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The scattering dependence of electroacoustic amplification is studied in this paper together with the effect of a longitudinal magnetic field in the extreme quantum limit, when only the lowest Landau level is occupied by the electrons. As in the case of absorption, the magnetic field enters this theory only through its effect on the electronic relaxation time. A numerical-example is discussed for the two cases in which the electronic relaxation time is given bya) acoustic-phonon scattering andb) ionized-impurity scattering. At frequencies outside the domain of validity of the local theory (ql τ 1), the absorptionamplification coefficient is found to be strongly scattering dependent. In particular the threshold value of the drift velocity to obtain amplification may be very different from, and even one order of magnitude higher than, the sound velocity.