone. You can read about these on the Stylophone page in the Wikipedia at, and see pictures of them on Stylophonica, ‘the official home of the Stylophone’ at You can also learn more of the history of the Stylophone at (or, the Stylophone Collectors Information Site; buy a vintage Stylophone at, the Stylophone Sales Center; or even make your own Stylophone at!

You will also find out about the mighty Stylophone 350S, much larger than the ordinary Stylophone, with two styluses (styli?), more notes, more tones and a cunning light-sensitive filter/vibrato control. This also went out of production in the 1970s and has not so far been revived.

Stylophone 350s

These machines – wonderful thought they are, as you can see – can be seriously expensive, and you would probably want to think twice about having a go at the electronics in it without knowing what you were doing. Having said that, like the conventional Stylophones of the period, the electronics will be relatively straightforward compared to modern devices. A bit like cars, really – in the old days it was much easier for the amateur home mechanic to sort out engine problems: nowadays, there’s very little you can do. The 350S has many different ‘voices’ and that intriguing photocell circuit . . . there’s got to be some scope there.

A new type of Stylophone that has appeared in recent years is the Stylophone Beatbox: a drum machine playable – of course! – by means of a stylus, including percussion, vocal percussion and bass sounds, and able to record and replay sequences. I have some functioning ones, which may also be good for circuit-bending, and some non-functioning ones from which the attractive circular playing surface should be useful for other projects.


I used the case and the keyboard PCB of one of these for a Stylophone project, but not the sound-producing electronics as there were faults with the ones I acquired which I couldn’t fix.

Dübreq’s website at suggests there are more Stylophone products in the pipeline, but none, at the time of writing have appeared. Some other websites have been advertising the imminent arrival of the ‘Stylophone Remixxer’, but I’m not aware of any genuine sighting of such an object.


The Superstylonanophone

I wasn’t intending to get into MIDI instruments at the time I started on this project, and construction of the Superstylonanophone came about by accident when I acquired an apparently non-working Korg Nanopad.


Essentially, what it is is a cut-down Nanopad attached to a Stylophone, so that the middle 12 keys of the stylophone operate what would, in the Nanopad, have been the 12 pads.  The touch sensitivity of the original pads seems to have all but gone, which is a big loss – but the pads didn’t work at all on the device I acquired, so the present arrangement is an improvement on that.

I have since learned that stuck pads is a common fault in Nanopads, and there is currently an instructional video on YouTube at, uploaded by treilaux,*  telling you how to fix them.  If you have a Nanopad with stuck pads, you could do that instead of what I did; even if you don’t, you can see from that film how I took the Nanopad apart and detached the pad section from the electronics section.

*[Edit: this video disappeared for a while, but it’s back now.  While it was away, this note said try this one uploaded by TechinWorship, which details the same procedure, at:  As the intro to the video says, ‘Often times the trackpad will be responsive but the pads will not. This is due to normal wear and tear over time that causes the sensors to become jammed within the hardware. If this happens to just one of your pads, all will become unresponsive. Opening up your Nanopad and separating the sensors often returns your MIDI controller to like-new condition.’]

I continued by sawing off the large right-hand section of the Nanopad with the pads in it, and was left with just the circuit board, ‘Scene’, ‘Hold’, ‘Flam’ and ‘Roll’ buttons and the track pad.  I trimmed down the back as well, to fit the remaining piece of Nanopad front panel.

Nanopad 1

Everything was removed from inside the Stylophone (it was no longer working), except the PCB with the keyboard on it.

The difficult bit was connecting the Nanopad PCB to the Stylophone PCB.  This was not difficult in principle, but only in practice.  The Nanopad pads were operated by a plastic film connected to the PCB via a 14 way ZIF socket.  The connections on the PCB were too small for me to get at – just 1mm apart – so I was hoping to find a replacement 14 way jumper cable that would be long enough to go from the ZIF socket, out of the new Nanopad enclosure into the body of the Stylophone.

I couldn’t find one: it wasn’t a proper ribbon cable, but another thin plastic thing, and in the end I had to get a short one and solder a proper ribbon cable to another ZIF socket at the other end of it.  I managed to find a type with alternate pins pointing in opposite directions, giving me 2mm space between each one.

The other end of the ribbon cable attached to the backs of the 12 middle keys on the Stylophone PCB.  I chose C – B because these are the defaults for the Nanopad’s Scenes 2 – 4, which resemble a conventional keyboard.  You can change this with the Korg Kontrol Editor program, but there seemed no point.

The 14 lines from the Nanopad PCB to its pads were one connection for each pad, plus 2 control lines, one for the top row of pads and one for the bottom row.  I was gambling that these two control lines were, in fact the same, as the Stylophone’s stylus has only one wire going to it and I obviously wanted to be able to play all 12 notes.

