I have driven the Duntech Sovereign with a pair of VTL ichiban 150 watt triodes after using AR 300,Sectral and other Solid state amps. I feel the EL34 tube is ideal and could recommend only the Rosenblitz 300w OTL amps as an alternative. I have access to many exotic, high end speakers and driver combinations and the only combination to challenge these could be the Tannoy WRSE speaker if the room is of sufficient volume and dimension.