"Several cyclotron-based high intensity accelerators have been studied in the framework of the Energy Amplifier (EA) project proposed by Prof. C. Rubbia [1]. Among them, two basic designs are presented: a 380 MeV separated sector cyclotron delivering a high intensity proton beam to a target or to a booster accelerator and a low injection energy stand-alone H-2(+) cyclotron producing 110 MeV protons, extracted by stripping, available for further acceleration in a cyclotron or a superconducting linac structure. Specific aspects in the methods used for the design of these cyclotrons are also briefly described. [1] C. Rubbia, J.A. Rubio, S. Buono, F. Carminati, N. Fiétier, J. Galvez, C. Geles, Y. Kadi, R. Klapisch, P. Mandrillon, J.P. Revol and Ch. Roche, Conceptual design of a fast neutron operated high power energy amplifier,CERN Internal Report [CERN-AT-95-44 ET] (September 1995)."