Fortunately, I was right, so in the end only 13 connections were needed.  However, since the Nanopad is polyphonic, it seemed a bit of a waste not to take advantage of this, so I added a socket on the side for a second stylus.  This is connected to the same spot on the circuit board as the integral stylus.  After using the Stylonanophone for a short while, I realised that this is a great asset, especially for playing drums and percussion, even if only one note at a time is sounded.

Because foot controls would be more natural for some applications (e.g. bass drum and hi-hat, or bass pedals) I added an external socket for other input devices to connect to, giving access to all 12 notes.  I’ll be writing in more detail elsewhere about the switching systems I’ve devised, and later on in the blog about any of the input devices I’ve been working on, as and when they get finished.


The Nanopad doesn’t have MIDI in and out connections: instead, it has a built-in MIDI interface, and requires only a USB cable.  To allow for the possibility of future expansion (for example, I also have a Nanokeys I plan to work on), I decided to add a USB hub.  I found a flat square one that fitted into the base, and didn’t interfere with the vast amount of wiring inside the Stylophone body.  I superglued this in place.  The Superstylonanophone connects to this hub with a very short mini-USB to USB A cable, and the hub connects to the computer with a longer one.  The hub has proved very useful when I’ve needed to plug in more USB devices.

The Superstylonanophone logo, by the way, is just printed on a slip of paper tucked into the edging of the Nanopad trackpad.  This is easily removable, but isn’t thick enough to prevent the trackpad operating properly.  This was something I also saw on YouTube, at, uploaded by meltdownband.*

*[Edit: oh, dear – this video isn’t available either.  The procedure for adding the logo is very simple, though: just draw or print it on a piece of paper slightly larger than the visible trackpad and push the edges under the white plastic trackpad edging.  An ordinary thickness paper, like a printer or copier paper shouldn’t prevent the trackpad being used in the normal way.]


There are no sound files to go with this instrument, as it’s a MIDI controller, and can be used with any real or virtual MIDI instrument.

See this post for details of the foot controller I made to go with the Superstylonanophone.


The Big Boy – Mod 4

[Edit: the BigBoy, alas, is no more!  I irreparably damaged the  circuit . . . but now it lives on in the BigBoy Beatbox, which is described here].

Big Boy verticalsm

The creation of the Big Boy came about as the result of the blindingly simple, though ultimately pointless idea of transplanting the workings of a Stylophone into the body of a Stylophone Beatbox.

I had a number of broken donor Beatboxes, and proceeded to dismantle one of these.  There are 12 ‘keys’ on the circular board, laid out in a similar way to piano keys, or the keys of a Stylophone, so one octave was available.  I decided there should be three octaves, so had two challenges: one, to connect the Beatbox keyboard to the Stylophone keyboard; two, to add switches to change octaves.

Connecting the two boards together proved fairly simple.  FirstIy I had to saw off the end of the Stylophone board to make it fit into the Beatbox case, and although this made it impossible to use the higher notes, there were still at least 12 left.  So I used the lowest 12 keys, soldering one end of a wire to the middle of each key on the Stylophone board, and the other end of the wire to the connection on the edge of the Beatbox board for the appropriate key.  It was easy to see which key on the Beatbox board led to which connection on the edge.

There are also two built-in switches on the main Beatbox board, operated by depressing either side of a plastic ring around the keys.  I also made connections to these, for later use.

The existing on/off switch was used, with its associated LED, and the space taken by the 3 way slide switch used for selecting the drum, bass or vocal beatbox modes was used for the Stylophone 3 way tone switch.  The Beatbox stylus was attached to the place on the Stylophone output board where the Stylophone stylus had been attached.

I carefully removed the Stylophone tuning pot and used it to replace the Beatbox tuning pot on the small board which is attached to the inside of the base of the Beatbox.  One end terminal of the pot was attached by a wire to the place it was originally attached to on the Stylophone board; the centre terminal was connected to +V at the same place on the Stylophone output board as the stylus, via a series of preset potentiometers, as described below.

The preset potentiometers were designed to produce the three octaves.  If there had been room for a 3 way rotary switch in the body of the Beatbox, this would have been simple.  But there wasn’t.  There was room for a three way miniature toggle switch of the ON-OFF-ON type, so I decided to use one of these.

With a simple 3 way switch, it would just have required three presets, each adjusted to produce the same note in different octaves; but with the 3 way toggle it required the middle terminal to be permanently connected, and the other two pins – representing the switch in the ‘up’ or ‘down’ position – to be in parallel with the middle terminal resistor.  This proved quite complicated, and many adjustments were required before the 3 octaves became available.  The Stylophone functions in such a way that the lower the resistance, the higher the pitch.  As the rule about two resistors in parallel means that their combined resistance is always lower then the resistance of the lowest of the two, the middle position had to be the lowest octave, and the ‘up’ and ‘down’ positions had to be two octaves higher and one octave higher, respectively.

