touch sensitive circuit

[austinb]

I am thinking about designing a circuit where you gain up and rectify a audio signal then feed that signal into a comparator with a variable threshold. Could add hysteresis to keep it from switching too much causing switching noise. This would turn on a jfet switch enabling a different variable gain feedback resistor on an opamp. This could be a petal or inside of a amp. Or this could enable a effects loop with your favorite distortion petal, (auto touch sensitive switch). What do you think and what are your ideas?

[ic-racer]

Interesting idea. The intensity of the string pluck, you know, has that peak then it tapers off pretty quickly. Seems like the circuit would only be activated at the peak of the pluck, where the signal is strongest.

[austinb]

That is where the comparator hysteresis comes in. Once the threshold is meet then the amplitude must drop farther below the threshold for it to disable the gain stage. Hysteresis is a feedback resistor on a comparator. The gain stage would have to be limited somewhat so as to not cause problems. Just to emphasize the touch sensitivity.

[drz400]

I am thinking about designing a circuit where you gain up and rectify a audio signal then feed that signal into a comparator with a variable threshold. Could add hysteresis to keep it from switching too much causing switching noise. This would turn on a jfet switch enabling a different variable gain feedback resistor on an opamp. This could be a petal or inside of a amp. Or this could enable a effects loop with your favorite distortion petal, (auto touch sensitive switch). What do you think and what are your ideas?

I do believe that Maven Peal patent covers this and is part of his "sag" circuit.

[jaysg]

I used to have a dbx compressor that had a knob that went continously from heavy compression to heavy expansion.