Posted: Thu Nov 15, 2012 6:15 am Post subject:
Starved 40106 phased oscillator
I don't know if anyone out there has a circuit modeller, but I'd love to see what it makes of this.
It's a triggered osc/env which runs off any CMOS output. The caps will determine how long it hangs, but beware that all the bypass caps will affect the env cycle, especially if running on battery power, (9V)
Phase separation between the A-F points is 50% or more at some frequencies.
I can get some pretty cool waveforms out of it, just as it is.
But I'd be very thankful for any ideas you guys have about it.
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_________________ What makes a space ours, is what we put there, and what we do there.
I've got a bit of space left on the board, which is for the second 40106, and I'm seriously thinking of building this version of the oscillators, hard wired into that space, and leaving the first one as my experimenting area.
To add an extra challenge, I'm gonna replicate this circuit around a little audio transformer. The transformer windings, taking the place of the two inductors. I'm not exactly sure of what this will achieve, but I s'pose that's part of the fun. I am 99% sure it will oscillate, but not sure at all about how it will oscillate!
There could even be some old diodes in the wings, just itchin fer som aktion! _________________ What makes a space ours, is what we put there, and what we do there.
Posted: Fri Nov 23, 2012 9:01 am Post subject:
Experiments So Far...
Hi,
I've been trying out your oscillators on my PC scope, but I'm not sure if I've discovered anything too exciting yet! I've been using two 40106 oscillators to work the trigger and accent, but they are not synchronised.
The problem is that, although the waveforms pre-4070 look like they are being filtered somewhat, the output post-4070 has been squared-up again. There may be subtle phase-shifts going on, but I haven't yet spotted any radical signs of it. I've tried changing L1 and L2 to 68mH and 10mH respectively (about 3 orders of magnitude higher) and it does affect the outputs at pins 10 and 8 of the 40106, but the output at pin 3 of the 4070 doesn't look substantially different. I've recorded a bit of each for you to listen to, to see if you can spot the difference. I will try some variable inductors next, as it may be more easy to spot the difference as you alter the inductance.
Anyway, that's all I've done for now.
Gary
Nexus 1 Oscillator (as per schematic).mp3
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Nexus 1 Oscillator (higher value inductors).mp3
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Wow,
Thanks heaps for doing those scope shots Gary.
I would have thought that all those holes in the 4070 trace show that there is alot of phase cancellation going on. Remember, I don't want these inductors to "filter" the output. Simply to create more delay, and hopefully add more strange artifacts, especially when the other half of the 40106 is setup as the second oscillator. The phase delay will be more obvious when the tune is adjusted, I hope.
Everything will go through the WSG filter after this.
I've come up with a schem for the transformer idea, I'll post it soon. _________________ What makes a space ours, is what we put there, and what we do there.
I've had to deal with the real world for the last few days (always gets in the way, doesn't it? ). Been thinking that it might be interesting to look at the waveforms as you work along the 40106 chains, to see if there's any interesting phase changes occurring as you go . Today, I've been doing some rough measurements on my variable inductors, to see what sort of ranges I've got. I just wondered what would happen if you replace one or more of the fixed inductors with variable ones and look/listen to what happens as you twiddle them a bit. It might be interesting...
I'll have a go at that tomorrow (actually, later today as it's nearly 2am here) and I'll post anything interesting (if I find anything interesting that is).
Been thinking that it might be interesting to look at the waveforms as you work along the 40106 chains, to see if there's any interesting phase changes occurring as you go . Gary
Yes!!
That's the whole idea!
That's why we take the XOR inputs from the different points along the chain/s, A-F. They are all out of phase with each other in different ways. And when you tweak the tuning, you are automatically changing the phase relationships as well.
With one of the stages inducing a sync type effect through the transformer, it would add yet another level of complexity.
Here's what I'm thinking of building permanently onto the other space left on the board.
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_________________ What makes a space ours, is what we put there, and what we do there.
BTW,
that schem is totally untested at this point. There is a good chance that it will actually howl! But that could be good! Couldn't it? _________________ What makes a space ours, is what we put there, and what we do there.
I just thought!
It's a predominantly percussive instrument, so why not just take two points off each oscillator (in one 40106) and take them straight through a ring modulator? A "real" ring modulator made with two transformers and an assortment of old diodes for the bridge, like that design that,.... hmmm,... oh man, I forget his name. Is it Eric someone?............
