Output Noise Floor
Output Noise Floor describes the residual unwanted voltage present at a power supply’s output.
The figure may include noise or ripple over a stated frequency range. Units, bandwidth, load and measurement method matter: an RMS reading and a peak-to-peak value are not directly interchangeable. A low number without those conditions is incomplete information.
Output Noise Floor — Power Supply
Compare supplies at the intended output voltage and a relevant load, using equivalent measurement conditions. Different frequency bands or filtering in the test setup can produce different figures for the same output. The specification should identify what was included in the measurement.
Power-supply output noise is not the same as noise measured at the audio output of the connected device. That device’s circuitry and its response to supply disturbances also matter. A lower supply-noise figure therefore does not by itself prove an audible improvement. Keep it alongside regulation, current capacity and compatibility rather than using it as the only selection criterion.