Any kind of a radio system utilizes differet parts that have overunity inside. This overunity is lower or higher that depends on the circuit construction used. Some of the older radios/amplifiers had better internal structure for this kind of job - asa tiny electricity generator. That means even potentiometers were done in different way. Or Chassis or mounting the cables, OK? So we can make an overall system to get higher gain that we put into, evna. All kinds of radio has this possibilities, but knowing the rule of /mattery-energy/ we can debunk that bigger tuner/amplituner is better for that purpose.
dxer