Yes... but I push a pair of output transformers with mine, and use that to drive my low-Z Grados and K701. Thats (IMHO) a better solution (far better with the Grados), being that it presents the tubes with an optimal high impedance load. DV (for whatever reason) under-spec'd capacitance of the earlier 337 models. It was something they recognized and addressed with re-released designs.
Threads of interest for those into DIY...
Theres some excellent OT discussions in this thread here, and some detailed FR and THD analysis by Elliottstudio in the latter posts:
very smart and cool solution, good work!