I’ve been musing about guitar pedals for a while now; several past attempts at a tremolo have been instrumental learning experiences for me. As it happens, the knowledge I have now about transistors gives me hope for a new, cleaner tremolo pedal down the line. Harmonic tremolo was always an interest too, as when I was first designing my tremolo pedal a couple of years ago there wasn’t really any popular version in the pedal market. Since then, JHS have come out with an affordable tremolo pedal with a switch to alter it to a harmonic mode – so much for me taking the market by storm.

I think the next thing that I would like to try and manufacture is a dual wavefolding circuit, with impedances set up so that it can function with a guitar. The lockhart wavefolder below seems like a great place to start and I have pretty much all the parts barring that NPN transistor. I think that a wavefolder pedal with modulation options would be fantasticly psychedelic, and the notion of gigging with my own pedal designs is very alluring.

These scans document and lay bare the design process for my synthesiser. Some of these scans really belong in blog posts further down, but I thought that I would include them all in one post for the sake of being concise, and also so that none end up being left out.

Hinges attach the front panel of my synth to the case; a purposeful design decision both from a construction standpoint but also to inform the user experience. Too many of the devices that we encounter in daily life are black boxes, in that we have an understanding of the inputs and the outputs but not of the processes through which these inputs are transmuted to the outputs. The term black box is a recognised phrase within the field of system analysis, often utilised within computing. It is a method of studying a system without delving into the innerworkings, noting only the causality between stimuli and response. From phones to transistors or diodes, this is a manner of describing a great many technological systems that are regularly encountered; my understanding of electronics, for example, is heavily reliant on certain black boxes. I do not fully understand exactly how an opamp works internally, but have a strong enough grasp on how it takes inputs and what appears at the outputs. This is entirely enough knowledge for me to use them well, and to create larger systems such as synthesisers. This phrase can refer to more abstract systems too:

“The child who tries to open a door has to manipulate the handle (the input) so as to produce the desired movement at the latch (the output); and he has to learn how to control the one by the other without being able to see the internal mechanism that links them. In our daily lives we are confronted at every turn with systems whose internal mechanisms are not fully open to inspection, and which must be treated by the methods appropriate to the Black Box.”

W. Ross Ashby, ‘An Introduction to Cybernetics’

Whilst black boxes are both useful and necessary in todays world of hyper-specialisation, I seek to make visible that which others in my field would readily hide. I would like to encourage curiosity, a pedagogical approach to electronics in which the user feels like the innerworkings are not locked away behind 12 tiny screws, but instead laid bare infront of them. Rewarding curiosity, encouraging repair and modification, these things are essential to creating the type of investigative mindset that I aspire to foster in my creations.

This synthesiser project has prompted me to learn about the innerworkings of transistors; they are fascinating devices, and underpin my learning about opamps. I feel as though I am encroaching on the base elements of electronics: the BJT transistors that I have bought and have been researching are constructed of a sandwitch of silicon, either PNP or NPN. The P or the N refer to silicon that has been ‘doped’ with other elements that with will result in it having more free electrons (P) or less (N). Silicon is a semiconductor; this means that it can conduct electricity under specific conditions. For example, if silicon is heated to glow red hot, it will conduct electricity. The NPN or PNP transistor relies on a concept of electrons and holes, which is still sliiightly out of my grasp, but the notion that I am dealing with elements (perhaps alloys, if they are doped?) rather than contrived, human-made devices is immensely exciting! The sheer simplicity of the devices that I am manipulating is encouraging to me: I feel as though I am dealing with very natural forces, not operating within systems that have been constructed for my benifit. The idea of learning a coding language, for example, is at complete odds with this thought process: the things learnt within that language might be entirely obsolete within the next 30 years, but silicon will not be obsolete so long as we have electricity. This is a seemingly illogical thought process, but is rooted in themes of DIY culture and (once again) in the childlike delight in asking ‘why??’ time and time again.

BJT transistors function as a VCA, with only a few additional components. This has been a hugely impactful discovery withim my electronics journey and has opened up a vast world ahead of me. The scan of my notebook below details the breaking-down of a very simple transistor based VCA circuit, and I am already invisioning the voltage control that I can exert over existing circuits that are on my breadboard as I write. All of the writings and drawings below were scribed whilst working at my breadboard; making changes to the circuit, writing down the effects, changing only one thing at a time so as to respect the scientific method which will enable the most efficient gathering of knowledge. I really do feel as though a new world has opened up infront of me.

