Simple Capacitance Multiplier Power Supply Filter By Rod Elliott (Gerber & PDF) Download on Google Drive

This is an easy design to build, but requires great care to ensure that ripple currents are not superimposed on the output because of bad grounding or power wiring practices. The schematic is drawn to show how the grounds of the various components should be interconnected, using a 'star' topology. If this is not followed, then excessive hum will be the result.
Normally, a schematic diagram is intended to show the electrical connections, rather than the physical circuit layout. This diagram is an exception, and the physical layout should match the schematic (in as much as that is possible, at least). Surprisingly little resistance is needed across a high current connection to produce a measurable performance degradation.

Using A Capacitance Multiplier Filter With Class-AB Amps

Note that this circuit is quite suitable for Class-AB amplifiers, but since their current requirements vary so widely, adding a much larger capacitance to the output is a must. The diode is recommended as shown to prevent the possibility of reverse biasing (and destroying) the transistor(s) when power is removed.

The benefits of such filtering are subtle, but may be worth the effort. Many power amps are now built with truly massive capacitance after the rectifier. This reduces hum which is introduced into the signal during loud passages. In theory, this is inaudible - but if so, why do amps with very large capacitor banks always seem to sound better? (Or so the reviewers keep telling us.)
If you are desirous of trying this circuit with a Class-AB amp, I would strongly recommend that the input to output voltage differential be increased (Var 10K)