UCreate Music, Part 1

This post concerns a very interesting device which was made a few years ago by Radica, a Mattel company.  It was manufactured for a very short time between 2009 and 2010, and supported only until 2011, but examples still appear on eBay, sometimes for very reasonable prices. I got mine for less than £10, which I thought was pretty good for a comparatively sophisticated machine.

The way it works is by playing loops, which you can choose from its memory – one each from 4 banks of 3 loops, in the categories ‘Back Beats’, ‘Riffs’, ‘Licks’ and ‘Runs’ – and apply effects to.  You can also record two of your own samples to add into the mix.

This is how you would normally use it (ignore the toggle switch and sockets on the left-hand side: this and other modifications I made are described later):

There are two reasons why the UCreate captured the imagination of electronic music-makers.  First of all, you could connect it to your home computer via a USB socket on the back and make use of software that would allow you to save recordings of songs, reorganise the loops and effects and download new loops from Mattel’s UCreate website.  I’ll return to this topic later.

The second thing was the range of 8 special effects, and the fact that these are available not only to the loops played back by the UCreate, but also to any audio source connected to the Mic or  Line in sockets.  The effects – referred to as ‘FX and Filters’ – comprise Tremolo, Distortion, Flanger, Phaser and Echo, a variable low-pass filter, and two unique and unusual effects called Forward/Reverse Looper and Rewind Spin Looper.  These work by recording very short samples and replaying them in various ways controlled by the user.

The way the effects are controlled is also highly unusual:  a large Button on the front panel can be pushed and tilted left/right and up/down to vary two parameters of the effect – for example left/right controls the speed of the flanger, up/down controls the depth.  If you find a setting you want to leave for a while, a ‘Hold’ button fixes it where you’ve set it until ‘Hold’ is pressed again.  The fact that the whole Button is lit up when in use  with flashing blue LEDs is just the icing on the cake.

Leaving aside the loop playback feature for the moment, this effectively makes the UCreate an inexpensive, but versatile multi-effects unit, playable in real time.  Although only one of the effects is available at a time, the Forward/Reverse Looper and Rewind Spin Looper in particular, together with the ability to control these in real time with the Big Button, makes the UCreate a useful and unconventional device to have.

I began by using the UCreate in this way, making just a couple of small modifications to it.

First, I added a socket for an external power source; then, as I had done with a number of my other instruments, I added banana sockets for connecting a larger external 8ohm speaker and a DPDT switch to cut out the internal speaker when this is in use.  There is a headphone/external speaker socket on the back of the Ucreate (which also cuts out the internal speaker when a plug is inserted), but this is a 3.5mm stereo socket, as you would find on a PC or mp3 player and is more suitable for use as a Line out.

These are the audio and USB sockets on the back of the device:

Next, imagining a situation when both hands might be occupied in operating the loops and effects and not able to control the volume, I added a socket for an external volume pedal.  This was a 3.5mm stereo socket with internal switches, like the Line out socket.  I used a small size socket purely because of the lack of space inside the case.

On the small circuit board attached to the on/off/volume control, I broke the connection to the centre of the volume potentiometer and rewired it to the socket so that when nothing was plugged into it, it was connected directly to the main Ucreate circuit board, as originally designed; when the volume pedal was plugged in, the potentiometer in the volume pedal was added into the circuit.  This would enable the maximum volume to be set by the original volume control and the pedal to move between this and zero volume.

The pedal itself was simply a cheap second-hand Bespeco volume pedal.  I removed the original sockets and the circuit board inside and connected the potentiometer to a 3.5mm socket, wired in a similar way to the socket inside the Ucreate.  The tip was connected to the input from the Ucreate and the ‘high’ end of the potentiometer in the pedal, the sleeve to Ground and the ‘low’ end of the potentiometer, and the ring to the potentiometer wiper, the centre tag. (I should have built this before, as it would have been useful with many of the instruments I had made or modified, and I’ll have to consider retro-fitting sockets to them so it can be used).

I then decided to take a closer look at the big control Button.  I tried dismantling the mechanism, but couldn’t seem to get it completely apart.  This may have been because it was pressed or glued together after the circuit board was wired in, and I wasn’t going to risk breaking it by trying to prise it apart if it wasn’t meant to do that.

