Duo-Phase Square Wave Mod??

moosapotamus

moosapotamus

Member
@Robert - Since the Bi-Phase originally had a sine/square selector for each of the LFOs, was wondering if you explored doing the same for the Duo-Phase.
https://www.pedalpcb.com/product/duophase/

My cheap o-scope shows a triangle LFO in the Duo-Phase. I poked around a little but could not find a square wave anywhere in the circuit. So, looking for a triangle to square wave converter led me to the single opamp differentiator circuit. Before I consider trying to figure out component values for the diff amp, can anyone smarter than I say if this is a worthwhile path to take? Or, might there be a better approach to adding a tri/sqr switch? Thx!
 
I'll pass on the beh... :rolleyes:
Anyway, I already have a few other mods wired up to the Duo board, so I'm sticking with that.

According to this... https://www.electronics-tutorials.ws/opamp/opamp_7.html ...a single opamp can be configured as a differentiator which appears to be capable of converting a triangle wave to a square wave. I just don't know what component values to use. I mean, I could probably deal with the math, but deciphering the symbols and getting the units right is probably where I would need some help. But, if workable, there is one unused opamp in the Duo that might could at least be used to add a sin/sqr switch to just one section.

Just looking for educated opinions on whether or not this is worth pursuing. And, if so, some advice on setup/component values.
 
Thanks for that, Betty Wont! Dead End FX schemes are so hard to read. But that was a big help! Just a resistor and a cap. The Lola is +/-15V and the Duo is +9V. With the values used in the Lola, I got what looked like a LOG transformation of the triangle in the Duo (shark fins). Decreased the cap from 2u2 down to 47n and got a decent looking square wave. Hope it sounds as good as it looks on my little jtec o-scope. Thanks, again!
 
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