class AB audio amp clipping vs. heat
As the output voltage increases, the voltage dropped across the output transistors decreases, but the output current increases.

https://www.updatemydynaco.com/documents/Class_B_Amplifier_Dissipation_Calculations.pdf

Gives the equation for sinusoidal output

P = Vcc * 0.45 * Vout/R_L - Vout^2/R_L