During the making of the presentation for this unit I came up with the phrase (as a presentation title) ‘at the junction between science and art’ which aimed to sum up my practise as an amateur electronics engineer who is aiming to make interesting and stimulating electronic instruments. This seemed to be quite representative, quite apt, in that my creations are neither wholly in the camp of science (my engineering is amateur and scrapped together from disparate knowledge bases, entirely un-elegant in execution; besides, my goal is not to create an engineering marvel, but rather to create an interesting and artful instrument that is as complex as it is peculiar) nor wholly in the world of art (I spend a great deal of my time crunching numbers and trialling different topologies, measuring and metering, recording my results in a scientific manner – not very artistic, really).

In an effort to reference my work to related practitioners who lie/have lain on a similar boundary, I referenced some of the creations from the book “Instruments and the Imagination” (which has been introduced in a previous post) to illustrate that there are many notable examples of instruments that are both scientific curios and yet also devices of tangible artistic beauty. The foremost notable example is the Aeolian Harp, which is detailed in a prior post, but also as equally notable are the Chladni Figures demonstrated by Ernst Florens Friedrich Chladni, a German physicist and musician. These figures (pictured below) are achieved by exciting a metal plate with a bow, upon which a thin layer of fine sand is laid. The sand arranges itself in different patterns according to different frequencies that the plate is excited to; the sand lies at the boundary of two opposing vibrational forces: nodes, as labelled by Chladni.

His research is heavily involved with the science of acoustics; these discoveries are related to the study of ‘room modes’ that is a common acoustic consideration when designing acoustically treated rooms for studios in the present day, it is also strongly related to the study of harmonics and the harmonic series, along with instrument design (the image below shows Chladni figures for the backplate of an acoustic guitar).

However, these slides present a beautiful picture of art in their own right. Scientists of previous ages would ascribe these to be an aspect of ‘natural magic,’ demonstrating the inherent beauty of the world; today, these are known to be related to the solutions of the Schrödinger equation for one-electron atoms. I seek to find a middle ground between these two perspectives. These patterns, if presented as art generated by a human, would be perfectly viable for a gallery show or exhibition, and yet they are patterns inherent to the physical world that we exist within. Perhaps there is more to ‘natural magic’ than we give credit to; beauty can be found in the manipulation of inherent natural forces for artistic means, and that is exactly what I hope to express with my own creations.

“Any sufficiently advanced technology is indistinguishable from magic”. Said by Arthur C. Clarke in his 1962 book “Profiles of the Future: An Inquiry into the Limits of the Possible”, it is an oft-repeated phrase that requires very little explanation. For our society to become as technically advanced as it currently is, delegation of knowledge is essential and the result of this individual specialisation is that many of the principles that we rely on every day are simply taken for granted. The title of this blog post is perhaps misleading; a more accurate description would be that science is the new alchemy/magic. Cars, planes, electronics, communication, bridges, central heating, digital computing, many of these are simply accepted to work via some logical path that has been worked out by someone or a group of people, but bothering to understand it is both unnecessary and uninteresting to the some of the general public.

Lacking knowledge about the systems that are in place around me makes me feel uncomfortable; blind trust in things that I rely on makes me feel foolish. I understand that the individual specialisation mentioned above is essential to modern living, but electronics is a means for me to get to grips with the systems that I encounter in my practise. Learning electronics appeals to the childlike desire to ask ‘why,’ over and over again. The skill ceiling is incredibly high, which I find comforting, though I doubt that I’ll delve deep into the maths side of things; I’m very happy to have a grasp of simple ratios and the functional workings of components and systems, but advanced transfer functions and other such technicalities seems far over my abilities and best left to the engineers and physicists. Besides, by not understanding the exact manner in which things function (down to molecular level, laid out clearly with formulae) I am able to retain some of that magical, mystical essence that keeps me coming back to the workbench. There is a sense of turning base metals into gold, where the base metals are components and the gold is some homebrewed device that I have dreamt up. This romantic appeal is something that I lean on a lot, which is perhaps why I am drawn to more hardware-centric analogue devices rather than their digital screen-based counterparts. Working with my hands and being able to see the objects that I am manipulating is half of the fun for me.

