I doubt that any of the classic, low-powered triode tubes (300b, 2a3, 45) would work well with your speaker, even in parallel SET configuration (more than one tube per channel). You would really have to look at a high voltage transmitter tube SET (845, 211, GM70), and well-built examples are pricey and don't quite deliver the sound that is prized by low-power SET fans.
Atmasphere refrained from touting the approach his products use, but, certainly an output transformerless tube amp is something worth looking into. These can deliver considerably more power and a model might be suitable for use with the Venere. Good OTLs are very exciting sounding: great dynamics and a lively, forward sound. I think that kind of presentation would help the Venere.
