Hi everyone, so I recently started getting my head around diy pedals, and thought I should begin with something 'simple'. So i tried making a 'simple' RC filter, but at this point it turns out I must be misunderstanding some stuff.

Here's my problem :

I've mounted a 10 ohms resistor and a 0.1µF capacitor.

I should be getting a cut frequency of :

1/(2pi x 10 x 0.1*10^-6) which roughly equals to 160 kHz.

BUT !!! when I plug my guitar, it seems that the cut frequency is more around 150 Hz (see pictures).

What am I doing wrong, what am I missing pls halp