NOYITO DC LC Filter DC EMI Power Filter 0 to 50V 2A 4A 10A 20A Filtering Board (2A)

Probably no real world configuration of inductors and capacitors is going to do any better. Useful for filtering out electrical noise from a DC power supply (like a computer, wall wart, or car).

Product as pictured but no loss of high frequency noise in guitar pedal. Joyo ZGP reduced x10

This 3 stage filtering board does a great job of cleaning up the DC voltage from a switching power supply. I had a 3 volt DC switching power supply for a radio. I wanted to use the radio's audio headphone output to go into another device on a permanent basis. With the DC power supply, the headphone output had a fair amount of static and general noise. On battery only, the radio was perfectly clean sounding. Using this filtering board, the noise and static level was eliminated from the power supply. I also added a ferrite core with 3 loops in it after the filtering board (which made very very little difference, but just icing on the cake). As long as you use the correct one for the amount of current you are using (always over the current never under), and keeping the supply voltage at half or below, this product will do a very good job of cleaning up the output voltage of your switching power supply.

it doesn't do anything