Just an added note to my last post.
For those of you that posted you increased the size of your audio grade fuse by one size because the correct size blew, here is something you may want to consider. When the designer/manufacture sizes the ampere rating of the fuse to protect his equipment the ampere rating is usually higher than the power consumption of the equipment. It might be 110%, 125%, 150% 175%, or 250%. It can be as high as 300% of actual FLA of the piece of equipment and still meet electrical safety standards.
If you look on the back panel of the piece of equipment the manufacture should show the power consumption of the piece of the equipment and the AC voltage rating it is rated at.
If it is given in watts or Va just divide the watts/Va by the voltage.
Example of a tube power amp
330 watts @ 120V.
330/120 = 2.75 amps FLA.
Size of the line fuse?
For a tube power amp it will more than likely be a slo-blo fuse.
Ampere rating, depending on how beefy the power supply is at least 125% of the FLA.
125% of 2.75A = 3.4 amps
150% of 2.75A = 4.1 amps
175% of 2.75A = 4.8 amps
Good chance the fuse will be a slo-blo 4 amp 250v fuse.
What is the percentage if the ampere rating is increased by 1 amp? 4A to a 5A fuse.
175% of 2.75A = 4.8A
185% of 2.75A = 5.09A
So you may be increasing the lag, delay, time for startup inrush current so the fuse does not blow, but what are you doing for the overload current rating protection of the piece of equipment?
.
For those of you that posted you increased the size of your audio grade fuse by one size because the correct size blew, here is something you may want to consider. When the designer/manufacture sizes the ampere rating of the fuse to protect his equipment the ampere rating is usually higher than the power consumption of the equipment. It might be 110%, 125%, 150% 175%, or 250%. It can be as high as 300% of actual FLA of the piece of equipment and still meet electrical safety standards.
If you look on the back panel of the piece of equipment the manufacture should show the power consumption of the piece of the equipment and the AC voltage rating it is rated at.
If it is given in watts or Va just divide the watts/Va by the voltage.
Example of a tube power amp
330 watts @ 120V.
330/120 = 2.75 amps FLA.
Size of the line fuse?
For a tube power amp it will more than likely be a slo-blo fuse.
Ampere rating, depending on how beefy the power supply is at least 125% of the FLA.
125% of 2.75A = 3.4 amps
150% of 2.75A = 4.1 amps
175% of 2.75A = 4.8 amps
Good chance the fuse will be a slo-blo 4 amp 250v fuse.
What is the percentage if the ampere rating is increased by 1 amp? 4A to a 5A fuse.
175% of 2.75A = 4.8A
185% of 2.75A = 5.09A
So you may be increasing the lag, delay, time for startup inrush current so the fuse does not blow, but what are you doing for the overload current rating protection of the piece of equipment?
.