[sdiy] some diy: ssm2040 filter

[ryan williams]

René Schmitz wrote:

> Try adding a 1n (or thereabout) cap from the inverting input to the 
> output of U2B. Maybe that expo is starting to oscillate at some point. 
> (It's missing on my schemo too, sorry!)

I forgot to mention before. I already added a 2.2nF cap there as 
suggested by Scott Stites.  I did not think to check that opamp's output 
yet though, I'll take a look.  René or anyone else who has built it, if 
you know off hand, could you tell me approximately how large an input 
signal can the filter take before it starts to show distortion on the 
output?

thanks,
   ryan williams