Is this a low pass filter???

[dehughes]

Lord knows what's happening here but this is what I have in my build, and I like it. It's the result of one idea being sucky but having a neat side effect that I couldn't have predicted....and actually leading to something more fun.

Is that 220k/.01uf/15k/8uf/ground thing a low pass filter of some sort? Could someone explain exactly what is happening? I could venture a guess, but it would be pretty simplified and probably wrong anyway...

Also, does the 8uf cap really do anything? That is, it's so large I wager I'd hear no difference if I connected the 15k directly to ground, right?

[Cliff Schecht]

What you've drawn is essentially the static version of a hi-cut tone pot, albeit a goofy version. The 8uF really isn't doing anything here. If you do the math, the almost 100x size of this capacitor means that it shifts the frequency response by fractions of a hertz (about .6-.7Hz). If you can hear the difference then more power to you, but my guess is you can't tell the difference with it in or out of the circuit.

It's also important to note that no matter what order these parts go in, the impedance stays the same. So if you did just a 235k resistor and a .01uF RC pair, you would have the same frequency response (minus the 8uF caps unimportant influence and parasitic stuff involved with the way the parts are laid out).

[dehughes]

Awesome. Thanks. Goofy is the perfect descriptor.

I'll go experiment with things (r.e., removing the 15k resistor and 8uf cap) and see if I can't get it simplified and more fine-tuned. Oddly enough, what this circuit needs is more of a low-cut...which I'm getting with these components as drawn in comparison to removing the 220k/.01uf/15k/8uf out of the circuit. Time to go (de)solder....