However, I got it apart far enough to see that it used a joystick for the left and right and up down movement.  This was mounted on a small PCB, and on the bottom of the PCB there were three momentary switches, set out in a triangle.  These were like the ones you often get on game controllers: they’re soft and squishy, and when you press them they join two contacts on the PCB; when you take your finger off, they spring back into shape and the connection is broken.

All three switches were connected the same, and later experimentation showed that they had exactly the same function as the ‘Hold’ button, except they were momentary instead of latching.

This gave me two thoughts: first of all, with essentially a joystick and a momentary switch under it, it would be possible to use the UCreate’s Big Button to control another instrument or effect that normally used a joystick or two separate potentiometers; and secondly, there was no reason why the UCreate couldn’t be controlled by two potentiometers or an external joystick.

The way to do this would be to put the Button back and separate the connection between the UCreate’s main PCB and the Button PCB, and then route these connections elsewhere.

The link was made with a 9 way ribbon cable; the names of these 9 connections were printed on the main PCB, and even where this didn’t mean a lot, it was easy to follow the the tracks on the Button PCB and see what their functions were.  So I cut the cable.

From top to bottom, the connections were:

VCC_33 – which connected to one side of all three switches

IOA15 – connected to the other side of the three switches

GND_ADCVCC33 – connected to one end of the two joystick potentiometers (the ‘low’ end, presumably)

LINE 3 – the centre tag of one of the potentiometers (the ‘up/down’ one, which I called ‘Pot 2′)

ADCPVCC33 – the other end (‘high’ end) of both potentiometers

LINE 2 – the centre tag of the other (‘left/right’) potentimeter which I called ‘Pot 1′

R154_1 – one side of one of pair of surface-mounted blue LEDs on the Button PCB

R68_1 – one side of the other LED

V BAT – the other side of both LEDs (+6v, presumably)

Essentially what I did was to connect the end of the ribbon cable that came from the main PCB directly to a DB9 connector on the back on the case.  This was marked ‘In’.  The other end of the ribbon cable, the one from the Button PCB, was connected to another DB9 connector, marked ‘Out’.

In this way, if you wanted to control the UCreate from another device – a larger joystick, perhaps – all you would need to do was connect it to the DB9 ‘In’ socket; if you wanted to control another device with the Big Button, you would connect the other device to the DB9 ‘Out’ socket; and to use the UCreate as normal, just connect the two sockets together with a DB9 cable.

In order to make space for the DB9 sockets, which are quite big, I had to remove part of the bottom half of the case, which stuck up inside:

I think this was probably a carrying handle, but I didn’t think I needed it, so I sawed it off and created a lot more space in the back of the case.

In fact, I didn’t connect the Button directly to the ‘Out’ socket.  Although the Button works brilliantly well for the Reverse and Rewind ‘stuttering’ or ‘scratching’ effects, there was a lack of precision when it came to such things as the filter cut-off frequency, speed and depth of flanging, and so forth.  Apart from anything else, joysticks don’t usually use much of the possible travel of  an ordinary potentiometer, so there was also a restricted range over which the Button was operating.

So I decide to squeeze a couple of potentiometers into the case, which would be selectable in place of the Button.  The two connections for the centre tags of the potentiometers (‘Line 2′ and ‘Line 3′)  coming from the Button PCB went to one side of a DPDT switch, and the poles went to the DB9 ‘Out’ socket.  The wires from the other side of the DPDT switch went to the centre tags of two potentiometers, which I squeezed in the front of the case.  The two connections for the ends of the potentiometers went to the potentiometers and to the socket.

In the event, I also added a 10k preset, set at about halfway, in the circuit at the potentometers’ ‘bottom’ end: it seemed to me that some parameters – e.g. the filter cut-off frequency, and the volume pot when using the tremolo effect – were going too low, at the expense of effects that could be obtained with higher resistance.

The way the UCreate works, the potentiometers  - and the potentiometers under the Button, come to that – have no effect unless one of the ‘Hold’ buttons is pressed, so I needed to add a momentary button, preferably somewhere near the potentiometers.  There was just about room, and what I decided to use was a toggle switch with a centre off position, momentary on in one direction, latching on in the other.  This would enable me to engage the momentary switch, adjust a potentiometer, then when I had exactly the sound I wanted, latch the switch on.  So the two connections for the switch went both to the DB9 socket and to this new switch.

