I have revised the R-C filter calculator in the Lab Notebook so that it can work out the value of any of the 3 parameters if you input the other two. For example, enter the resistor and capacitor values and it will tell you the cutoff frequency, or put in the resistor value and the frequency that you want, and it will calculate what capacitor to use.
This is a high pass filter and you will probably recognize it as being similar to the input of the mini-booster or a jfet amplifier. Frequencies below the cutoff are rejected and those hgher will be passed on to the circuit. If you input the values from the mini-booster, 1000000 ohms and 0.05uF, the calculator will tell you the lowest frequency that can get through.
Try the values from the AMZ Mosfet Boost to see its low end response.
The low pass filter rejects frequencies above the cutoff corner and passes those below. An example of this type of filter in a guitar pedal is the R-C combination that follows the clipping stage of the Tube Screamer. The values of 1000 ohms and 0.22uF will tell you the highest frequency that is passed unattenuated, and might surprise you.
The low pass removes high frequencies that can contribute harshness to the sound. Try the values from the Proco Rat tone control in the calculator to find out its range.
Remember that one of the data fields in the calculator must be empty. Use the “Clear Form” button to start a fresh calculation, or erase one field manually before recalculating.