I’ve just cracked the solution to a problem that has been sitting in the back of my mind for the past few weeks. The problem is as follows: I want to make my current oscillator design (which can provide square and triangle wave outputs) variable in its pulse width. The method that I came up with would also allow me to skew the triangle wave output to give me a variable triangle/saw wave knob, skewing to ramp up and ramp down varieties. This is a setting I have seen on plenty of synths, and I felt that it wasn’t impossible to do by some slight tweaks to my design.

About 1.5 weeks ago I was on a night out, and upon arriving home I drunkenly ordered some diodes and banana jacks+sockets which I thought would be the solution to my woes. The banana connectors weren’t related to this issue, but were born out of a desire to make my synth designs more modular. The diodes, though, I reckoned were exactly what I needed to solve my oscillator issues! The image below was ripped from a website online, and illustrates an opamp based relaxation oscillator.

The capacitor charges and discharges via R (one can safely assume that no current flows through the opamp terminals, as they appear at very high impedance), R1 and R2 set the voltage boundaries that the capacitor charges/discharges according to, by combining ground and the output signal in a certain ratio (described by their relative values). A square wave can be found at the output of the opamp (labelled V⁰), and a triangle wave can be found (at a much lower voltage) from the inverting input of the opamp (labelled V^C). This triangle wave is then amplified, and the two waves are then sent to a 1P2T switch: single pole, double throw. This is just an A/B switch, with the triangle represented when the switch is flicked in one way, and the square when it is flicked the other way.

Googling didn’t really give me any solid answers about solutions to my PWM issue, but I thought that I could use diodes between R and C to affect the charge and discharge time of C independantly. I thought I might run into differences of frequency, but also presumed that if I kept the total resistance of the two resistors the same as R was, then the frequency wouldnt change, just the duty cycle. My assumptions were correct; wiring up two diodes in parallel (facing opposite directions) and then swapping R for two pots of the same value meant that I could achieve the PWM and tri/saw skew without affecting total frequency if the pots were turned together but inversely at the same rate. That means, all I need is a dual gang pot with each pot wired inversely to achieve smooth alteration of pulse width and tri/saw skew !!! This was a breakthrough. The only issue is: R in my previous circuit design was where I altered the frequency, but now I can’t use that point to alter the frequency as the charge and discharge rates are affecting the skew. Further testing needs to be done to see whether a pot in place of R1 or R2 will affect the frequency but leave the amplitude unchanged. If that is indeed the case, then life is bliss and everything is going swimmingly.

Extrapolating into the future, I’m curious where I’ll take all of the knowledge that I’m gaining during 3rd year. I’m interested in making circuits for other people, and I already have some commissions from interested individuals: a harmonic tremolo pedal, fuzz pedal and a dub siren. These will indeed earn me some money but I doubt I’ll reach a point of financial security from them for a long time, they are more akin to passion projects that I can earn from nontheless.

There is also the aspect of repair; repair is a whole other discipline to hashing janky circuits. It requires a true engineers mindset; the sheer lust for problem solving and the ceaseless vigilance to get to the bottom of issues lies at the heart of repairing electronics, and I feel like I have a certain dollop of that already. The knowledge and know-how is another matter, but I don’t doubt that I’ll eventually get there with a bit of practise. I’ve blown up a mates amp head (for the second time, as it arrived on my bench already blown up) in the process of fixing it, and have a number of tape decks that need some sort of repair or calibration. These will be my practise pieces, and I hope to really refine my knowledge through them. If I can get good at repair, then that is a more solid and reliable source of income than making idiosyncratic and peculiar circuits for creatives.

I already do guitar setups for a lot of friends, and have repaired an old digital pedal (removing the IC and then cleaning the contacts was the only issue), and ocasionally have people coming to me with broken thingss as I seem to be the only person in my small bubble of friends with any electronics know-how.

Perhaps one of my final projects will be repair-centered?

I’ve recently had a first rehearsal for a band that will be comprised of me and two other members, focused around homemade electronics and aiming towards folk sensibilities. Our aim (although the vision of the band is still in an ever shifting series of conceptual eddies and swirls) is to take the existing cultures around folk music and then extrapolate them into a context where electronic instruments are as plentiful and well understood as acoustic instruments. The idea being that we will be attempting to make folk-style instruments out of electronics, keeping the DIY ethos that seems important to the folk genre, and then performing folk or folk-style tunes with a combination of these homemade electronic instruments alongside acoustic instruments.