In fact, they went to a third place: a standard (1/4″ or 6.35mm) mono jack socket to which a ‘Hold’ footswitch could be attached.  I used a standard size jack in this instance because I had some nice ready-made footswitches: they’re apparently sold for use with tattoo machines, but come with standard jacks attached, which is very handy.

So that’s how I modified my UCreate, producing a versatile and quite easy to use multi-effects device.  This picture summarises most of the changes I made:

I don’t know if they’re all the same, but the grille on the front of mine came off very easily, so I took the opportunity to remind myself of what the 8 effects are, and what order they come in.

The front and back of the device now look like this:

and here’s what it looks like in operation:

BigBoy BeatBox

You’ve got a Stylophone, you’ve got a Stylophone Beatbox – but don’t you sometimes wish the two could be combined into one instrument? . . .

Well, now that wish has become reality, with the ‘BigBoy BeatBox’: two great Stylophone products in one!

As the picture suggests, the BigBoy BeatBox is, in fact, two great Stylophone products literally glued and bolted together, with some of their internal circuitry combined.  The way it was created was like this:

1.  The Stylophone

The Stylophone half of the instrument is, in fact, a recreation of the original ‘Big Boy’ – a regular Stylophone S1 inside a Beatbox case.  As mentioned in an edit to the original post here, I managed to inflict terminal damage on the ‘Big Boy’ by reckless experimentation.  I normally do this before finishing an instrument, this time I contrived to do it afterwards . . . so the first thing I had to do was remove and replace the electronics with a new donor Stylophone I had lying around.

The actual process closely followed the construction of the original, but was made easier because of the sockets and wiring still remaining in the Beatbox case.  First of all, the end had to be sawn off the Stylophone circuit board, which is too long to fit in a Beatbox case; then the lowest 12 notes of the keyboard were connected to the 12 outside pads of the round Beatbox keyboard.  Fortunately, the wires attached to the Beatbox keyboard remained in the case, and just needed connecting to the appropriate Stylophone keys.  The Beatbox’s amp circuit board was taken out, but the Stylophone’s was kept and connected to the Beatbox’s speaker.  A power socket was connected to the Beatbox’s on/off switch, and the Stylophone’s on/off and vibrato switch circuit board disconnected.

I decided to replace the ‘Big Boy’s troublesome original 3-way octave switch with a simple  pitch potentiometer.  I used a 100k for  coarse tuning, in series with a 10k for fine tuning and a 100k variable preset to fix the highest pitch available.  Previous experimentation with Stylophones had taught me they have no objection to going down to very low pitches, but they cease to function – usually temporarily – if the pitch is taken up too high: on resetting, when this happens – by switching the power off and on – sometimes they will begin to work again, sometimes they won’t.

That’s what I did to the original ‘Big Boy’, and there’s no cure apart from throwing the circuit board away and starting again.  The likelihood of this happening is increased because I don’t just replace the tuning potentiometer pin-for-pin – the range of voltages available between the two pins the Stylophone uses isn’t wide enough for very large pitch variations, so I use only one of the pins that the original tuning potentiometer was connected to – the left-hand one – but connect the other one to +v.

The two new pitch controls were fixed to the front (the rounded end) of the Beatbox case, as was a replacement 10k log volume control.  The problem with the Stylophone’s original volume control was not that it wouldn’t work perfectly well, but that it would have had to be on the side of the case which I was intending to fix permanently to  the other Beatbox.

The original ‘Big Boy’ had no vibrato, but I decided the recreation should have a variable control, as fitted to the ‘Alien’, my first Stylophone modification project.  All this involved was connecting a 1M potentiometer instead of an on/of switch between the two vibrato connections next to the power connection on the main Stylophone circuit board.

Apart from an output socket and a switch to cut out the internal speaker, that half of the BigBoy BeatBox was done.

2.  The Beatbox

The other half of the instrument was a plain beatbox, with very little in the way of modifications.

The first thing I did to it was to replace the tuning potentiometer with a larger one of 100k (a direct pin-for-pin replacement this time), allowing for considerable slowing down and lowering of the pitch of the drums and other sounds.

