  We give a brief review of the cohomological Hall algebra CoHA $\mathcal{H}$
and the K-theoretical Hall algebra KHA $\mathcal{R}$ associated to quivers. In
the case of symmetric quivers, we show that there exists a homomorphism of
algebras (obtained from a Chern character map) $\mathcal{R}\to
\hat{\mathcal{H}}^{\sigma}$ where $\hat{\mathcal{H}}^{\sigma}$ is a Zhang twist
of the completion of $\mathcal{H}$. Moreover, we establish the equivalence of
categories of ``locally finite'' graded modules
$\hat{\mathcal{H}}^{\sigma}-{\rm Mod}_{lf}\simeq \mathcal{R}_{\mathbb Q}-{\rm
Mod}_{lf}$. Examples of locally finite $\hat{\mathcal{H}}^{\sigma}$-, resp.
$\mathcal{R}_{\mathbb Q}$- modules appear naturally as the cohomology, resp.
K-theory, of framed moduli spaces of quivers.
