Fast acting fuses

I have a pair of JBL model CF120 speakers. Yesterday while listening to the system a ground wire came loose and the next thing I realized the right woofer was out. These speakers are protected by a couple of TC 2.5A fuses. One of these fuses screws into a threaded holder, (and it was open) and the other clips into a two prong connector. Since I didn't have a small size TC fuse I swapped the good fuse into the threaded holder and I soldered, (piggy backed) a 2.5A AGC type with pigtails onto the open TC fuse and clipped it back into the socket.

So the TC fuse indeed protected the speaker, and I'm very grateful for that.. I fixed the ground problem and until I can pick up the correct fuses this will work. However I was wondering if this TC type fuse is anything special? They are two different physical sizes but how does it compare electrically with an AGC type? In theory would AGC fuses be adequate protection for these speakers? I have boxes of them.

One interesting thing I thought I'd mention was that coming right out of each speaker output on the amplifier there is a 2 amp MDX fuse that never opened. I know that the MDX is some type of time delay. Don't even know why that was in there. I would appreciate any comments on this. Thanks, Lenny

 

[Phil Allison]

captainvi...@gmail.com wrote:

I have a pair of JBL model CF120 speakers. Yesterday while listening to the system a ground wire came loose and the next thing I realized the right woofer was out. These speakers are protected by a couple of TC 2.5A fuses. One of these fuses screws into a threaded holder, (and it was open) and the other clips into a two prong connector. Since I didn't have a small size TC fuse I swapped the good fuse into the threaded holder and I soldered, (piggy backed) a 2.5A AGC type with pigtails onto the open TC fuse and clipped it back into the socket.

So the TC fuse indeed protected the speaker, and I'm very grateful for that. I fixed the ground problem and until I can pick up the correct fuses this will work. However I was wondering if this TC type fuse is anything special? They are two different physical sizes but how does it compare electrically with an AGC type? In theory would AGC fuses be adequate protection for these speakers? I have boxes of them.

One interesting thing I thought I'd mention was that coming right out of each speaker output on the amplifier there is a 2 amp MDX fuse that never opened. I know that the MDX is some type of time delay. Don't even know why that was in there. I would appreciate any comments on this. Thanks, Lenny

** JBL say the CF120 uses a 2.5 amp slo-blo fuse.

MDX are obsolete and replaced by MDL.

Lots of other options exist using T or TT fuses.

AGC is a fast type, same a F types and will bow too easily.


.... Phil

 

On Friday, February 27, 2015 at 2:37:58 PM UTC-5, captainvi...@gmail.com wrote:

I have a pair of JBL model CF120 speakers. Yesterday while listening to the system a ground wire came loose and the next thing I realized the right woofer was out. These speakers are protected by a couple of TC 2.5A fuses. One of these fuses screws into a threaded holder, (and it was open) and the other clips into a two prong connector. Since I didn't have a small size TC fuse I swapped the good fuse into the threaded holder and I soldered, (piggy backed) a 2.5A AGC type with pigtails onto the open TC fuse and clipped it back into the socket.

So the TC fuse indeed protected the speaker, and I'm very grateful for that. I fixed the ground problem and until I can pick up the correct fuses this will work. However I was wondering if this TC type fuse is anything special? They are two different physical sizes but how does it compare electrically with an AGC type? In theory would AGC fuses be adequate protection for these speakers? I have boxes of them.

One interesting thing I thought I'd mention was that coming right out of each speaker output on the amplifier there is a 2 amp MDX fuse that never opened. I know that the MDX is some type of time delay. Don't even know why that was in there. I would appreciate any comments on this. Thanks, Lenny

Thank you for including that page John and also the links. So I'm guessing as Phil has said that the AGC fuse will be the quickest to open, and may be somewhat of a nuisance, but will afford the circuit the highest amount of protection. I think that I can live with the occasional fuse blowing during those times I might feel like cranking the stereo up. Lenny

 

[John Robertson]

On 02/27/2015 6:26 PM, Phil Allison wrote:

captainvi...@gmail.com wrote:

I have a pair of JBL model CF120 speakers. Yesterday while listening to the system a ground wire came loose and the next thing I realized the right woofer was out. These speakers are protected by a couple of TC 2.5A fuses. One of these fuses screws into a threaded holder, (and it was open) and the other clips into a two prong connector. Since I didn't have a small size TC fuse I swapped the good fuse into the threaded holder and I soldered, (piggy backed) a 2.5A AGC type with pigtails onto the open TC fuse and clipped it back into the socket.

So the TC fuse indeed protected the speaker, and I'm very grateful for that. I fixed the ground problem and until I can pick up the correct fuses this will work. However I was wondering if this TC type fuse is anything special? They are two different physical sizes but how does it compare electrically with an AGC type? In theory would AGC fuses be adequate protection for these speakers? I have boxes of them.

One interesting thing I thought I'd mention was that coming right out of each speaker output on the amplifier there is a 2 amp MDX fuse that never opened. I know that the MDX is some type of time delay. Don't even know why that was in there. I would appreciate any comments on this. Thanks, Lenny


** JBL say the CF120 uses a 2.5 amp slo-blo fuse.

MDX are obsolete and replaced by MDL.

Lots of other options exist using T or TT fuses.

AGC is a fast type, same a F types and will bow too easily.


.... Phil

Here is a little page I wrote on fuses if anyone is interested:

https://www.flippers.com/fuses.html

Nothing on Polys though. Should update it I guess...

John :-#)#

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