  We investigate the enhancement of the power spectra in models with multiple
scalar fields large enough to produce primordial black holes. We present
analytic solutions for the perturbations in the case of constant turns without
the need for an effective field theory for the first time and clarify the role
of the Hubble friction that has been overlooked previously. For an arbitrary
number of fields we derive the criteria that can lead to an exponential
amplification of the curvature perturbation on subhorizon scales, while leaving
the perturbations stable on superhorizon scales. Finally, we apply our results
on a three-field generalization of the "ultra-light" scenario and show how the
presence of field-space torsion can yield distinct observables compared to the
two-field case.
