How safe are solid-state replacement rectifier modules?
You should be wary of blindly plugging a solid-state module into a tube rectifier socket. A tube rectifier will drop about 50V to 60V and limit the maximum voltage on the input filter cap. Solid-state diodes drop only half a volt, so the filter may be subject to overvoltage. A module can be made from 50V, 50W zener diodes that maintain a constant voltage drop and protect the cap. The only benefit over a tube rectifier is reliability. The only drawback is that the inherent slow turn-on of the valve, due to warm-up, is lost.