The integral switches on the board, operated by the plastic ring, duplicated the function of the toggle switch, allowing for momentary octave changes when either the left or right switch was depressed – this only really worked when the toggle switch was in the middle, ‘off’, position, but that was the most practical setting for most uses, I found.

An extra 10k resistor had to be placed in series with the stylus connection, to ensure that the correct pitch could be achieved with the tuning pot roughly in the centre of its travel.

Big Boy horizontal rearsm



Circuit bending is rather nicely described in the Wikipedia (at as the ‘creative customization’ of electronic devices such as ‘low voltage, battery-powered guitar effects, children’s toys and small digital synthesizers to create new musical or visual instruments and sound generators’.

The true method of approaching circuit-bending (IMHO, as they say) is experimental, without having – or without deliberately using – knowledge of the circuit you’re working on; the enjoyment of chance discovery is an important element of the experience, which is why I have distinguished it in my projects from ‘modification’, where I felt a knowledge of electronics and the circuitry being worked on was a useful thing.

The guru of circuit-bending is Qubais Reed Ghazala (, and his book Circuit-Bending : Build Your Own Alien Instruments (pub. Wiley, 2005, ISBN 978-0764588877) is the standard work on the subject.  It explains how he came to discover the idea of ‘bending’ – leaving a small, battery-powered amplifier in a desk drawer, the power on and the back off, where a metal object in the drawer touched parts of the circuit and produced marvellous noises – illustrates some of the instruments he has created over the years, and gives detailed instructions on how to ‘bend’ some popular electronic instruments and toys available today.

If you’re not able to obtain a copy of Reed Ghazala’s book, you can read about it on his website at, and follow a step-by-step tutorial at

A fabulous website for electronic music fans is; in this case a browse through their Circuit-bending forum at will throw up heaps of advice on what devices to get and what do with them once you’ve got them.  This may at the outset involve only making sure it’s using batteries, not plugged into the mains, switching it on, wetting your finger and poking the circuit board until something interesting happens.

So, if you’d like to get into electronic music, but are put off because you know nothing about electronics, then circuit-bending may be the thing for you, as Ghazala emphasises the fact that no knowledge is required!  Right at the beginning of Chapter 1 of his book he tells the story of taking his first circuit-bent instrument to school, ‘synthesizing birds, helicopters, and police sirens on the instrument, and running electricity through several people at a time so that we could play the device by touching each others’ bare flesh.’  His teacher is very impressed, looking at the dials and switches and hearing the extraordinary sounds.  ‘Mr Ghazala,’ he says, ‘I didn’t know you knew anything about electronics.’ ‘I leaned forward’, Ghazala tells us, ‘looked him straight in the eye, and said, ‘I don’t.’

At the time of writing I haven’t begun any of my planned projects in circuit-bending, but I’ve been collecting some suitable devices to work on.  I’ll report on these as soon as I’ve been able to get started; in the meantime, here are some of the items I’ve acquired.  I’m particularly interested in the human voice in this context, so you will see a Texas Instruments ‘Speak and Spell’ amongst them, a Vtech ‘Alphabet Apple’ and a Casio SK-60, famous for its ‘human voice’ presets.




Software and MIDI

If you’re interested in using computer software for making musical instruments or sound manipulation, there are several programs you can use, but my favourite is Pure Data.

The reasons I like it are:

1.  You can do a lot of different things with it

2.  You program it graphically, not by writing lines of text

3.  It’s free

4.  There’s a lot of help available, and a lot of people using it who are happy to share their experiences, and applications (or ‘patches’) they’ve written with it.

Another feature of the program, which I have not used myself, but which you might like, is its ability to handle graphics and video, and integrate these with sound.

You can read about PureData at, and also in the Wikipedia at  This is what Pure Data programming looks like:


This example shows MIDI information and audio information being used together as Pure Data can deal with them both.

From the Pure Data website, you can access manuals and tutorials, and a very helpful series of video lessons.  These are also on YouTube: just search under ‘Pure Data’.


The most practical version to use is ‘Pd-extended’, which you can download from here:  I use a Mac, but the program is also available for Windows and Linux.

[Edit: I believe that since I wrote the above, Pd-extended is no longer being developed, so you may consider using the unextended Pd ‘vanilla’.  I assume there is a straightforward way of adding the kind of features which Pd-ectended contains].

Another program for general use is MAX/MSP, which is very similar to Pure Data – in fact, it was invented by the same person, Miller Puckette.  The version you would use to create programs is not free, but the version you would use to run other people’s programming – ‘Max Runtime’  – is free.  It’s described at and can be downloaded from the Cycling 74 website at  There are Mac and Windows versions there.

