Doubt about the real power of Speaker pHAT


Hi, I’m not sure if the pHAT can deliver the 2Ws to the speaker included in the kit.

I know the amplifier is 3W (3.2 acording the MAX98357A datasheet) and the speaker is 2W.

But the high power limit only can reached with 4ohm speaker (the included is 8ohm).

The datasheet informs for example, that at 5v (page 11, graph 1) this gets 1.75W (already with 10% thd).

The test configuration uses GAIN_SLOT at 12db. The max is 15db configuration. So I dont know if the pHAT uses the gain_slot at 15db making any difference.

Acording my questions i ask: the Speaker pHAT can really drive the original speaker at 2W (even with higher THD)?



As mentioned on the product page, by default the output power is 0.45W. In general you shouldn’t run speakers at their rated maximum power, as they won’t sound very good that way. For more volume it’d be better to use a larger speaker.
If you do have a larger speaker (or don’t mind some distortion) you can increase the gain by 3dB by shorting the open solder bridge close to the amp chip, or by 6dB by soldering a 100k ohm 0603 resistor there. You could also try increasing gain in the mixer software.


Now it’s all clear, thank you!!!