Tube DIY Asylum

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RE: Bringing down the ripple......?

Posted by Tre' on July 17, 2023 at 08:22:39:
"usually sized at maximum tube current draw"

but if you are not drawing that much current then the cap can be bigger without exceeding the max peak repetitive current rating of the tube.

so it is not the value of the cap that can not be exceeded, it is the value of the peak repetitive current that can not be exceeded.

Some of the data sheets for the 5r4 shows 4uf as the max value for the input capacitor but that is for the situation shown in that data sheet.

I can show you examples of circuits with voltages and load current draws where 220uf is just fine and other circuits with voltages and load current draws where 4uf is too much.

There is no fixed capacitor value that is max. The voltage and load current draw determines how large the input cap can be without exceeding the peak repetitive current rating of the rectifier tube.

Again, it is the peak repetitive current rating of the tube that can not be exceeded.

Tre'