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I am having trouble understanding the feedback loop for this gain stage for a guitar distortion pedal. I am completely new to electronics. I tried looking for similar looking RC filter topology and have found none. I though at first that it might be a twin t notch filter, but it isn't that one.
Based on what I have read, \$C_4\$ is used for power supply decoupling. What would be the correct formula for its frequency cutoff?
$$ {1\over 2\pi R_6C_4} $$
or
$$ {1\over 2\pi R_{ps}C_4}; R_{ps} = (R_3+R_4+R_6) $$
What is the function of \$C_2\$? How do I simplify the feedback loop resistance only, without the filter for the power supply decoupling? Sorry if I am doing it all wrong. Any pointers would be greatly appreciated. Thank you.
