[sdiy] some diy: ssm2040 filter

[ryan williams]

sucess,

thanks to an off list message from Tim Stinchcombe I now have a properly 
working filter. and it sounds great!  I love the distorted sound.  I 
didn't think to check how much bias current sets the cutoff to 20KHz.  a 
combination of that and the limiting resistor wasn't big enough (and I 
made it even smaller trying to fix it. heh).  Atleast I was working in 
the right part of the circuit though. so the pop sound was when the ota 
bias current was going from a few hundred uA to some mA with a tiny 
touch of the pot.  I didn't realize that it was going beyond the audio 
range because the pot was so sensitive.  I changed the offset resistor 
and it works great now.  I feel a bit silly though.

thanks for all the help and suggestions!  just a few more input/output 
and feedback gain resistor changes and it will be going perfectly.

ryan williams