I've found that although the Alphas are efficient they need power to move air in free space. They sound best with 75 to 100 watts per channel.
With the Betsy/Alphas I drive the Alphas with an old Denon AV receiver that I bought from an owner who was upgrading to a new HDMI receiver. It costs me all of $35 and makes around 100 watts in 2 channel mode. It's nice to have a remote to tune the bass from my listening chair.
