Hello again,
Sorry for starting 2 threads in a row, I just thought it would keep things cleaner.
I built a module with 2 system100m LFOs, using this stripboard layout:
The schematic is here:
Now the square output gives me a healthy 10V bipolar oscillation, but the triangle on both builds only goes up to 4V. Is there a reason for that? can it be fixed?
Thanks for your help!
Jules
Im pretty sure that the triangle is supposed to be lower as the amplitude of the wave is half that of the square and I see nothing on the schematic to amplify it.
Not an expert bit we all moan the triangle is quieter.
the amplitude of the wave is half that of the square
Ah the makes absolute sense! Thanks.
Yeah it’s silly, the triangle is what I wanted most.
I can still use it but it has less potential (pun intended 
I realised I have all the parts handy to build Sam’s 1171 O.B.A so I ordered the boards to be one LFO’s companion. This is growing fast…
Just keep having fun and asking questions. There are no silly questions here. Just folk who are all in the same boat.
Read up on the many uses of the op-amp there are many ways you could modify the circuit to amplify the triangle output. Enjoy.
Never built this but I’ve looked at a simulation and indeed the triangle amplitude is much lower than the square. By the way, this circuit has no discernible resemblance to the actual Roland 100M LFO.
For a couple of similarly simple LFOs that may give a better triangle see:
(Never built those either but they look reasonable.)
Thanks guys,
Yes it’s strange this was called a system100 lfo…
I have found 2 stripboard layouts using the same schematic, both called system100
I guess that’s how you start legends on the web!
Thanks also for the other lfo designs, I’ll save them for future builds.
This whole stripboard thing takes me back to my teenage years building stompboxes, love it!
Oh… Just noticed this remark on the Kassutronics page:
The triangle and sine wave have about 5 V amplitude, the square wave goes full swing of the opamp, about 10.5 V.
The Haillant one has an output gain stage with a variable gain so you can crank it up to ±10 V. Of course nothing stops you from doing the same with the Kassutronics or the “100M”.
Absolutely !
I was thinking the same thing, add a simple opamp stage.
With a tl072 i can amplify both of my tri. waves.
I won’t have time just yet but it’s a future mod.
I built the dual lfo on a 2.5cm wide kosmo panel so there’s not much room for expansion 
Maybe i’ll just build more lfos…
your schematic look diiferent but a little like this one
i made it and it work fine ! (EDIT : the module not the schematic)
Edit 
Edit 2 : link for all steps and infos
http://familjenronnberg.se/~niklas/diy/eurorack/lfo/
Hi!
I actually saw your design yesterday, thanks for your input!
I’ll save it in my hard drive, looks good.
I certainly expressed myself badly, I corrected my topic, I realized the module but not the schematic 
Well, that’s what the circuit does 
The part to the left is an integrator that charges (or discharges) the capacitor, the part to the right a comparator that switches the integrator polarity when the input hits zero. The exact point where that happens depends on the resistors in the feedback loop. You can tweak the resistor values a bit, but adding an extra buffer is probably easier.
Simulation of this “100M” LFO tells me not only is the triangle amplitude smaller, which you can fix with a gain stage, but it’s frequency dependent, which you can’t. A rather bad characteristic for an oscillator to have. The Haillant LFO’s triangle wave is larger (I’m getting about ±8 V) and doesn’t depend on frequency.
