Rafael,
They are Rowland 201s. Not really a fair comparison, given the switching power supply utilized the Rowland, which is both excellent and practical. The Rowlands are only a fraction the size, weight, and cost of the Spectrons. A more fair comparison would be the Rowland 312, but I don't know if it can be used as a monoblock.
The Vandersteen 5A is relatively sensitive for a speaker of its size and capabilities. As others have mentioned, it will be driven capably by at least some 50 watt amps.
They are Rowland 201s. Not really a fair comparison, given the switching power supply utilized the Rowland, which is both excellent and practical. The Rowlands are only a fraction the size, weight, and cost of the Spectrons. A more fair comparison would be the Rowland 312, but I don't know if it can be used as a monoblock.
The Vandersteen 5A is relatively sensitive for a speaker of its size and capabilities. As others have mentioned, it will be driven capably by at least some 50 watt amps.