Fuse protection

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RWood
Posts: 254
Joined: Sun Jul 07, 2013 7:56 pm

Fuse protection

Post by RWood »

I found Keen's articles about fuse protecting B+ and PT supplies but having trouble finding info as to type and sourcing. Anyone using these methods of protection? I'd hate to loose a good PT or rectifier because of plate shorts (which I experienced recently when installing a new 6L6 which had shorted plates), or filter cap failure.
Thanks in advance...Randy
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David Root
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Joined: Fri Aug 04, 2006 3:00 pm
Location: Chilliwack BC

Re: Fuse protection

Post by David Root »

I only use OT B+ fuses on valuable vintage iron. Fast blow, maybe 500mA on a 50W and 800-1000mA on 100W.

HT winding fuse on a PT-again if it's vintage iron.

In a vintage amp you can use the ground switch hole for an OT fuse, otherwise it's internal. In a new build of course anywhere you want.
pdf64
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Re: Fuse protection

Post by pdf64 »

See Merlin's thoughts on the topic http://www.valvewizard.co.uk/fuses.html
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tubeswell
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Re: Fuse protection

Post by tubeswell »

As a RoT, use 250mA T fuse for each pair of EL84 or 6V6s, 500mA T fuse for each pair of EL34s or 6L6s. (You want it to be about 2 x the max current draw you'd expect more or less). YMMV
He who dies with the most tubes... wins
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