Anyone ever tries to use the heavy duty air core indutcors used for speaker crossovers for PWM filtering? They are wound with 15 guage wire with air cores and are compact. The larger inductances required for higher impedance filters make solenoid single layer inductors very large. Parts express has a large number of sizes and also large high voltage polypro capacitors.
I am looking at a 100 watt amp and the filter will need to be around 20 ohms for a 2.5 amp load at 50 volts.