In the chip amp forums, there is a train of thought that you need
regulation to take the 3875 much above 20 watts for a less sensitive
speaker as the power supply ripple starts to be heard whereas the
chip's amazing ripple rejection does the job below the voltage where
the power is becoming more intermittent due to the lack of power
supply smoothing capacitance.

Everybody seems to agree that simply adding capacitance to the
unregulated amp dulls the music. I'm not knowledgable enough to
assess this position, but I sure like them on the Pi's.

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