I suspect the 7A fuse has such low normal resistance it is not a worry in a 110 W amplifier. However I find rail fuses a bad idea. One tends to blow guaranteeing DC into the load. Since there is no correction to the output from the rail with the blown fuse, the primary may not fail!
So I am a big fan of properly sized mains fuses and dealing with the effects of the dynamically sagging mains by using adequate filtering or regulation on the input control side and allowing that to keep the output stable even with a bit of mains sag. I don't really expect an audio power amplifier to clip playing recorded music in a proper setup.
Nice prose, and as usual a graph without the slightest indication on how it was determined, what's represented, you know, those little pesky details (BTW, I see 5x peaks only, but then I have no idea what I am looking at).
Ok, I'll give you, higher voltage fuses have a higher resistance, 0.26ohm for 1.25A.
Claiming that a fuse that doesn't blow can drop 12% of an 100W audio power amplifier is utterly nonsense, whatever way you try to dress it up, unless it's one of those pathological designs that you love so much to talk about. 12%, perhaps true for a 100kW electrical welding machine.
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Ah the trolling.
What do you think the average current shown is? You could even go back to when that data set was first presented in this thread and read the discussion.
Let me know when you measure an audio power amplifier and the AC line power compression what you get. 1 dB is actually quite good for many commercial products. Many are worse and the well designed high end products better sometimes!
All you have to do is run a sine wave into the amplifier under load and increase the level. Just watch the input output voltage tracking as you approach peak power. Compression of 3dB is not unknown.
Ah, the trolling: deflecting discussion, introducing false targets, etc... sounds familiar.
I'll wait until you explain how a non pathologically designed 100W audio power amplifier can lose 12% of the output power due to the fuse alone. Meantime, this is utterly BS.
Bill,
Just think when you get a powerful enough sound system, a free light show!
Around here at home the daily deviation is much less. At home the AC power line mains voltage stays within 1/2 volt RMS AC except in the summer. One neighbor on the same distribution transformer doesn't believe in using an effcient air conditioner. I think his current draw must exceed 75 amps at 240 volts! Normal for a house that size might be as high as 20 amps. So the dip hits almost a full volt.
Or you can't produce any arithmetic that make sense. The one above doesn't.
None, why bother? Scenario of blowing mains fuse is usually the amp is farkled anyway so let the smoke settle and fix it. The only fuse short I ever regretted was in a multimeter where the current sense resistor subsequently smoked.
Good, now you know assumption can be twisted, including your own. Seems that you are not in command of sufficient intelligence to be a mole, but there still is a possibility of acting. If you are not a mole stop creating situations resulting in discomfort of other members, and I do not include those your posts are addressed to. If you are or becoming one, it is just a matter of time for the mods to kick you out.
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If I'm following you the suggestion is that the line voltage can drop to 84V when the amp is under full load? I think I must be oversimplifying something here. Many newer amps would shut down under those conditions (switching supply undervoltage protection). Are you talking peak or RMS measurement? I find RMS measurement to be very misleading on AC supplying any rectified load. 1-3% THD is common with all the rectified loads today. Most switching supplies and any current amp sold into europe will need power factor correction which should reduce the peak clipping.
If you are talking a difference in gain in the amp as you approach clipping that has been a "feature" for some consumer amps for 30+ years and is intentional.
I have measured high peak currents (150A) on amp turn on but never anything like 10A peak in operation for a realistic domestic amp. The max continuous current for a product connected to a 120V 15A circuit is 12A. If you are drawing 4:1 peak to average the thermal time constant of the fuse will respond to the rms current unless its a fast blow which would already have vaporized.
My biggest concern about tuning fuses is if they are actually safe. Are they UL approved? What is the peak interrupting current? Is there a published curve? Are you prepared to deal with the fire inspectors trying to not pay your insurance claim?
In years past it was accepted to include the output fuse inside the feedback loop. That can make a difference.
Scott, it's obviously a matter of reducing the risk of possible fire initiation.
Also Rule 3, note 2
diyAudio Rules
George
Is there an approved commercial component that works like this. That would substitute your ordinary glass fuse in an amplifier? It would take more space, but still?
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