VTL also still produces the little MB-125's. These mono's use the EL-34's , where as the ST-150 uses 6550's. The 125's may have the same power, and the Wilson may really sing w/ the EL-34. BTW, their prices are close, $5000 I believe. FWIW, the 125's also have the Triode mode like the ST-150. That said, I am not confident that either in Triode would be enough power. Perhaps it may be, but I am not sure. At the ST-150's price point, there is also some other interesting choices IMO. Maybe a C-J Premier 12, seen under 3K used, or a Quicksilver V-4.