Sugden Audio writes: “Circuit board technology has changed considerably over the fifty years Sugden Audio have been manufacturing audio equipment. Some of the biggest advancements have been the introduction of multi layered boards and surface mount components. At Sugden we still produce all our circuit boards in a traditional way with through-hole components that are hand soldered. This process allows us to choose and use components for their sound quality and performance. The component quality has also improved greatly over the years. The two circuit boards are from 1973 and 2018.”