maybe i don’t know for 1 hundred one, but just for this build (4osc) he explains that he uses 100k to connect them together like in the simple schematic
unless @RaphaelLari want to build 100 osc … 
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Let’s ping @lookmumnocomputer – hey Sam, can you update the super simple oscillator schematics to clearly mark out the emitter and collector, since that keeps confusing builders who are trying to match by eye, and the circuit most likely won’t work if you get it wrong.
(for extra bonus, add a + to the electrolytic too while you’re at it, since people aren’t very consistent with what that symbol means on its own)
For more on this, see this thread and all the threads that link to it 
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btw do you guys know if Sam posted some stripboard layouts of the new modules somewhere? i know that some are kinda the same of the old ones…
That’s a cool little VCO circuit and you can explore it further in the falstad circuit simulator as one of their examples.
Unfortunately its voltage to frequency relationship is linear, not 1V/octave which make integrating it with a Kosmo, Eurorack or Moog synthesizer a bit difficult. (You need to add a exponential converter, I was actually playing with that yesterday and came up with this circuit this circuit, but the triangle wave was no longer symmetrical because of imperfect current mirrors and I gave up. If someone sees a quick fix for it, I’d be curious to hear about it.)
It probably works with a TL074 too.
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I linked to Mitch’s Robin’s own exponential converter above
Depends on how you power it; I don’t think it’ll work with single supply, given the TL07x series limited common mode voltage range (get too close to VCC– and it messes up).
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2 years on later… yes I should probably do something about this! right ill get looking at it. ill re draw this drawing tomorrow morning. with a bit more information. thanks fredrik for the nudge!
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Yeah, sorry, you should have thought of this before you set up this forum 
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I did a little digging beforehand and it seemed that the 324 was better suited than the 74.
The basis of the circuit, or at least one reference, can be found in one of the very few Text Books I have ever owned “Horowitz and Hill”… I used this at school. Page 134 references the same circuit using the 3160…
Rob
You are both right, for single supply, the TL074 wouldn’t work.
We were talking of a bit of a re-design (replacing two chips by one) presumably targetting the Kosmo format and ±12V power supply, that’s why I figured the TL074 could probably be used.
You reminded me that I also have that book, I bought it way back in 1987, apparently for $46.25.
That seems quite expensive for the time, I didn’t know I had that kind of money then for what was just a hobby related book.
I’ll have to go back and read the section on current mirrors, to figure out how to improve the design I linked to above.
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