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#1
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Input (MAINS) AC Fuse
I've NEVER had to replace an input AC fuse on a piece of stereo gear,
but my old Kenwood KA-9X amp blew one the other day. It's a Toyo 6A fuse (thats ALL it says on it..both ends: Toyo 6A) , and I suppose a 250VAC/6A fuse would work except I can't tell if it was a slo-blow or fast blow cause there isn't much left. I'm surmising its a slo-blow, but can anyone tell me what type is typically used for the input fuse on solid state integrated stereo amps. |
#2
Posted to rec.audio.high-end
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Input (MAINS) AC Fuse
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#3
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Input (MAINS) AC Fuse
Start with a regular fuse and if it doesn't blow then you are probably fine.
If it does then try a slo-blow. Slo-blow are usually for equipment that has high startup draw like motors. Because it delays you do not want to use one unless you need to. wrote in message ... I've NEVER had to replace an input AC fuse on a piece of stereo gear, but my old Kenwood KA-9X amp blew one the other day. It's a Toyo 6A fuse (thats ALL it says on it..both ends: Toyo 6A) , and I suppose a 250VAC/6A fuse would work except I can't tell if it was a slo-blow or fast blow cause there isn't much left. I'm surmising its a slo-blow, but can anyone tell me what type is typically used for the input fuse on solid state integrated stereo amps. |
#4
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Input (MAINS) AC Fuse
On May 6, 6:57*pm, wrote:
I've NEVER had to replace an input AC fuse on a piece of stereo gear, but my old Kenwood KA-9X amp blew one the other day. It's a Toyo 6A fuse (thats ALL it says on it..both ends: Toyo 6A) , and I suppose a 250VAC/6A fuse would work except I can't tell if it was a slo-blow or fast blow cause there isn't much left. I'm surmising its a slo-blow, but can anyone tell me what type is typically used for the input fuse on solid state integrated stereo amps. Slow Blow fuses will leave the ceramic rod inside the holder. Dual-Element fuses will leave the small spring and clip inside the holder. Standard & Fast-Blow fuses will leave little or nothing remaining inside the holder. 6A seems mighty close for a 700-watt @ 120V (5.8A) integrated amplifier. What does it say on the fuse-holder? Mostly these things typically use a dual-element or slow-blow as well. IF the fuse blew because it is a 6A standard fuse, go ahead and replace it with a dual- element and see what gives. If it blew for some other reason -beware. But, before you willy-nilly replace the fuse and go back to sleep, you need to do several things: a) determine to the degree possible _why_ the fuse blew. Anything unusual happen? You may just be very lucky that a 6A standard fuse held for so long anyway. b) determine what the correct fuse should be. Look up a manual or service literature or look at the fuse-holder for information. Note that a fuse at 120V will carry twice the amperage rating than a fuse at 240V for the same unit - not knowing where in the world you might be. So, 6A at 240V is "too many". 6A at 120V is "barely enough" if a standard type. c) if you cannot do this, determine the actual current required by the amplifier. You can do this to a degree by connecting it to a sensitive ammeter and running it hard, or you can intuit from the nameplate rating (in watts) to a reasonable degree. 700/120 = 5.83A, use 6A (Dual-Element). Note that the turn-on surge may be up to 3X the steady-state requirement - and perhaps why it is that 6A fuse blew - all the previous owner had was a standard fuse, and 6A was large enough to handle the turn-on surge for a while. Dual-Element fuses: Why do I harp? A DE Fuse acts like a slow-blow at turn-on, handling the surge, but acts as a standard fuse after the initial surge. So you get maximum protection of the equipment with little risk of overloading. Note that a Slow-Blow fuse operates on a function of overload/time. A small overload will be tolerated for a very long time, a large overload for a much shorter time. That small overload may be tolerated long enough to cause "other" parts to fail. A dual-element fuse will tolerate a large load for a brief period, but then fails at the set-point. Slow-Blow fuses (wire wound around a ceramic core) protect nothing well. Peter Wieck Melrose Park, PA |
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