Hey!
So i’ve made the super simple oscillator and got it to work.
My question is, where now? Especially, do you guys recommend any literature/resources so I can understand how that thing actually works? My plan other than that, is trying out some other capacitors and transistors.
Thanks!
An atari punk console (APC) is a good step!
I don’t know how much you know about electronics, so it’s hard to recommend literature that would be at the right level for you. But a very basic level explanation of the SSO is as follows: Think of the voltage source as analogous to a water supply; the resistor is like a small diameter pipe that limits the water flow, the potentiometer is like a spigot that regulates the flow, and the capacitor is a bucket. Except you’re putting charge, not water, into the bucket.
The more you turn up the pot, the faster the charge can flow (that is, higher current) and the sooner the capacitor will fill up.
Here is where the analogy falls apart, because there isn’t really a good analog for the transistor. But as the capacitor fills up with charge, the voltage across the capacitor increases. The transistor is connected up backwards from its usual way, and with the base disconnected. In this configuration it initially will not conduct — to force it into the analogy, it’s like a valve connected to the bucket, but the valve is closed. However, once the voltage on the capacitor gets high enough the transistor goes into avalanche breakdown, which means it suddenly starts to conduct. The “valve” opens and the charge starts to drain out of the bucket. As the capacitor empties the voltage on it decreases until at some point it becomes too low to sustain the avalanche in the transistor, so the valve closes and the bucket fills up again. The charge in the capacitor, and therefore the voltage on the capacitor, keeps rising gradually, dropping quickly, and rising gradually again. If you connect that voltage to a speaker the oscillating voltage gives you a tone. By changing the pot you change the rate at which the capacitor charges up, so it fills more slowly or quickly and the tone becomes lower or higher. Using a larger or smaller capacitor will also make the tone lower or higher, because a larger capacitor takes longer to fill.
The LED doesn’t do anything crucial. It lights up to show you the circuit is on. If you use a much larger capacitor it will fill too slowly to make an audible tone, and the LED then will be seen to flash on and off as the voltage rises and falls.
it’s a different design, but you could check out my video series on VCOs here. i try to explain it as laymen-friendly as possible!
Superb video. Saw this a few months ago. Great level of detail. Bravo!
Damn thank you so much for this detailed reply, things do seem clearer now
I’ve already seen it, great vid
I am in the process of building it
Hi there, I thought I would add to this thread, rather than start another one, as I’ve just finished making a few super simple oscillators. Although I’m a complete novice, thankfully I managed to get them to work, apart from when I used an ss9018 transistor with a 9 volt battery, which caused the signal to cut out, the higher up in frequency it went, so I changed the resistors and managed to get to pots to function, although I think that has compromised the overall pitch, so I’m not sure whether I will need lower value capacitors, if that makes sense?
I’ve also added a micro/push button switch to a single oscillator and was wondering if it was possible with multiple oscillators to connect a number of switches with various resistor values that could individually activate the oscillators at a
different voltage/current, so would individually affect the pitch? I’m sorry if this doesn’t make sense, as I’m a complete beginner and starting to get big ideas before I’ve learnt anything!
Maybe with something like that
I’ve made a pseudo mini keyboard (4 notes) with that idea for my Pink Drone Oscillator (it’s a 5 voices super simple osc) but i put it on the master pitch pot and use some trimpot instead of resistors.
That’s great, thanks for your help - - I was wondering if a trim pot would work👍
You could build 2 more with different cap/res values and build an RC filter (its shown on that vid where sam dresses up his oscilloscopes, ill link soon as I find it) that will give you a chord drone with some tonal filtering.
May be you have the bits to make a Vactrol for each SS Oscillator, just for individual Osc control or even the RC filter!
Theres also a simple distortion Sam made on a cereal box (im still meaning to make this)
Theres a bunch of simple bits and bobs to experiment with, Solar panels as a CV source for example =)
(Sorry for the bad formatting and lack of fun hyperlinking. My phone sucks as a computer =P)