This page has a few calculators that will help you to pick optimal component values for the PPA’s bass boost circuit.
These calculators are based on the formulas derived in this Head-Fi thread.
ƒc — The frequency at which the boost is +3 dB; the corner frequency of the filter. Below this frequency, the PPA bass boost increases by 6 dB each time you divide the frequency in half, up to the point where the shelving action kicks in.
ƒs — The frequency at which the boost curve is 3 dB below the maximum boost value; the shelving frequency of the filter.
ƒo — Frequency where the gain is half the total boost. Used when boost is 6 dB or less, since ƒc and ƒs cross each other at this point.
This calculator will help you pick a C7 value given the ƒc and the R3, R4 and R7 values. The answer will not be rounded off to a standard value, since different capacitor lines have different standard values.
You may use power notation for the resistors: 120K, 1.0M, etc. The power suffix can be uppercase or lowercase.
The formula for this is:
The formulæ for this are:
|Updated Sun Jan 18 2015 04:24 MST||Go back to The PPA Project||Go to my home page|