Other programs I’ve used in this series of projects are to do with different methods of note input – in other words, programs which can interpret input from a QWERTY keyboard, a mouse, joystick, gamepad, etc., and allow you to use it for musical purposes.  These devices are collectively known as HIDs or Human Interface Devices, and programs such as Pure Data and MAX/MSP can readily be set up so these HIDs can be used as musical instrument controllers, just like a MIDI keyboard.

I’ve also used:

MIDI Integrator (a MAX/MSP application), which is an easy and efficient way to set your computer up to accept input from keyboard, mouse and so on and use them as MIDI controllers.  The program is described at and can be downloaded for free from there.

MIDI Integrator Screenshot

In fact, that website, ‘altKeyboards’ is a mine of information about alternative keyboard layouts, which I intend to write about separately at some point.  It’s well worth looking at this page to see what inspired author Ken Rushton (‘MusicScienceGuy’) to create MIDI Integrator.

Another MAX/MSP-based application is Alexander Refsum Jensenius’s ‘MultiControl’, which is able to recognize input from HID and convert the signals to MIDI output.  You can read about it and download it from here:


And finally, a program which is very good, but not free and available for Mac OS only, is ControllerMate.  ControllerMate is a very flexible and detailed program for customising input from of all kinds of HIDs.  It allows you to assign particular functions to all the buttons and controls on a device such as a keyboard, mouse, joystick etc., and to set up different named configurations – including multiple configurations for the same device – to make it quick and easy to use them for different purposes at different times.  ControllerMate is described at, and can be purchased from there.


These are the programs I’ve found most useful so far.  I’ll describe them in more detail when I report on the projects I used them for.


The Gemini – 3rd Mod

I was apprehensive about my third project, my final Stylophone mod for the time being, since it involved major surgery to two individual Stylophones, and I wasn’t really sure at the outset whether it would work.  In the end, in an unpredictable way of its own, it did!

The concept was simple, to generate two notes at the same time, using two Stylophone circuit boards operated by one stylus.  The ability to tune the fundamental note had to be retained, as well as means of selecting any harmony note – and, of course, it had to be possible to play the Stylophone as originally intended.

This photograph shows the main pitch control of the Gemini, the dual concentric potentiometer at the back left, as well as the fine tune, volume and blend controls on the back.  It also shows its decoration with signs of the zodiac stickers – I think the sign of Cancer (not visible) is the wrong way round, but this is not my fault, it was like that when I bought them.

Gemini high angle standard knobs sm

The first extra control to be added would be a 3 way rotary switch, to select ‘Normal’, ‘Harmony’ and ‘Modulated’ outputs.  This is just visible on the right hand side of the picture above.  ‘Normal’ would switch only one of the boards in circuit, with a mono output available to the internal speaker or to the headphone output; ‘Harmony’ would switch both boards in circuit, with one board available to the internal speaker, but both boards available to left and right sides respectively of the headphone output; in ‘Modulated’ mode, the outputs of the two boards were connected by diodes to allow the tones to interact with one another.

A dual 10k lin pot was used as a ‘Blend’ control, ranging from Board One (Oscillator 1) only to the left, and Board Two (Oscillator 2) only to the right, with varying mixes in between of the two tones produced.  A dual 10k log pot controlled the overall volume.  These were located in the circuit in place of the existing volume controls and both original volume pots and associated circuit boards were removed.

Pitch was to be controlled by a dual 500k concentric pot, the inner control for correct tuning of the fundamental pitch, the outer control for the harmony note, the interval being set by ear.  As this pot would cover a wide range, and the fundamental note would be difficult to set precisely, I decided to add a 10k lin pot, normally in centre position, in series with the inner pot, as a ‘Fine Tune’ control.

The first problem was to test if removing one stylus and connecting the ‘keys’ on one board to the corresponding keys on the other board would successfully enable one stylus on one keyboard to create two distinct notes at the same time.  Connecting the keys was easy enough, as each one has a small point – presumably included for testing purposes at the factory – to which wires could be connected.  To my relief, this procedure worked, two notes were produced simultaneously, and the interval set remained steady along the length of the keyboard.

The Stylophone’s original 3-way tone switch, as I had discovered on my first modification project, is a two-pole type, with only one pole used; so it was easy to connect the three wires from the two boards to other side of the same switch, to ensure the same tone was used on both boards.

I hoped the same would be possible with the vibrato, and connected the main boards together at the 3 inputs to the small board containing the power and vibrato switches.  This worked, too, and enabled one power on/off and one vibrato on/off switch to be used for both main boards.