I also followed an excellent example in this YouTube video: http://www.youtube.com/watch?v=xXdelnxXF7A to add buttons in parallel with the ‘Record’ and ‘Play’ pads normally operated by the stylus.  The trouble with the stylus-operated method is the delay in time between activating ‘Record’ with the stylus, and then using the same stylus to stop recording and begin playing the pattern you want to  be looped, as the loop begins the moment ‘Rec’ is selected.  With a small normally-open tactile switch as an alternative method of beginning and ending the recording period, you can be much more accurate as regards timing.

It’s worth mentioning at this point that, like the original Stylophone itself, the Beatbox comes in more than one variety, as far as circuitry is concerned.  I noticed two significant variations between the Beatbox I used in my ‘test to destruction’ phase, and the one that eventually found its way into the finished instrument: in one case, there was a tap from the battery compartment at 3v, which fed into the circuit (via the 3-way tone control) as well as the full 4.5v; and the layout of the circuit board was different.  As it happens, spots on the board marked ‘Rec’ and ‘Play’ were easily accessed in one case – the test unit – but not in the other – the one I was eventually to use.

In my experience, the Beatbox is a very delicate circuit, and it doesn’t take much to do something to it that will cause Record or Play to malfunction, or the output quality of the sound samples to degrade; so, proceed with caution, I’d say.

A third new button I added to this unit was ‘Reset’.  The Beatbox’s method of erasing an old loop and re-recording a new one is to switch the power off and on again.  The original power switch had to be removed as it was on the side of the case which was going to be fixed to the other Beatbox case – and there would, anyway, be a single power switch for both units: so the third button is a direct replacement for the Beatbox power switch, but now a normally-on, push-to-break, supplying power to the Beatbox side only.  To reset and re-record just takes a quick press and release of this button.

Finally, a new 10k log output volume pot was fixed to the front of the unit.

3  Joining the two halves

Superglue and two bolts was all that was required to physically join the two Beatbox cases, plus a couple of holes through which wires could pass from one side to the other.

The easiest way to connect the power seemed to be to detach the +v and 0v wires from the battery compartment on the Beatbox side and attach these to the original ‘Big Boy’ Stylophone side, which had a power input socket.

In the end I decided that whereas the battery compartment of the Big Boy Stylophone had to be removed – there was no room for batteries as well as the Stylophone circuitry – the one in the Beatbox could be used.  So I wired in a power cable which ran out of the back and was just long enough to reach the power socket in the other half.  In this way the instrument could be powered from an external source, or from internal batteries, and there was no need for a switch to change from one to the other.

The two 10k volume controls were taken to two individual tone controls.  I just wanted something fairly rudimentary, so I used a circuit from http://www.muzique.com/lab/swtc.htm called the ‘Stupidly Wonderful Tone Control’.  The component values I used were quite different – and I have no idea why – but the format of the circuit was more or less the same, and gave a little bit of variation to the tone.

After the tone controls, the two outputs were joined with 10k resistors to the original Beatbox volume control, and then the ‘Big Boy’ Stylophone amp circuit board.  This meant that the sound from both units was going to the ‘Big Boy’ half , and the volume and tone of each unit could be independently varied.  The input to the Beatbox amplifier was disconnected, and the speaker removed.

Now I had an instrument in a single conjoined case, with a single power supply and output through a single speaker or output socket.  There were two styluses and two keyboards, and – as I had hoped, but not expected with any confidence – both styluses work on both keyboards!  This means that both units can be played with a stylus in each hand, and quicker and more rhythmic patterns can be played.  I extended the wires to the styluses slightly to make sure they could reach right across both keyboards.

When using two styluses on the ‘Stylophone’ side of the unit, the ‘Beatbox’ side needs to be set to ‘Play’, otherwise that stylus will only work for a very short period and then not sound any more.  I haven’t timed the ‘very short period’, which might give a clue, but this is probably to do with the circuitry which regulates the maximum of 8 seconds (at ‘normal’ tempo) for which the Beatbox can record.

The complete circuit looks something like this:

The following pictures show the inside of the instrument shortly before it was finished:

This is the ‘Big Boy’ stylophone half.

1 = speaker cutout switch

2 = socket for external 4.5v power source

3 = 3.5mm sound output socket

4 = Stylophone S1 circuit board with permanently soldered connections to first 12 keys

5 = socket for extra stylus, remaining from original ‘Big Boy’ design – not really needed now

6 = fine tune pitch control

7 = variable preset to prevent the Stylophone’s highest note from being too high and causing the circuit to malfunction

8 = coarse pitch control

9 = Stylophone volume control

This the Beatbox half.

