  We report the propagation of fast wavepackets in classical non-Hermitian
lattices, where the group velocity is controlled by the non-Hermiticity
parameters, and can be made higher than in the Hermitian counterpart.
Specifically, we obtain a square root dependence of the group velocity on the
gain/loss parameter, similarly to the dependence of quantum wavepackets in
stretched graphene-like lattices subjected to gain and loss. We derive a
targeted mapping from the quantum to the classical Hamiltonian to realize this
phenomenon in a dynamically stable form. As a result, fast wavepackets of any
frequency supported by the lattice are propagating in time domain with a
non-growing amplitude. We demonstrate the system experimentally in a
topoelectrical metamaterial, where the non-Hermiticity is generated by embedded
operational amplifiers in a feedback setup. Our design paves the way to realize
increased group velocities, and other wave phenomena inspired by quantum
systems in a form that preserves the original system properties, while
supporting an inherently stable dynamics.