It was the ‘mp3’ input/headphone output that caused difficulty, and I didn’t fully resolve this problem, I just got round it in a not entirely satisfactory way.  I had hoped that the outputs of the two amplifier boards would simply appear separate and equal at the headphone socket, and that a stereo input would appear as a stereo output.  (A stereo input is normally reproduced in mono through the internal speaker and the headphone output, as an unmodified Stylophone has only one mono amplifier in it).

I disconnected one of the mp3 inputs and one of the headphone outputs from Board One and replaced them with an input and an output from Board Two, in order to make this happen, but it was clear that one of the channels was leaking into the other one somewhere and the output was still mono, even though using two amplifier boards.  I had removed the 3.5mm sockets from Board Two, in order to fit this in the original case on top of Board One – maybe this had some effect on the stereo image, I don’t know.  But I eventually created a slightly stereo output by putting a 1k preset into the output of one channel, so Oscillator 1 was slightly to the left in the headphones, and Oscillator 2 slightly to the right.  This was the effect I was after in the first place, it just wasn’t the way I anticipated achieving it.

However, this was close enough to what I set out to create, so I considered the job done.

The following diagrams might help illustrate what I did and how I did it:

Gemini  Board 1b smGemini Board 2 sm

As it turned out, the pitches of the two oscillators couldn’t be set independently – raising the pitch of one would automatically lower the pitch of the other, and vice versa!  Not only that, but as the 500k pots were logarithmic the pitches would vary at different rates.  This apparent disadvantage, I decided, would be turned to an advantage – and would, in fact, be the whole point of ‘The Gemini’: the careful adjustment of the three pots to obtain a suitable pair of notes would become its principal performance feature.

The stylus, of course, was still fully functional, so as soon as a suitable interval was stumbled upon, this was playable up and down the keyboard.

Fitting everything back into the case was not easy, and involved quite a bit of rewiring to reduce the tangle of leads inside.  I had hoped to be able to fit everything in the original Stylophone case, but it soon became apparent that this wouldn’t be possible, so I aimed to deepen the case, as I had with ‘The Hedgehog’ – although not so drastically, as there would be fewer extra controls to add.  In the end doubling the depth proved adequate to contain the extra boards and wiring without unduly squashing them.  The extra piece of bodywork added to the case proved an ideal base for the zodiac motif stickers I added.

In use, the basic pitch seemed somewhat lower than originally intended, but it turns out that ‘The Gemini’ is perfect for bass sounds, and some excellent tones are obtained, especially in ‘Modulation’ mode.


The Hedgehog – my 2nd modification

My second modification, and first variation on a classic theme, was initially described by its inventor, Forrest Mimms III, as a ‘Sound Synthesizer’, and later as a ‘Stepped Tone Generator’ before it acquired lasting fame as the ‘Atari Punk Console’, or APC for short.

The APC consists of a pair of oscillators, using the ubiquitous 555 timer i.c.: one ‘astable’, or continuous, the other ‘monostable’, triggered by the first.  The 556 is often used, as it contains two 555s in one chip.

The design is so famous, it even has its own page in the Wikipedia.

I remembered that one of the Stylophones in my collection, the 1970s ‘New Sound’, was based on a 555, so decided this could be adapted as the first oscillator in the circuit.

This is what the ‘New Sound’ Stylophone looks like:

Stylophone Parts sm

And this is the circuit diagram from the booklet that came with it:

New Sound Stylophone Circuit Diagram sm

Looking around at various implementations of the circuit, I decided an LFO would be a handy addition, so decided to add a 556, to give 3 oscillators altogether.

I designed the circuit in my usual way by drawing, photocopying, erasing, cutting, and sticking, and ending up in this case with a very large piece of paper that had to be laid out on the floor to be read.  This is a photograph of the finished design:

270111 002 med

The middle part of the diagram is part of the Stylophone circuit.  The other parts were mainly inspired by Forrest Mimms’ own description of the stepped tone generator at, the ‘Blast Fed Disaster’ from, and the article at, including the Datura Mod.

As far as I recall, the 680Ω resistor shown in the circuit diagram as R8, where the circuit was broken for SW1B, wasn’t actually there and was replaced by a wire link in my Stylophone.

In the end, there were very few components to add to the Stylophone, just lots and lots of pots and switches, and yards of connecting cable.  The 556 and one or two other components for decoupling were on a small piece of veroboard, and took up very little room, but the biggest problem I had was to find enough space inside to fit the extra circuit board and all the wires in, and enough space on the outside to attach all the switches and knobs.

It was clear from the start that the Stylophone case was far too small to contemplate this.  I didn’t want to add a break-out box, or disfigure the Stylophone too much by sticking extra boxes to the side of it, so I decided to extend the depth of the case to create more room.  I bought some small pieces of 2mm acrylic, to match the thickness of the original case material, sprayed it black, drilled holes and stuck it in place.