I have very little direct connection to the genre of folk music, so I’m trying to do as much research as possible to inform my decisions about where to take the instruments and the music for this project. I’m very interested in the Broadside Hacks album “Songs Without Authors Vol. 1”, as I saw them last year in the summer and they had a profound effect on me. The concept behind that particular record was “trying to find those untouched songs”, according to Campbell Baum, one of the people who began the band (from this interview: https://tradfolk.co/music/music-interviews/broadside-hacks/). I enjoy this idea of resurrecting songs that are on the verge of death, especially because folk music seems rife with songs that are repeated again and again as some sort of pedagogical practise. It814200 feels profound for them to be reintroducing songs into the canon that would otherwise slowly become lost to the mists of time.

I’ve been reading lots, as well. Trying to find links between folk and DIY culture, but I’m beginning to feel like reading about folk music to try and understand it better, especially from academics, is a tad pointless; ‘dancing about architecture,’ and all that jazz. I think experiencing and listening to folk seems to be the best way to approach it, and perhaps I will realise that there is less DIY in folk that I assumed from my naive standpoint. Nonetheless, I still have some very strong notions of how I want some of my electronic instruments to behave and work.

I am envisioning an electronic chord machine, lets say 4 chords, 3 voices. Each chord is activated by one of four buttons, and each voice in each respective chord can be tuned with pots to achieve the desired chords. There are slew control knobs, however, for each oscillator, resulting in the changing of chords creating momentary dissonance as each oscillator slews to the next note at a different rate. This is not a particularly original idea, regarding the slew; it is utilised in the Dewanotron Hymnotron to great effect. However, I aspire to implement a hurdy-gurdy style crank arm, controlling the gain into a wavefolder. As the crank turns around, the gain cycles in a sinusoidal manner, varying the amount of wavefolding that is occuring.

This hypothetical instrument (drawings to come in a later blog post) is designed to combine the electrical method of playing (buttons, knobs, etc) with the more acoustic method of playing (the hurdy-gurdy-esque crank arm) to produce an instrument that (hopefully) feels somewhere between the two. Made entirely of wood, I think that it will fit nicely in with my ideas regarding exactly how I want my instruments to behave, look, and perform (as noted in previous blog posts).

There are plenty more fascinating historically scientific instruments other than the Aeolian Harp which capture my attention. The maccabre element of some of these inventions really captures my imagination. Consider the Ear Phonautograph, invented by A.G. Bell and C.J. Blake, a device which imparted Bell with the scientific knowledge required to eventually construct the telephone. It is macabre in its utilitarian scientific design that puts the quest for knowledge above all else, using a human inner ear to record vibrations onto a smoked pane of glass. This is a purely visual reproduction of the sound as there is no possible method of playback, but the knowledge that such a light and thin membrane could vibrate such (relatively more) heavy bones such as are in the inner ear, made Bell muse upon the possibility of vibrating magnets with some sort of thin diaphragm, which was what gave the idea for the telephone.

Whilst this particular instrument is not one of sound-making, I admire the grit and determination that it takes to manufacture such a boutique item, and I adore the scrapped-together scientific brilliance of it. It was not made in a lab out of purpose built parts, but more likely cobbled together from bits and pieces of other devices. In an article by Tom Everett for the Science Museum Group Journal (http://journal.sciencemuseum.ac.uk/browse/issue-12/writing-sound-with-a-human-ear/), he notes that despite a lack of documentation relating to the design of the insrument it appears that the base was a repurposed microphone stand, and the diagrams suggest that the inner ear might have been connected purely by a tack affixed through its flesh.

I aspire for my creations to have the same archaic mystique and beauty that is exhibited by this device, both visually and functionally. My synthesiser that is on the bench at the moment is a bespoke design both in housing and in its guts, but I feel that my devices are still in their infancy and I want more crazed mad-scientist charm in my instruments. I want my instruments to encourage play and curiosity, but make the learning process as puzzling and maze-like as possible. I want my instruments to continue to cause joy over time through their idiosyncratic peculiarities, and reward those who desire to dig into their complexities. I feel that this can only really be achieved with patch points of some sort; I bought some banana sockets and jacks very recently so as to realise my goals. Light interactivity or proximity interactivity, are also things to investigate. Proximity being the harder of the two to impliment, I reckon I’ll just start with some simple front panel mounted LDRs to modulate CV signals.