BraedBoard Project - The Triangle Buddy Inverting Amp

Happy to see more people jumping on the BrAEdboard & DIY! Congratulations on the good work! Ray Wilson's book is high on my wishlist for reading, I've built/used some of his designs from his excellent website already.

In order to help with your minor problems, could you draw up a raw schematic of your build? It's always hard to see the connections with just a breadboard picture. I suppose it has something to do with your capacitors bias, but can't be sure. What I mean with that, is that its best to have a large resistor going between virtual ground and the opamp side of your decoupling cap. This so your capacitors plate is 'standard charged' at 2.5V and it oscillates around 2.5V. Hard to see on the breadboard, I see you have made the 2.5V reference, but I'm not sure to which different points you connected it.

A lot of the AE modular sounds will also be hard clipped at 2x amplification (no fear, it's not dangerous  ), but I think you already have a pot set up as attenuator?

Thanks for the drawing, looks good! Happy it worked for making the cap work consistently already.

For the attenuation: your pot should also go to 2.5V instead of to 0V. This because you want your attenuation to be 'symmetrical' around your Waves oscillation. Not 100% sure it will solved the problem, but it's the only thing i can think of for now.

I think you're right, its some kind of Buffer Follower or something. I'm going to play around with it and try to figure our exactly what I did. Thanks!

So I'm getting confused, is this an amplifier that also inverts your wave form? Do you have some audio demo?

The most stable analog buffer/amp configuration always inverts the waveform, but the human ear can't hear that unless you combine the original uninverted signal with the inverted one. Stuff like mixers, fx,.. often have multiple inversions inside, just as a side product of all buffer stages.

thehatghost great job! Congratulations on the succesfull design 😄

The square wave in AE is already at the loudest possible volume, because it oscillates between 0 - 5V. So it's expected that you won't be able to hear any amplification.

And on the original prototype: if it sounds good, i'd keep it 😉

I did not know that, thanks for your explanation. It makes indeed sense that the human ear won't hear the difference between a waveform and its inversion, except when you sum them together for it's the sound of silence....

Interesting on the caps! It makes sense that a bigger Cap let's through more bass, but i'd expect that the input Cap would filter out that bass already in the first place. Ofc i trust both your ears & Ray Wilson, but it's suprising nonetheless! Regarding the noise: ceramic caps introduce noise when working with oscillations (eg audio but also other stuff), I've built guitar pedals with just ceramics in the past and some are really unuseable because of that (also because eg a fuzz pedal van have x50 gain or something, so you just amplify the noise too).

Regarding the resistors: that was also my thought, but even better that you figured out yourself!