It was now more than twice the height of the original Stylophone.  Still not deep enough.  A couple more centimetres all round of brown acrylic vaguely the same colour as the original ‘natural wood’ finish on top, and it was as deep as it was wide, with switches and knobs poking out on all sides.  This is how it acquired its nickname, ‘The Hedgehog’.

This low-angle shot of the considerably enlarged case of the ‘New Sound’ Stylophone shows most of the controls added to it to create ‘The Hedgehog’.

Hedgehog low angle 1 sm

The three on/off switches and potentiometers on the left, controlling Oscillator 1, are duplicated on the right-hand side for Oscillator 2, as are the two small touch points above.

Hedgehog inside 1 sm

It took some days to connect all the wires, and jam everything into position, but when I finished, much to my surprise, most of the functions worked straight away!  First of all, with the 3-pole SW1 (‘Keyboard off’; upper switch, front left) and the double pole SW2 (‘Oscillator on’; lower switch, front left) switches both in the ‘up’ position, the Stylophone was able to function normally; with the ‘Oscillator on’ switch down, notes played with the stylus could interact with the second oscillator; with both switches down, the stylus is not used, and the instrument is ready for full ‘Punk Console’ mode.

Classic ‘stepped tone generator’ effects can be produced with the middle switches on each side down, putting VR1 and VR3 in circuit.

Using the other switches on the sides, VR4 and VR5 alter the pitch or timbre of Oscillator 1 (the Stylophone oscillator); VR2 and VR6 can be used to alter the pitch or timbre of Oscillator 2, and thus radically affect the overall nature of the output.  The pitch range of both oscillators can also be altered by selecting one of 6 capacitors for each.

The third oscillator is configured as an LFO, connected to the control voltage input of oscillator 2, and thus affecting its pitch.  There are two sets of 6 capacitors associated with the LFO, and a variable potentiometer, which control its speed and depth (visible in the first picture above).  These controls actually enable it to move up into a similar pitch range to oscillator 2, creating some frequency modulation-type effects.  The Stylophone’s original vibrato is still available to oscillator 1.

The LFO is particularly effective when used in conjunction with the two controls on the back of the instrument: ‘starve’ (right of the picture below) – reducing the supply voltage available to the oscillators – and a flashing LED, which produces a slow, steady fluctuation in pitch (centre of picture).  Both of the pots have integral on/off switches.  A steady LED indicates when the starve control is on, and dims as the voltage decreases.  The knob on the left of the picture controls the brightness of the flashing LED, and thus the amount of effect it has.

Hedgehog high angle back sm

Also visible in the picture is a 2.5mm power socket, installed many years ago before rechargeable batteries became common, and before this series of modifications was planned.

The three feedback controls on the front are ‘on-off-momentary’ switches, which are sprung to return to centre (off).  This makes it a little easier to apply a short burst of the effect by raising the switch and letting go, rather than flicking it down, then up again.

The Stylophone is intended to be tuned in the following way:

Tuning sm

The tuning control has been extended with a length of plastic tubing so it still protrudes through the casing underneath and can be used as originally intended.  This can be seen in the picture of the inside of ‘The Hedgehog’.

The original base of the Stylophone was replaced.  It was not glued in position as it has to be opened in order to replace the battery, a 9v PP3 type.  The battery leads were extended in length to reduce strain, due to the longer distance between the circuit board and the battery compartment.

Playing ‘The Hedgehog’ is always a delight.  Because of the wide variety of interactions between the oscillators, the amount of adjustment that can be made, and the lack of any labels to remind you what each of the controls does, successive sessions are rarely identical.

Playing the Stylophone

Here are links to the sound files for ‘The Hedgehog’.

The first one is an extract from a track on my forthcoming album, slightly remixed to feature The Hedgehog’s contribution:

For hard-core electronic noise fans, the others are a slightly edited 15-minute improvisation – one long piece, but divided into 5 sections to make the files shorter, and because the different parts have a different feel to them:


The Hedgehog is a mono instrument, so I’ve added a stereo spread plug-in to the recordings (made in Logic) and some reverb.


The Alien – my first modification project

My first Modification project involved a Stylophone – the 2007 re-issue – which I modified as shown below:

Stylophone labelled

1.  Power on/off.  This is the original power switch, unchanged.

2.  Drone switch.  The original vibrato switch with different wiring connected to it.  This switch causes the Stylophone to sound without using the stylus – useful in conjunction with some of the other modifications for which you need free hands.

For anyone interested in the details, I didn’t manage to document the whole procedure, but I’ve got a couple of pictures of the inside.  This one shows the end of the main circuit board and the small board for the power on/off and vibrato switches.


