A cableless high power RF or microwave amplifier may amplifies an RF or microwave signal. The amplifier may include: an input signal divider (DIV) that has a DIV input connector that receives the RF or microwave signal and that divides this input signal into multiple sub-input signals, each of which is delivered to a DIV output connector; multiple power amplifier units (PAUs), each of which has a PAU input connector that receives an RF or microwave signal and a PAU output connector that delivers an amplified version of the received RF or microwave signal; and an output signal switching combiner unit (SCU) that has multiple SCU input connectors and that coherently sums the signals at the multiple SCU input connectors and delivers this to an SCU output connector. Each of the PAU output connectors may be electrically connected to a different one of the SCU input connectors without connecting cables.