Anyway, you get the idea.
With the oscillators close to in tune, you'd still get very nice rich tones, if you want them, but get them a little bit "out", and you'd get a much bigger, clanging kind of beat. High frequencies, way out of tune would be bordering on noise, great for crashes. _________________ What makes a space ours, is what we put there, and what we do there.
Eric Archer, maybe? I know Ken Stone's got one on CGS.
The ring modulator idea seems like a good one. Haven't actually tried a true RM yet. Have you got a lot of old Ge diodes? I believe they work the best (and they should be matched). I've got a few unused ones plus a larger number of ones that I've retrieved from transistor radios etc in the past. I've also got some audio transformers from the same sources. You certainly do get good clanging sounds with an RM.
Sorry, I was a bit slow on the uptake about the phase shifting idea - probably was worrying about the real world again.
Sorry, I was a bit slow on the uptake about the phase shifting idea - probably was worrying about the real world again.
Yeah, happens to me all the time!
I've got lots of modern Ge diodes, which would be the best chance of matching. I've also got lots of older Ge, including some of the dinosaurs in glass painted black. The OC71 is a classic, got a few of them. Could be fun. Some of those old diodes are like a cats whisker suspended in glass. Very cool.
And yes, it was the Ken Stone PCB I was thinking of.
Ken Stone -> Eric Something
Kinda almost nearly the same! _________________ What makes a space ours, is what we put there, and what we do there.
Posted: Tue Nov 27, 2012 8:39 am Post subject:
Phase changes along inverter chains
Just captured this set of scope traces along the chains of inverters (pin numbers refer to the 40106, obviously). There are definitely phase shifts going on, so these should lead to phase cancelling at the XOR stages. I'm trying to remember how phase-shifts go. My recollection is that capacitors advance the phase and inductors cause phase lags (is that right?). Combinations of the two then give net advance/lag according to the values. I'm really rusty on this.
Going back to the Ge diodes - yes, I've got some of the point-contact type. So much more aesthetically pleasing than a 1N4148! Must try the Ken Stone circuit one day...
Cheers,
Gary
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I've been tossing around a few ideas about this, but I've realised that the best course of action right now would be to build the permanent copy of the original schem, minus the inductors. I'll add some insertion links where I can on the stripboard, but it really will be a tight squeeze just to do that. The transformer/ring mod mod will have to be a little tower which could be played around with later.
The other reason is that I still haven't heard the two, three stage oscillators, going into the XOR. Which is actually supposed to create a pseudo ring-mod sound anyway. (once we have two inputs with different frequencies, rather than just different phases, the sound will be somewhere else! Hopefully. )
Not to say that playing with the phase cancellation of the XOR across one oscillator isn't cool, cos it really is!
And the last reason is that I've got itchy soldering fingers! _________________ What makes a space ours, is what we put there, and what we do there.
Sounds quite sensible to me, but the phase shifting idea is interesting. I may look at again sometime.
I've got things to do myself e.g. committing a breadboarded mixer circuit to PCB/perfboard. Sometimes, I'm more in the mood for experimenting on breadboard, but when I fill up all available breadboard space, I feel I should be doing something more permanent!
Joined: Nov 10, 2011 Posts: 878 Location: Lancashire, England
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Posted: Thu Nov 29, 2012 2:38 am Post subject:
This looks a lot like something I was working on while my internet was down, I'll make a separate thread for my version as it relies on different circuitry but does similar things- phase shifting etc
I'd suggest trying to use your circuitry with analogue waves and op amp buffers/inverting amplifiers for some really nice results (just omit those gates on the end, perhaps even replacing them with diodes to make an analogue OR gate?) anyways just some ideas, this circuit looks like it will certainly have some good effects! Carry on the good work _________________ As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"
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I am 99% sure it will oscillate, but not sure at all about how it will oscillate! 
). Been thinking that it might be interesting to look at the waveforms as you work along the 40106 chains, to see if there's any interesting phase changes occurring as you go 
. Today, I've been doing some rough measurements on my variable inductors, to see what sort of ranges I've got. I just wondered what would happen if you replace one or more of the fixed inductors with variable ones and look/listen to what happens as you twiddle them a bit. It might be interesting... 
But that could be good! 
