[sdiy] LM13700 VCA circuit

[Ryan Williams]

One more question.

I'm trying to reduce the oscillation (atleast I think thats what it is). 
I found that using an OP275 helped alot although I'm not sure how good 
that amp is for DC. I thought I remembered reading somewhere that long 
wires around an opamps feedback path will cause the oscillation. is that 
right? currently the LM13700 is pretty far away from the opamp because 
it's on a breadboard.

-ryan

Ryan Williams wrote:
> hi all,
> 
> A while back I thought of a VCA circuit that uses the LM13700. both 
> sections are used and the first is in the feedback loop of an opamp. The 
> idea is to compensate for the non-linearity. the output of the opamp 
> inputs into the second OTA also. I noticed whole lot of high frequency 
> oscillation, most of this was fixed with a 100pF cap also in the 
> feedback loop.