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60W RMS per channel at 1% THD

We’ve measured the output power of the PiFi-240 amplifier, and it’s capable of a sustained 60W RMS per channel into 4 ohms at <1%THD.  It won’t do this indefinitely without additional heatsinking – the amplifier chips are generating about 6W of heat each at this level of output and the PCB is effectively a 20-25 °C/W heatsink as it stands, which is insufficient to keep the amplifier temperature under the 150°C at which the thermal cutout operates. But it will deliver this amount of power for several seconds (we’ll know more once we’ve taken some detailed thermal measurements) which is way longer than required for music transients.

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Driver code available

The driver for the PiFi-240 amplifier’s now available in the Raspian source tree – many thanks to Phil Elwell for patiently walking us through the process.

We’ve also been taking some measurements just to verify its performance, and it’s where it should be according to the datasheets – THD+N is <0.05% at 1W across the board.  Next up is to measure its thermal performance – how its temperature in still air changes with average power output – and to verify the peak power output available.