Tubed-amp power-supply question


Do we have any audio EEs here?

In a ‘pi’ filter with 2 caps connected by a choke, I’ve seen amps with some hi-quality (‘propylene and ‘styrene) capacitance in parallel with the choke. What’s the purpose of that?
jeffreybehr
A cap in parallel with a choke creates a notch filter, one that is tuned to and has a very high impedance to a narrow range of frequencies. By choosing values that produce a filter centered at the ripple frequency of the power supply, usually 60 or 120Hz in the US, the ripple voltage that passes through is reduced.
Herman,
Awesome answer!
Awesome indeed. TYVM.