Class D

High end class D TPA3255 based amp, 2X260W into 4ohm (53V version), or 2X72W into 4ohm (24V version, powered by laptop PS)

For details, see the diyaudio link below.

https://www.diyaudio.com/forums/class-d/352069-compact-tpa3255-design-pffb-single-ps.html

TPA3255 is a high performance class-D power amplifier that enables true premium sound quality with class-D efficiency. It features an advanced integrated feedback design and proprietary high speed gate driver error correction (PurePath™ UltraHD). This technology allows ultra low distortion across the audio band and superior audio quality. The device is operated in AD-mode, and can drive up to 2 x 315 W into 4-Ω load at 10% THD and 2 x 150W unclipped into 8-Ω load and features a 2 VRMS analog input interface. In addition to excellent audio performance, TPA3255 achieves both high power efficiency and very low power stage idle losses below 2.5W. This is achieved through the use of 85 mΩ MOSFETs and an optimized gate driver scheme that achieves significantly lower idle losses than typical discrete implementations.

This implementation includes Post Filter Feedback circuit, which significantly reduces distortion and influence of coil nonlinearity to the overall performance. Do not confuse it with cheap asian alternatives, this is a true high end performance device in a compact package rivalling the best in class A or AB, running from single switching power supply of 18-53.5V. Supply of 24V provides enough power already for room listening levels even with low efficiency speakers and amazing clarity and transparency, so unless you need to shake your neighbourhood down, you can run it with a laptop power brick. I am recently using it also as a silent guitar amp, because of its low EMI - no heavy power transformers around.