What is the purpose of C6 in this diff amp circuit?
I have been told it's an RF filter consisting of R6 and C6.
If true, what formula do I use to determine the turnover frequency of that filter?
Reason I'm asking is that the amp had too much gain and I changed R6 to 4.2K to reduce the gain. Since I changed R6, do I now need to change C6? If yes, how do I determine what value to change C6 to?