3rd order Sallen-Key High-pass Filter

Hi all,

I simulated a 3rd order Sallen-Key High-pass Filter and got the frequency response shown below (Fc = 6Hz)
Now I built the same circuit in practice, but I am noticing that at around 10Hz the output signal is being amplified, with the most likely cause being that the frequency response i is slightly overshooting in this region. What could be causing this when on simulation and on OKAWA Electric Design website it did not show any overshoot ?

adrianvon said:

What could be causing this

Click to expand...

Likely component tolerances or an incorrect component value.

To reduce the overshoot try increasing the value of R3.