[sdiy] The sound of various Op-Amps

[jhaible at debitel.net]

> > Try 10nF across the 10k feedback resistor.
> 
> Yes, this would work. Effectively shorting out Rf at high frequencies.
> But since the app I had in mind was a supposed upgrade of an existing
> circuit, I didn't want to add any extra components. In the end I settled
> for a LF412.
> 
> I'm still not entirely sure why it happened though. Maybe there's some
> appreciable input capacitance across pins 2 and 3. [inv and non
> inverting inputs]

Yes, of course the input capacitance will form a pole
together with the feedback resistor! This doesn't hurt as
much if you have a slow opamp (internal pole still being 
dominant for "medium" value resistors), but if you have
a fast opamp, you also need low impedance.

JH.

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