2. amps-preamps
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New Fuse Thread . . .

So the talk about the sonic effects of fuses got way out of hand, and I would like to know some details from those who have actually tried the boutique audio fuses. So if you have, please let us know any of the following:

1. What value (ampere rating) were you using, and was it fast or slow-blow (time delay)? Time-delay fuses usually have a letter 'T' in their rating, like "T2.5A" is a 2.5 ampere, slow-blow fuse.

2. Does anybody have a reasonably decent ohmmeter, and could you measure the difference in resistance between the boutique fuse and the standard one? If you measure, be sure to subtract the resistance of your test leads. Of course, if somebody has an impedance analyzer, I'd love to see that data . . .

3. What position is this used in? That is, on the AC line, or after the transformer, after the rectifier, etc.?

4. Has anybody had occasional fuse-blowing with the stock fuse, and replaced it with a boutique fuse, and had the boutique fuse blow? Did the failure patterns seem similar to both types?

5. Has anybody made any performance measurements on their equipment with various types of fuses?

So I'm hypothesizing about some ways in which fuses could affect circuit performance, and there are two things I can think of. First, if silver wire is used, then since silver has a lower melting point than copper, the fuse resistance *could* possibly be lower for a given rating. Also, many slow-blow fuses seem to have a resistive element wound around a central core, so it's possible that these could be inductive as well. So what could that mean in a circuit?

First, for a slow-blow line-fuse application, where there is an AC input filter, adding/changing resistance/reactance in the AC line could affect the Q of the input filter, and if this unit was RF suceptible or had a switch-mode power supply, the fuse could therefore affect RF emisions or suceptibility.

Second, many power amplifiers have no snubber capacitors on their rectifiers, and also use fuses for the power-transformer secondary. It's possible here that changing the reactive/resistive characteristics of the fuse could slightly change the switching speed of the rectifier diodes, and affect the diodes' RF emissions.

Third, some power amplifiers use fuses on the DC rails, after the filter capacitors. In this case, it's easy to see how fuse resistance could influence the amplifier performance.

Fourth, if a fuse was placed between a low-voltage linear regulator (like the ubiquitous 78XX or LM317) and its local input filter capacitor, the characteristics of the fuse could affect the regulator's stability, and cause it to oscillate.

And finally, there's the UL rating issue . . . it's important to have confidence that a fuse will blow when its supposed to, and without any certifications, who's to say? At $40 a pop [sic], testing their tolerance and production consistency is a very expensive proposition indeed.

Now I'm not claiming that fuses make a difference, or don't make a difference, I honestly haven't tried, and I'm too cheap to conduct an exhaustive study into the matter. But if anybody has some good data (even if incomplete) on their experiments, please share it.
kirkus
theaudiotweak
2,774 posts
 
4life,
I have an in house design for an audiophile grade breaker box.The weak link has been the crappy breakers themselves. I could modify the design to house the breaker/fuse modules you reference so as the choice in finish of the fuse could be changed out by the end user to suit their flavor of the week. Tom
theaudiotweak
2,774 posts
 
4life,
Got me going here. If you have available there in Germany try out some AVM on the fuses for the modules you describe in use. Tbg and I have both tried fuses or magnets unpainted and then painted with this blue magic coating, I'm sure many others have as well. Be nice to hear your feedback on AVM's application at the source/breaker. Besides it may help me confirm a mechanical grounding method. More better music with AVM than without. Tom
audioquest4life
727 posts
 
Tom,

The AHP breakers allow one to experiment with either the gold plated cooper or silver fuses. I have settled on the copper fuses for the main circuit driving my amps, while the rest of the equipment on another fuse block is using a silver fuse. The fuse block on the panel in Germany is easy to get to and allows for quick changes in the fuses if I want to play around or need to replace a blown fuse in the circuit breaker. I would suggest if you can adapt the german style breakers do it, they are so easy to install here, I watched the electrician do one install in about 2 minutes. You will need about a space and a half to fit the wider fuse block though, and they are more rigid and heavy duty then the "stock" fuse blocks (breakers). I ran 3 x 2.5mm heavy duty wire from the circuit to the wall outlets regular heay duty copper wiring, however each line is isolated from each other in their own pipe in the concrete wall. Since the walls were made in some other place and dropped in, I could have opted for any mod in the walls I wanted.

When we built our house of course electrical planning to include isolated conduits in the concrete walls was part of the plan. I opted for 5 dedicated circuits all with the AHP fuse blocks as they are more rugged, provided me with more wattage capability then the stock fuses and of course to be able to experiment with designer fuses.

I have never heard of AVM and the benefits it is supposed to provide. Could you please elaborate. Is it similar to the silver coating we can get from Walker Audio? I am not sure I would want to experiment that much, especially in the circuit panel. What have you noticed in regards to changes in musicality or noise floor. I may be tempted if you could provide some more information. Thanks.

V/r
Audioquest4life
theaudiotweak
2,774 posts
 
4life,

Many good thoughts going on here, thats great. Norm/Tbg probably has the most insight and backround with the AVM product so I hope he will join in here. AVM is short for Anti-Vibrational Magic. My use has been on things I don't want to resonate such as transport components..and cd coupler, drawer, sliders, supports etc as well as electonic components themselves. Wherever I have used this product it has lowered the virtual noise floor allowing for more musical detail to be evident. The noise floor is again reduced when applied to the non conductive contact area of a fuse.

The flow of those electrons must generate a noise path where ever they travel. Or perhaps AVM in some way is acting as an RF shield of some sort. AVM is a thick though paintable and drys to a very hard blue color. The magic is that all the music passes, without the haze of resonance in trace. Its not a contact or surface enhancer nor is it a soft goop that slows and damps the flow of energy.

With your description of fuse placement in the modules it may be easy for you to remove the fuse quickly and easily and be able to paint the non conductive contact area of the fuse with AVM. I usually use a ceramic heater or blow dryer to speed up the drying time. Its great to take as much control of the electrons as soon as the service company dumps them into your room. Tom
tbg
5,263 posts
 
I first heard of AVM about a year and a half ago. I ran into a company using it at the 2007 RMAF, Reference 3A which used it in their Grand Veenas. It is a Canadian company that sells hundreds of liters of it monthly to Asian manufacturers. Only one principle there is at all interested in end users.

I have been using it since that time and found it strikingly effective. Many are initially skeptical about it, but not for long. It definitely is not just acoustic dampening but has electrical influences. It is wonderful on input, output, and electrical wires and on transformers. I have painted the insides of pcs and even in one case the entire pc under the sieving. I have painted the inside of wall outlets, and I have painted cds. In the latter case FIM's new Ultimate Discs have AVM spray painted on them.

This is not an easy tweak to use as it might adversely affect your resale value. It received a Product of the Year Award from Enjoy the Music.
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