Yeah the PSRR of a typical LDO doesn’t to as well up in the high frequencies, but it generally still does some attenuation. I’m not an expert myself, but I’ve

Yeah the PSRR of a typical LDO doesn’t to as well up in the high frequencies, but it generally still does some attenuation. I’m not an expert myself, but I’ve read that RF noise in audio applications isn’t always okay because it can demodulate into your amplifiers. Re. Capacitance multipliers, I may be mistaken but I think they typically introduce significant positive gain at high frequencies due to the transistor parasitics. They make sense for very low frequency cut off (AC mains transformer ripple), but I’m not so sure about typical SMPS output. I would bet other filter topologies (LC, etc), would generally do better in practice. And definitely 100% on the layout. Return currents and common mode noise will get ya.