1 = the original Beatbox output and ‘mp3′ input sockets, no longer used

2 = Stylophone tone control

3 = Beatbox tone control

4 = Original Beatbox volume control, now master volume

5 = ‘Reset’, push to break switch

6 = wires going to ‘Play’ and ‘Record’ push to make switches mounted on top surface of Beatbox

7 = original Beatbox tempo switch, still in-circuit, but no longer used

8 = Beatbox pitch control

9 = Beatbox volume control

The features visible on the outside were these:

Before finishing I gave the speaker grilles a coat of blackboard paint.  The reason I used blackboard paint was a) it was the only black paint I found in my garage not in a spray can, and 2) it gives a pleasing matt finish, but is more durable than water-based matt emulsion.

The rear of the instrument was sprayed black and the holes masked with painted material.

Bits & Pieces 4

I wasn’t expecting to add this post just yet, but I had a stroke of luck which has enabled me to complete the scheme for my mono mixing section which I started writing about when I described the Red Dragon the other day.

I bought a job lot of small SoundLab mixers off eBay which were said to be faulty returns.  I thought I might be able to salvage some parts from them, use bits of them in some way, or even repair them – but it turned out that several of them appeared to be in working order.

Two of them were straightforward 4 channel mono mixers – an updated version of the one I had used before, I presume – so these were immediately used for the left and right channel inputs to the mono mixer, as I described in the previous post.  Generally speaking, I wanted to have the lower tones to the left and higher tones to the right, so my ‘double bass’ stylophone was the first thing to be plugged into the left mixer; the treble stylophone and the SoftPot Stylophone in the right.

More interestingly, the two other working units were the G105C version with ‘microphone effects’ – a delay circuit which I guessed was probably based on a PT2399.  I opened up one of the dead ones, and found that this was the case.

The circuitry was very different from the original SoundLab mixer I’d acquired – all surface-mount components; everything, pots and sockets included, firmly fixed to a single circuit board – and I’m not sufficiently skilled or equipped to be able to repair something like that.  Not only was it not functioning, it seemed to short out the power when the on switch was pressed.

I sawed out the part of the circuit with the PT2399 on it, which didn’t short the power when used by itself, but didn’t do anything to the input sound either.  This section is permanently in circuit when the mixer is operating, so maybe that was why the original unit didn’t work.  In any event, I decided to put the broken ones away for another day, and concentrate on the ones that worked.  The case would find a use later on.

First of all an echo unit is a really useful thing to have – and 2 echo units with 4 inputs is a bonus!

My initial arrangement with these is to have the outputs connected to the new Left and Right Mixers.  The left echo unit is used for instrument input and the output is divided: one half of the output going directly to the Left Mixer, the other half going to the right echo unit, and from there to the Right Mixer.  As the delay time and feedback (number or length of repeats) are separately adjustable on the two units, some interesting stereo effects are possible.

Bits & Pieces 2

This Bits and Pieces post is about mixers.  There is nothing inherently new or exciting in my system, which isn’t complete yet, but it’s building up to something more interesting in the latter stages.

The part I’ve been working on is the section for mono instruments, which works like this:

First of all I started with a small 4-channel mono in-mono out Soundlab Micromixer for £6 or £7 on eBay.

Fortunately, this came with a circuit diagram, so it was easy to add 4 more identical input channels.  These are housed in the ‘Red Dragon’, a Stylophone case from which the innards had been removed (for use, I think, in The Gemini, which is two Stylophone circuits in one body).

The Red Dragon feeds the Micromixer with 9v power as well as the 4 extra input channels (the ones with red caps).  But I like working in stereo, so the 4 extra inputs are switchable from mono to stereo: the stereo side of the switch sends the input via a passive mixer (a 10k resistor on each channel) into the input of a pseudo-stereo circuit, and from there to a stereo output socket.

I’ve lost the circuit diagram and explanation of the pseudo-stereo circuit, but it was published in an electronics magazine in the 1980′s, and I bought and made up a kit version from them.  It may even have been the work of the amazingly prolific RA Penfold.  At the time I used it to listen to mono cassette tapes on my Walkman, and it improved them no end.  An empty cassette box was just big enough for the circuit board, headphone socket and PP3 battery; it was still in this box when I recently found it, and needed only a replacement 741 op-amp, which had evidently been scavenged at some point in the past.

