To get various characteristic of an auto wah/quack effect, we need a flexible control of the envelope detection characteristic. Some playing styles need slow attack but fast decay, but some others don’t. Employing the detector circuit presented in our previous article Envelope Detector Circuit with Separate Attack/Rise and Decay/Release Time Settings, here we present the improvement of the previous auto wah/quack effect circuit to accommodate the envelope’s attack/rise time and decay/release time adjustments.
The circuit uses two LM324 operational amplifier integrated circuit chips, contains 8 operational amplifiers units in total. The supply voltage is 9V, a common power supply in the guitar effect chain. The performance, how it sounds can be seen in the following Youtube video: