The magnetic amplifier is an electromagnetic device for amplifying electrical signals. It uses a non-linear property of a certain class of transformer cores. It was invented early in the 20th century, and was used as an alternative to vacuum tube amplifiers where robustness and high current capacity were required. It has now been almost superseded by the transistor-based amplifier, except in a few extremely demanding military applications.

However while on this subject of the magnetic amplifier,, The "Magnetic-Field" type of Amplifiers that are the CLASS-"H" TYPE... BETTER KNOWN AS A MAGNETIC-FIELD TYPE. Bob Carver is the guy who perfected this type of amplifier ,, bar-none.. and Bob Carver has sold these ultra-light-per-watt, by the thousands VIA his companys,, Carver audio,{now-closed}; Carver-Professional; and his latest company "Sunfire"..