Guys, this is part of the issue I am asking about in my other thread...

....I am trying to be proactive here. I want/need to buy some 15-20 amp fuses for my B&K amplifiers. These are the kind that fit into the fuse holder on the back and screw in. Once upon a time, these were easy to find. Now, not so much. The fuse has to fit into the screw-in receptical on the amplifier. Any idea where I could get new fuses that will do the trick?


Might be worth your while to check the owner's manual to make sure you (or someone else, if you bought used) didn't "accidentally" replace the fuses with the wrong values at some point in the past.  Nothing worse than having your equipment (or your house!) burn up if the fuse doesn't blow when needed. 
From the pictures online it looks like a 3AG fuse holder.  The cap unscrews and the fuse is held in a cup on the cap.  The 3AG fuses are 1/4" diameter x 1 1/4" long.  Which are just about the universal glass fuses used.
Usually they manufacture will mark ampere rating by the holders.  If not check the manual. Or
Remove the old fuses and look around the silver ends of the fuse. Usually engraved is 3AG, 250V and some number with an A after it.  This is the amp rating of the fuse.

However!   Power input fuses may be a "slow blow" type to handle turn-on Inrush current. You can tell a slo blo fuse by the extra stuff inside the fuse. The standard fuse just has a wire running across.  Your amplifier may have been supplied with like an 8amp slo blo input fuse. Someone replace it with a standard 8 amp and it blows frequently upon turn-on. If not immediately. So they upped the rating of the fuse. Wrong way to go.

Search ebay for 3AG fuses.

FYI   Also available are Fast Blow fuses. Those fuses have a white ceramic cover instead of glass.

1- user manual (Hifiengine has many online) for OEM part value.

2- eBay, Amazon, Zoro, Grainger, lots of sources.

2 major manufacturers of automotive and audio fuses (generally 1x1/4” or 5x25mm although 20mm length are also common) include Buss and Littelfuse.

3- fast or slow-blow are available in glass or ceramic packages.

4- as mentioned previously, power supply fuses are usually of more robust slow-blow, audio/speaker side of the fast-blow variety.

5- for some examples:

6- always have spares. This almost guarantees you’ll never need one.

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also, find a few for sale on hifishark, perhaps someone here, write and ask if they have the manual with the spec,

or, original owner, never changed fuse, if they would look and see what fuses they have in there..