I had this page bookmarked a while back: https://forums.stevehoffman.tv/threads/can-an-set-amp-serve-as-a-long-term-main-amp.244368/
Typically, single ended Class A SS amps are significantly more inefficient than SET amps. Could be a difference in topologies - although inefficient, (that’s the point) a pure Class A amplifier that is solid state can provide consistent high current (into let’s say a 4ohm speaker) - that’s why you have monoblocks with huge capacitors that drive flagship speakers.
Typically, single ended Class A SS amps are significantly more inefficient than SET amps. Could be a difference in topologies - although inefficient, (that’s the point) a pure Class A amplifier that is solid state can provide consistent high current (into let’s say a 4ohm speaker) - that’s why you have monoblocks with huge capacitors that drive flagship speakers.