There is no measurable difference with a magic $300 audio fuse and a $0.30 fuse, with the exception of wound slow-blow/delay fuses, these introduce less noise. Also, glass cartridge fuses also introduce less noise.
There is one measurable problem though, and that comes with age. The fuse clips and cartridge ends will become corroded over time and will introduce THD. Even a small unseeable amount of corrosion can have a measurable result. I build my own equipment, so it is around for a long time, because, well, it's just so damned good! There are a couple of things that I do to help.
There is one thing I want to try, but I'd like opinions first. I would like to gold plate the clips and fuse ends, perhaps with “Immersion or Autocatalytic Gold Plating”. I think you can see the problem with standard electrolytic plating a fuse! I could also plate a few other corrosion problemsome parts while I'm at it, so I won't have to hunt down (by then) obsolete replacement parts. Silver plating may also be a more cost effective solution, it doesn't corrode too easily and the corrosion tends to be conductive (but I don't know how conductive).
Any thoughts?
There is one measurable problem though, and that comes with age. The fuse clips and cartridge ends will become corroded over time and will introduce THD. Even a small unseeable amount of corrosion can have a measurable result. I build my own equipment, so it is around for a long time, because, well, it's just so damned good! There are a couple of things that I do to help.
- I squeeze the clips a little so they have a tighter grip on the fuse cartridge.
- I put Krazy Glue along the joint where the glass cartridge meets the conductive cap ends (carefully so I don't get glue on the sides of the cap ends). I have seen fuses with visible condensation on the inside of the cartridge, the glue takes care of that.
There is one thing I want to try, but I'd like opinions first. I would like to gold plate the clips and fuse ends, perhaps with “Immersion or Autocatalytic Gold Plating”. I think you can see the problem with standard electrolytic plating a fuse! I could also plate a few other corrosion problemsome parts while I'm at it, so I won't have to hunt down (by then) obsolete replacement parts. Silver plating may also be a more cost effective solution, it doesn't corrode too easily and the corrosion tends to be conductive (but I don't know how conductive).
Any thoughts?
Hello,
Gold plating would be nice. I have used contact cleaner on both the fuse and holder and then contact enhancer on both before putting them together. Have never had any sign of corrosion of oxidation. FWIW.
(Craig contact treatments - bottle goes a long way.)
Gold plating would be nice. I have used contact cleaner on both the fuse and holder and then contact enhancer on both before putting them together. Have never had any sign of corrosion of oxidation. FWIW.
(Craig contact treatments - bottle goes a long way.)
Nice to know, I'll wait a while and see what the consensus is rather than wait 20 years to find out how effective it is! (contact cleaner) maybe in combination with a lubricant of some kind, just to be certain. Besides, I'm getting old, who knows if I'll be alive in another 20 years! I need to be granted another few hundred years of life so I can experiment some more! Maybe I should experiment with the fuses on my favorite non-self made audio amplifier, a Yamaha P2100 or was it a P2200! A great amplifier if you change out the main filter capacitors, add an inrush and drain circuit. Add true balanced XLR to single ended circuits, and change out a bunch of crappy parts on the main boards! They just didn't have the technology for some of those good parts back then, but the design is excellent! The inrush was so a severe that the lights would dim when you turned it on! It has massive filter caps and it's 220WRMS in to 8Ω! per channel. The main voltage is 100V and is taped at 12V for utility voltages. The transformer is a huge shielded torrid transformer, impressive for way back then! It has a heavy duty toggle switch. a power on indicator LED, and individual attenuators for volume control. Nice and simple! As you can tell, I love that old amplifier! I think it was made in 1977!
Thanks.
Thanks.
Last edited:
Sorry, I don't have any measurements handy, I didn't think I'd need them, I'm just designing a beast of a power supply at the moment and started to think about it. I first read about it in a simple MOSFET audio amplifier design I believe. Once again sorry, it's not nice to make claims without verification!
Last edited:
A thin smear of automotive dielectric grease on the exposed parts of the fuse's metal will do wonders to prevent corrosion over time. Ensure that the fuse is tightly clipped in is socket/clips and it will do no harm.
Maybe its worth delaying this thread until the forum has some time to view and respond to those measurements? I mean it would be sad to think that this was just snake-oil type commenting, or the result of poor amp design, or poor part selection from the amp manufacturer, or the result of such a poor operating environment that anything and everything will corrode given time, or that basic contact protection such as a smear of vaseline or dielectric grease would have maintained normal working conditions for decades.
I appreciate that fuses carrying high currents, and that have substantial self-heating, and live in a humid and slightly corrosive environment (eg. electroplating shops) do need fuse contact maintenance using a very light smear of appropriate grease to avoid contact area pitting and loss of contact.
But that is I think a world apart from wanting to deploy additional fuse cap plating, given that a standard glass body miniature cartridge (5x20, 3AG style) complies to IEC or UL standards and is made by a reputable manufacturer that identifies that they are using reasonably plated end caps (brass alloy with nickel plating and whatever else is commonly used for corrosion prevention) and has passed high operating temperature, high humidity and salt-spray standards testing. With the same going for the fuse holder terminals. There are also fuse models fairly commonly available that have end caps with leads, so as to avoid fuse/terminal contacts.
