  In warm inflation, dissipation due to the interactions of the inflaton field
to other light degrees of freedom leads naturally to the enhancement of the
primordial spectrum during the last 10-20 efolds of inflation. We study this
effect in a variant of the Warm Little Inflaton model, where the inflaton
couples to light scalars, with a quartic chaotic potential. These large
fluctuations on re-entry will form light, evaporating Primordial Black Holes,
with masses lighter than $10^6$ g. But at the same time they will act as a
source for the tensors at second order. The enhancement is maximal near the end
of inflation, which result in a spectral density of Gravitational Waves (GW)
peaked at frequencies $f \sim O(10^3-10^5)$ Hz today, and with an amplitude
$\Omega_{GW} \sim 10^{-10}-10^{-8}$. Although the frequency range is outside
the reach of present and planned GW detectors, it might be reached in future
high-frequency gravitational waves detectors, designed to search for
cosmological stochastic GW backgrounds above MHz frequencies.