I don’t remember precisely how it works, but it seems to be some sort of frequency-dependent phase-shifter, whereby some frequencies are sent to the left ear, some to the right, spreading a single mono signal throughout the stereo field: perfect for sounds with a rich harmonic content – like the Stylophone, for example.  (Mono instruments The Alien and The Hedgehog are ideal candidates for this treatment).  Which one of the channels is ‘left’ and which is ‘right’ using this system seemed entirely arbitrary to me, so I added a switch to reverse the output channels, according to taste.

In fact, there was room for two more input channel pots on the top of the Stylophone case, but no room for the switches and circuitry beneath, so these two channels (the ones with blue caps) go directly into the passive mixer and pseudo-stereo.

While the stereo signal currently goes directly to a stereo in-stereo out mixer, the mono output goes to a 6-channel mono in-stereo out mixer (a Realistic 32-1210, £10 off eBay) .  This has a balance control on each channel, so the intention is that the section described here will be the centre channel, and there will be further sub-sections for left and right parts of the stereo field.  Later posts will indicate how this works out.

The stereo in-stereo out mixer (£6 off eBay) is a Hama SM502.  Although the inputs of this mixer are marked ‘Microphone’, ‘Magnetic/Ceramic cartridge’, ‘Phono’ and ‘Tape’ (i.e. it’s a mixer intended for a domestic hi-fi!) experiments have shown that they work fine with the signal levels involved here.

The SoftPot Stylophone

Ever since I found out about the ‘SoftPot’, I wanted to use one to control a stylophone.

A SoftPot, if you’ve never come across one, is a type of slider potentiometer – but not a metal one with a knob, like a fader on a mixer: it’s a wafer-thin piece of flexible plastic, and you operate it by pressing on it with your finger, or an ‘actuator’ – something like a pen will do, but it’s better if it has a rounded end not a pointed one, as that won’t damage the thin plastic. It looks like this:

(This is one which still has its backing sheet.  The SoftPot itself is transparent, and sticky on the back).

The normal SoftPot value is 10k. When I looked at stylophone circuits, I realised that in most cases 10k isn’t going to do much. The pitch pot I added to The Alien – a modern reissue stylophone – was 2.2M, and although that amount of variation in pitch wouldn’t really be necessary, 10k would only represent a few notes.

So I looked at one of the original 1970s stylophones, and saw more possibilities there, so I bought one from eBay with a slightly damaged keyboard.

The definitive guide to the sounds and circuitry of the original stylophone is at http://www.waitingforfriday.com/index.php/Reverse_Engineering_the_Stylophone, but the particular circuit variation of the one I had was not quite the same as the one they had. The circuit of mine was like this:

The values of the resistors are a bit blurry in this scan, but you can see that 10k isn’t going to affect the pitch very much if connected to the resistor ladder on the left – along most of the scale, this would represent only about 2 or 3 semitones.

So I concentrated on the area where there is a tuning pot and a resistor to +v and resistor to ground. The tuning pot, which was 25k, allows the stylophone to be tuned, but doesn’t really cover more than about half an octave – still not enough to play tunes effectively.

At first, I tried varying the 470Ω resistor to +V and the 820Ω resistor to ground, but to little effect: adding a 1k variable resistor to the +V end, in series with the 470Ω, and turning it down a bit did seem to help, but in the end the effect I wanted to achieve – a variation between top and bottom of a couple of octaves – was achieved first of all by reducing the tuning pot value to 10k, the magic number, the same value as the SoftPot.

Secondly, the stylophone version I was working on had a resistor in parallel with the tuning pot – a very small one of about 270Ω. Replacing this with a resistance of 1k seemed to do the trick – and in fact I added a 1k potentiometer, as this would function as a narrow-to-wide control of the note range, in tandem with the 10k tuning pot.

A 3.5mm stereo switched socket on the side of the stylophone would allow the stylophone to function normally, when required, but anything plugged into the socket would replace the tuning potentiometer in the circuit. This is how the SoftPot would be attached.