I should note I do have a small pot of deoxit and do clean connectors and fuses with it when I rebuild things. And the Deoxit has been useful on tarnished contacts (usually car remotes that stop working). And worth tightening fuse holders and checking that the sort you are using has a good contact area as some only touch in a line on each side.
One difference, we don't know that the expensive fuse will blow at the rated current and time factor.
Another difference, the expensive fuse may not have a UL or other safety rating.
Do you have any support for these statements?
I've been giving testing a lot of thought and decided that though a full scientific analysis would be the best, however, the number of tests required would be expensive, and money is something I don't have much of anymore! It would also be very time consuming, and I also don't have access to an R&D department anymore, I have a very well stocked home shop though, so I'm happy with some of the common sense advice I have received, and thank you for them, sometimes the simplest things are the easiest to overlook!
One thing that was mentioned was possible problems with heat at high currents, I never considered this before because I never encountered the problem before, but would either a larger case size like an AGY or AGU (I usually use 5x20 or 5x15) dissipate heat better, because high temperature fuses are expensive! Fuses are an entire and complex field all on their own (I've been studying them some), so I will go with a general use approach such using contact cleaner and contact enhancer and using a die-electric grease approach. I'm wondering about military grade leaded fuses at the moment, they're not too expensive for a non-production use.
If there are any more ideas, they would be appreciated!
Thanks everyone!
One thing that was mentioned was possible problems with heat at high currents, I never considered this before because I never encountered the problem before, but would either a larger case size like an AGY or AGU (I usually use 5x20 or 5x15) dissipate heat better, because high temperature fuses are expensive! Fuses are an entire and complex field all on their own (I've been studying them some), so I will go with a general use approach such using contact cleaner and contact enhancer and using a die-electric grease approach. I'm wondering about military grade leaded fuses at the moment, they're not too expensive for a non-production use.
If there are any more ideas, they would be appreciated!
Thanks everyone!
How do you choose a fuse value, and characteristic, and manufacturer, to suit an amp? Are you applying such fuses for mains AC primary side, or power transformer secondary side protection or ?
I'm not too worried about the manufacturer, as long as it's from a reputable source (not someone who may be carrying knock-offs) and is not known for poor quality fuses. I seldom need to buy fuses because I have a few hundred of different values and types and manufacturers in stock (as I said, I have a well stocked home shop), I tend to fuse both lines on both primaries and secondaries (I don't want to replace a $400 transformer) and sometimes at the output, especially in high power regulated supplies where a pass transistor(s) is used. The values are voltage and current dependent of course, and the type is dependent on the application. Components that can handle short duration high peaks can have a lower current rating and be delay blow and so on, just textbook usage, nothing fancy.
Does that mean you measure the operating currents on primary and secondary side using a suitable true rms meter with high crest factor and choose a fuse current rating from that?
Do you use 250VAC UL284-14 or IEC60127-2 compliant fuses, as they have different continuous current capability for the same rating? Do you check that the fuses you use are correctly labelled and related to a specific manufacturer part number, as fuses tend to get purchased or sourced and then put in a common bin and their providence lost very easily?
Do you use 250VAC UL284-14 or IEC60127-2 compliant fuses, as they have different continuous current capability for the same rating? Do you check that the fuses you use are correctly labelled and related to a specific manufacturer part number, as fuses tend to get purchased or sourced and then put in a common bin and their providence lost very easily?
I wasn't aware of a labeling problem, is this an issue with companies like LittleFuse and Bussmann and Eaton. it's mostly what I have in stock. They are the primary companies I buy from, and I buy large quantities directly and smaller amounts from Mouser and DigiKey. Anyway, my calculations haven't been a problem, they only blow because of a part malfunction, which never happens, I don't buy cheap Chinese crap. I use good capacitor charge surge protection circuits and good external surge protection circuits. The only problem is with corrosion after long periods of time (15-20 years), normally I wouldn't be concerned about this, but I doubt I'll live another 20 years, and though I have very well documented projects, trying to find someone to repair electronics is becoming more and more difficult unless you speak Chinese, and you don'e want them to touch a good circuit! (my apologies to the people of China, but for quality electronics, you have a long way to go!) I'd hate to think that whomever I leave my projects to will end up throwing them away because of a simple fuse! I've been working on my current computer interfaced audio system for 2 years now! It's almost finished. It's a lot of work and time and money to just throw away!
It's interesting to appreciate that you seem to buy a fuse from its current rating, fast or time-delay characteristic, and manufacturer credibility. And that you don't measure the current through a fuse as part of it design selection.
I'm guessing the secondary side winding fuse calculations relate to summing up the max operating current through the various stages, and maybe you then translate that back to an ac winding current, and then select a UL218-14 fuse current rating that is the next size increment back from 80% of the fuse rating? Do you then just use a time-delay/slow-blow type to cover in-rush if you are going in to a high in-rush filter, or do you use a simulation package, or ?
I'm guessing the secondary side winding fuse calculations relate to summing up the max operating current through the various stages, and maybe you then translate that back to an ac winding current, and then select a UL218-14 fuse current rating that is the next size increment back from 80% of the fuse rating? Do you then just use a time-delay/slow-blow type to cover in-rush if you are going in to a high in-rush filter, or do you use a simulation package, or ?
- Status
- Not open for further replies.