[sdiy] MS-20 Filter Clone Queries

[Aaron Lanterman]

On Dec 2, 2008, at 9:32 PM, Kyle Stephens wrote:

> Bearing that in mind, and using my extensive graphics skills, let me  
> ask if this would work:
>
> http://i10.photobucket.com/albums/a102/erschlagener/expo.jpg
> (R5 that I labeled tempco would be glued to the LM394 pair)

What you've drawn is basically the same as what you mention here:

http://www.uni-bonn.de/~uzs159/expo_tutorial/fig3.png

which is a current sink, not a current source. It won't do what you  
want.

The way to see this is to follow the arrow on the transistors you've  
drawn; they point away from the OTAs. Those transistors will not want  
to push current into the OTAs like you want them to, they will want to  
try to pull current out of it.

- Aaron