That part of the circuit now looked like this:

and the SoftPot Stylophone looked like this:

The next thing was to make a unit for the SoftPot which could be plugged in when required. This was quite a minimalist design, and was put together like this:

The SoftPot, as previously mentioned, is sticky on the back, so was stuck to a piece of 2mm acrylic sheet cut to fit on top of the keyboard, just clear of the power and vibrato switches, and nestling inside the lip on the right hand side. Underneath this was stuck a smaller piece of 2mm acrylic which fitted inside the keyboard cut-out, and stopped the whole thing from moving as it was played.  These three layers were stuck together, but weren’t stuck down to the keyboard.

The soft pot terminals came attached to a 3 pin socket, the same size as the ones you get for PCB headers. I had some of these, so made up a lead with a 3.5mm stereo plug on one end, and a 3-pin PCB header plug on the other.

You may be able to see from the back of the attachment how it was put together to fit firmly into the keyboard recess:

The SoftPot assembly fitted in place, and was ready to go. All it needed was an actuator – like a pen, but with a rounded end. And, of course, the stylophone has one of these already: the stylus which gives it its name! So the SoftPot Stylophone can still be played with the stylus in the traditional manner, but moving up and down the SoftPot, like a ribbon controller.

There was just one more change to make to the circuit before this could happen. The Stylophone sounds when the +V in the stylus contacts a key, which is in turn connected somewhere within the resistor ladder. Now that the keys had been covered up, there would be no sound without a connection between the resistor ladder and +V – the stylus only pushes the SoftPot together, and the connection is made internally.

As with The Alien and The Hedgehog, I simply made an internal connection between +V and one of the resistors in the ladder – the highest note – operated by closing a switch. Try as I might, I couldn’t arrive at a situation where the SoftPot Stylophone was silent until the Softpot was activated, but still gave a good note range.  So I added a volume control – a feature which any stylophone would benefit from – and when you play, you can turn the volume down when not sounding a note with the SoftPot.

Before finishing up, I added a socket to allow the SoftPot Stylophone to be operated from an external power source, a switch to cut out the internal speaker (this is not done automatically when the lineout socket is used), and a switch to cut out the low-pass filter in the line-out circuit.

These original stylophones are famous for having a simple resistor-capacitor tone control on the line-out circuit which is not in the circuit to the internal speaker. This is the main reason why stylophones sound so different when the line-out socket is used. When you see pop musicians who use the stylophone at live gigs holding their instrument up to the vocal mic as they play, this is not mere theatricality: it is theatricality, of course, but it’s also the only way to get an unmodified stylophone to sound the same to a stadium or festival audience as it does to you when you play it ‘unplugged’ at home.

The other end of the circuit now looked like this:

Finally, I made a small modification for the benefit of a future project which I haven’t yet started on. I added another 3.5mm stereo socket configured in a similar way to the SoftPot input socket. In normal or SoftPot operation the resistor ladder is connected into the circuit; but anything plugged into this socket replaces the resistor ladder.

Stylophones

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.

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.

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.

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 http://wp.me/p25FoK-10). 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 http://en.wikipedia.org/wiki/Stylophone, and see pictures of them on Stylophonica, ‘the official home of the Stylophone’ at www.stylophonica.com. You can also learn more of the history of the Stylophone at www.stylophone.ws (or www.stylophone.fsnet.co.uk), the Stylophone Collectors Information Site; buy a vintage Stylophone at www.stylophone.com, the Stylophone Sales Center; or even make your own Stylophone at www.instructables.com/id/A-Stylophone!

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.

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 www.dubreq.com 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 www.youtube.com/watch?v=BuomrJNd0cM, 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.

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.

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 www.youtube.com/watch?v=xNKFJZX4Na4, uploaded by meltdownband.

Sounds

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.

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].

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.

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.

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:

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.

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:

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

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:

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 www.jameco.com/Jameco/PressRoom/punk.html?CID=punk, the ‘Blast Fed Disaster’ from www.thesquarewaveparade.com, and the article at www.getlofi.com/?page_id=1395, 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’.

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.

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.

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:

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.

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:

A:
B:
C:
D:
E: 

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:

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.

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!

Acknowledgements

Some useful pointers came from a well illustrated article by TraceKaiser on the www.stylophonica.com forum; and from circuit-bender Freeform Delusion, www.facebook.com/pages/freeform-delusion/144587583120.

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.