20 watts, which seems to be the Due Venti's rating, is likely not enough for the TSM-Mmi, in my experience. The Stingray offers the option of 18-20w in triode or 36-40 watts in ultralinear. As much as I like the sound of triode power (I also run a 2A3 amp in another system), I found it to be inadequate in my admittedly large room. The midrange is wonderful but the top and bottom ends get a bit ragged. Ultraliner, though, sounds extremely good through the whole sonic band. Of course, YMMV.
