[MrFixr55]

Hi Mark,

Sorry, juggling chainsaws. Rich answered your question well. My preference for fast fuses with current ratings about 1.4X the advertised current is based on the fact that tube style rectifiers will provide a soft start to the power supply, coupled with the relatively small filter caps used in vintage radios. On the other hand, cold tube heaters draw a high amount of current. I will defer to others who have restored more radios than I have.

Solid state radios or tube amps with solid state rectifiers and large caps have a high inrush current and often, a slow fuse is specified. The issue is how long a part such as a rectifier or transformer winding can take an excess load. Solid state amps usually have speaker fuses. Replace them with exactly what the manufacturer recommends. These are usually fast fuses. However, nothing blows faster than an output transistor. It will short, thereby blowing the fuse. I repaired many an amp when I was a kid because the users would put about four 8 Ohm speakers in parallel and blast the thing or be sloppy on the speaker connections.