LC Filter Calculator

Here is another nifty calculator for determining the frequency response of a LC filter circuit. This could also be useful for PSU design calculations. I used this to aid in the understanding of the determination of the 'Ultrapath' capacitor. Using an example Plitron PAT-3035-SE, with a primary inductance of 28H and an Ultrapath cap of 51uF, the frequency cutoff (not sute if it is f-3dB) is 4.2 Hz. My understanding from this, is that any audio signals above 4.2 Hz will be returned back to the cathode to ground, rather then through the PSU capacitors to ground. Doubling the capacitance to 100uF, results in a frequency cut-off of 3 Hz.