It doesn't have to necessarily be different technology. Schiit got into trouble because the output transistors were too close to other things. For mass production one needs a torque driver too make sure the transistors are bolted to the heat sinks properly for correct heat dissipation. No one made a right angle torque tool thin enough to fit in the space. Iirc Jason built the prototype in a different order. Once proper assembly line order was considered the problem appeared. Building precision stuff ain't always easy.