The Sun amps and particularly their single ended types are VERY simple designs with most if not all, point to point wiring construction and minimal parts count.... Which largely attributes to their lovely sound quality when mated to speakers adhering to similar design philosophy.
Their schematics are also readily found on the Internet and as such any tech with even a basic familiarity of electronic/tube circuitry should have no difficulty resolving any issues, or returning them to original configuration (as they are often modified).
Their schematics are also readily found on the Internet and as such any tech with even a basic familiarity of electronic/tube circuitry should have no difficulty resolving any issues, or returning them to original configuration (as they are often modified).