I'm looking for some advice on driving an 8Ω 2W speaker near full power from a 3.3v DAC. I've put together a current amplifier using a rail-to-rail op amp and two BJTs, but it's not supplying as much current as I thought it might.
In an ideal scenario, I was hoping to be able to drive the speaker up to ~1.25W, but in reality I'm only getting about 0.3W when putting 3.3v into the positive input of the op amp.
3.3V / 8Ω = 412.5mA = 1.36W
Wondering if anyone has any suggestions for improving this circuit or any alternatives. The DAC is providing a 3.3v output and my available power supply is 3.3v so I would prefer any amplifier I use to have a unity gain.