[sdiy] If you thought the LM324 was slow ...

[Grant Richter]

I was reading in the "Op-Amp Cookbook", to save power, the LM324 uses a
Class B output stage, not Class AB. So that accounts for the high crossover
distortion.
> 
> The PS-synths use LM324s in their VC-ADSRs, as a buffer for the
> integration capacitor, and as a schmitt trigger / flipflop for the
> attack phase. 
> It's a decent solution, especially as single supply operation is required,
> and the input voltage goes down to GND. No major speed issues here.
> (0.5V/us slew means 30us for 15V - fine for an envelope.)
>