The original wires to the vibrato switch were disconnected, but not the other wire to the small circuit board, which goes to the Power switch.  As it’s a three-way cable, it might be easier to disconnect all of them, bend the two vibrato wires out of the way, and then reconnect the other one.

The pole of this switch (the middle of the three tracks) was attached to the highest note on the keyboard.  Each note has a small round spot where a wire can be connected, and you can see the spot for this note nearby on the keyboard circuit board.  The ‘on’ end of this switch is attached to the point where the stylus wire is connected to the third circuit board inside.

(In the picture, where it says ‘connect the end one to the end of the stylus wire’, it means the end track on the circuit board, not the end of the wire itself, which is going to be used for something else later.  Note that both these switches are SPDT, but used as SPST, with one end not connected).

3.  Tone.  This is the original 3-way tone switch, unchanged.  It’s a double-pole switch, with only one side used, so there ought to be plenty of scope for adding functionality to it.  I tried adding momentary switches linking the three wires that go back to the circuit board, for brief tone bursts, but in the end didn’t leave them in as it was hard to find one that worked in each of the three tone settings.  Adding potentiometers didn’t seem to have any effect.

4.  Feedback loop.  This switch and potentiometer are wired to two places in the output circuit of the Stylophone.

The switch turns Feedback on, producing a continuous high-pitched sound, adjustable by means of a 220k Log potentiometer.  When using the stylus with this circuit on, very interesting tones are produced as the feedback tone modulates the note played with the stylus.  In Drone mode, a ‘double’ tone is produced, very rich in harmonics.

Once the feedback wires are attached to the circuit, even with the switch off, a hint of the high-pitch breaks through to the output, and there’s a hint of the modulation when notes are played with the stylus.  Apart from this one effect, ‘The Alien’, as it is known, can be used with all the switches off as a normal Stylophone, with variable rather than fixed vibrato.  Feedback is such an effective tonal modification, though, I didn’t want to leave it out.

5.  Wide-range pitch control.  This is a 2.2M Log potentiometer which allows the pitch to be changed from a very high note, to a very low note – so low, that it hardly seems a pitch at all, almost a beat.  Can be useful!

6.  Pitch Effects on/off.  This switches the Stylophone’s pitch control out of the circuit as well as switching on the modified pitch effects.

7.  Wide-range pitch control on/off switch.

These 3 controls were the most difficult to arrange, especially as I wanted the Stylophone’s original pitch control to be used as normal when it wasn’t switched out of the circuit by 6.  This meant breaking the original connections to the pitch potientiometer and putting in some new ones.


The other difficulty was that the Stylophone doesn’t mind going right down to a very low pitch, but doesn’t like going up too high.  If you try to make it go too high, it will cease sounding and you can only get it to work again by switching off and on, or in some cases switching off, removing the batteries, putting the batteries back in and switching on again.  This is a common phenomenon in circuit bending, but I didn’t install a battery cut-out switch, as is often done – there’s no need for this to happen, even with all the modifications working, so it could be designed out.

Accordingly, the wide-range pitch control doesn’t go all way from + v to 0v, but is connected to +v by a variable resistor, enabling you to set the highest note it will be able to produce and stop it from going silent.

This diagram shows how the rest of the connections to the switches are made and shows three preset variable potentiometers which are used.

Alien Switch connections2 sm

Note that I found it easier to connect the 3 presets to the TOP side of the circuit board, rather than the side in the picture, with the components on it.  The Stylophone’s pitch control does face this way, and it’s easy to find space on the tops of the two legs to solder the potentiometers.  You just have to make sure they’re out of the way when you put the back of the Stylophone on again.

Make sure when turning the circuit board over that you identify the correct two legs.

To adjust them, start by setting them to mid-position.  Switch on the part of the circuit connected to each one – e.g. the wide-range pitch control – turn it up to maximum pitch and adjust the preset upwards to the point just before it goes silent.  There’s a small area just before this where the tone starts to degrade, and you could turn the preset down a little so this is never reached in normal use.

The original pitch control is somewhere in mid-position in normal use, but don’t forget this may be working in some settings, and may have to be turned up when adjusting the presets.

Once this has been done once, it won’t need doing again.

9.  LDR (Light-dependent resistor, photoresistor or photocell) and LDR on/off switch.  The LDR is a NORPS-12, which has wide resistance range.  The less light that falls on it, the lower the pitch.  It depends very much on the ambient light how close you need to put your hand to it to achieve useful effects, but in many circumstances I’ve found very close – even to the point of touching it.  This is not a bad thing, as you don’t have to stand away from it to stop it working, and it almost resembles a touch switch in this way.

A handy accessory to have is a small torch, with which you can raise the ambient light level and increase the pitch by shining it on the LDR.  I have an LED-based cycle light – 99p from a supplier in Hong Kong – which is very bright, and also has a number of flashing modes, which produce LFO-type effects.

8.  Variable vibrato.  Connect a 1M Log potentiometer between the two wires you disconnected from the power/vibrato board. This gives a transition between full vibrato and no vibrato at all.  Only two of the connections on the potentiometer are used, and you might want to experiment with which of the end ones you use as the degree of control is different, and I can’t remember which way round I put them.

The Stylophone’s volume control (next to the LDR switch on the right hand side, not pictured) was left in place, and still functions as before.  It has no effect, however, when Feedback is on.  You must do as we did with the original Stylophone, which had no volume control, and put your hand over the speaker!  And watch out when using earphones!

General construction notes

1.  The first thing is that the top and bottom halves of these reissue Stylophones don’t come apart easily, like the old ones did.

The old ones were powered by a 9v battery which was on the inside, so you had to take them apart easily to replace the battery.  The reissue ones take 3 AA batteries in a battery compartment which is accessed from the outside with a cross-point screwdriver, so the top and bottom are superglued together.

The 4 main points where they’re glued are near the corners on the long sides, and there is no alternative but to insert a knife or screwdriver in the gap and prise it open.

2.  The black blob hides the main processor that does all the sound generation.  It seems a little sensitive, so avoid soldering near it for all but the briefest time, and don’t solder with batteries in.  I managed to ruin a couple, almost certainly by doing one of these two things.  In particular, be careful when connecting the drone switch to the keyboard circuit board.

3.  I also painted the base black and superglued a metal alien face to the front.  Neither of these things has in any way improved the sound, except insofar as the effect it has on the mind of the player.

The alien face, by the way, actually comes from Roswell, New Mexico in the USA, site of the original UFO flap in 1947.  How much more authentic can you get!


Some useful pointers came from a well illustrated article by TraceKaiser on the forum; and from circuit-bender Freeform Delusion,


How I started

I’m writing this Blog to document some work I’ve been doing in the field of electronic music-making.

I wasn’t an expert in any of these things before I started – and I’m probably not an expert in any of them now, but I’ve learned a lot as I’ve gone on, and I hope if I can pass it on it’ll be a source of interest and in some small way an inspiration to others who are getting involved in this field

When I began thinking about this project I decided to do it in the following way:

a).  To avoid working with computers (until the very end).

I’d used computers extensively in my music before, from Logic for straightforward composed pieces to a variety of other programs for electronic composition or sound treatment.  I expected to return to using the computer in the end, but with the benefit – hopefully – of new knowledge and new sound devices.

b).  To incorporate where relevant some projects I’d started, and mostly not finished, many years ago.

I’d made some guitar effects with a degree of success that could be described as ‘mixed’ – some of them I use to this day, which work very well and can’t or don’t need to be replaced by anything new; some are still around, not quite working the way they were intended to; some never worked at all!

So I decided not to go back to guitar effects, but to concentrate on sound producing devices.

c).  To explore certain specific ‘movements’ in electronic sound-producing, such as ‘circuit bending’ and ‘Lunetta’ devices, and construct some of the ‘classic’ designs along the way.

d).  To explore alternative methods of music input – isomorphic keyboards, game controllers, and other home made devices.

One of the intentions behind this was to create music in more of an informal and  ‘live’ way than I had done using the computer; another was to explore the variety of music- and noise-producing devices now available – usually cheaply in sales, second-hand shops and on eBay.

I also wanted to pursue my obsession with the Stylophone, an early electronic synthesiser of the late 60’s and early 70’s, but recently reintroduced.

I’ve divided the different parts of the project into the following categories:

1.  Modification

In this first phase I would take existing devices and add new features, or expand existing ones.

My principle in doing this was understanding the circuits (to a certain degree) and making appropriate changes to produce specific effects.

2.  Construction

Phase 2 was to build a number of sound-producing devices from scratch, using circuit diagrams and descriptions from books and magazines (I had a number of these collected over the years, and hand-drawn circuits copied from publications in libraries) and from the internet.

Again, a certain amount of understanding of the principles of the circuits would be necessary.

3.  Circuit Bending

In this phase the idea was to take existing electronic instruments – children’s toys mostly – and make them produce sounds they were never intended to produce, mostly without worrying too much about the circuits that produced these sounds and how they were working, which I felt was more within the spirit of the enterprise.

4.  Freeform designs

The intention then was to extend the knowledge gained in previous phases to create new designs, partly modified, partly constructed, incorporating past ideas I had had, but never put into practice and new ideas discovered through experimentation.

5.  Software/MIDI

This phase was to be mainly computer-based, involving programming, which I had not done before.

As it turned out, I was overtaken by events, and parallel with the Modification and Construction, have got involved in some slightly different areas.  However, I’ll write about each of my projects in order, and put them in the appropriate category.


December 2011

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