[sdiy] keeping signals seperate..avoiding noise

Derek Holzer derek at umatic.nl
Sat Nov 15 18:08:38 CET 2008

EE folks are welcome to correct me if I'm off base here, but the 
non-inverting op-amp configuration is usually high impedance, and the 
inverting setup is low impedance. So two inverting op-amps would give a 
much lower input impedance than a single non-inverting one. Basically 
you want to make it easier for the "nice" signal to travel through the 
circuit via a lower impedance than that presented to the "nasty" signal 
(love these technical terms!!!).


Dan Snazelle wrote:
> I dont really understand what you mean about lowering the input impedance. could you explain a bit how impedance might help?
> take a look at the first opamp in this schematic:
> http://www.musicfromouterspace.com/analogsynth/GUITARSYNTHAUG2007/subcommanderschempg1.gif
> i used ray's (first only) opamp as a model of how to create a non inverting input

derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
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