Speakers with an efficiency rating of 92 dbs only need an amp of 2.5 watts to reach a listening level of 96 dbs in a moderately sized room and I hope no one on this forum listens at prolonged levels of 96 dbs.

A single ended triode ( S.E.T.) is the simplest circuit design there is and uses the least number of parts. It is also one of oldest designs dating back to the 1920's. Typically there is just a driver stage coupled to a single output. Triodes do not require negative feedback, something found in most push-pull circuits, solid state or tube. Feedback creates time smear and a 2-D soundstage.

SET's are the easiest way to achieve a liquid sound that becomes holographic with stunning clarity and detail.