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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
albertporter's avatar
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albertporter
4,949 posts
 
I don't disagree with your comments about room treatment, I invested an additional $30K for design, materials and work in my listening space when reconstruction was done a few years ago.

Even before that investment, the Isoclean fuses were enough of a change that I could have heard the improvement.

I think all this discussion is about levels of quality. I don't doubt there are many systems that would NOT benefit from a fuse swap. Most of the systems owned by guys in my audio group are the exception, and my Isoclean fuses were a nice upgrade for the $25.00 each I paid.

I have a large order of more than 20 Hi-Fi Tuning fuses sitting on my desk but waiting for my new crossover and cable to settle in before adding another variable.

As for your comment about engineers adding fuses on amps that are $5K and up, I disagree. I had a big argument with the owner of Boulder who builds some of the most expensive amps, preamps and phono stages in the world.

He doesn't even think it matters what wall plug your in, the condition of the socket or what kind of AC cord is used. A perfect example of engineer following paper rather than testing to see if there is anything to learn.

I think I'm wasting my time here. Those that believe there's a possibility of improvement with a fuse or power cord will try it. Those that are stubborn will continue to know they are "right" and never learn.

Their loss, not mine. I don't worry about such stuff, I try it and learn. If it works I support it and if it does not, I usually don't comment about it.

The reason I don't condemn things that don't work for me?

Even with my system as evolved as it is, some things will NOT work in my situation that may prove a blessing to another Audiogon member.
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rodman99999
6,206 posts
 
Albert- Don't think you are wasting your time here. Your(and Tvad's) encouragement and example of trying things for yourself is valuable. I believe there are many(perhaps a silent majority) that peruse these threads looking for tips to further their musical enjoyment. If all they could find were the negative comments of the concrete-minded, what hope would they have?
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knownothing
1,653 posts
 
I changed three of the stock fuses on my modest AMC 3050a solid state integrated amplifier to Hi Fi Tuning fuses. Performance during the "burn-in" period for the fuses was unstable and rather odd as described in the link at the bottom of this post. Now that things have settled down, I conclude that the change ultimately made a positive difference in how the amp and my overall system sounds to my ears. Although this difference was not apparent right away, the current improvement I am enjoying is of about the same order as (but different in character from) changing to higher resolution interconnects.

Answers to Kirkus' questions from my experience:

1. I am using a single 4A T slow blow fuse and two 6.3A T slow fuses Hi Fi Tuning fuses.

2. I do not have an ohmmeter.

3. The single 4A T fuse was located near the power switch. The 6.3A T fuses were used in symmetrical circuits further down the chain, one each for the left and right channels. These two replaced stock fuses that blew when I unknowingly shorted one of the speaker terminals, if that helps you. I added these three all at once and cannot separate out the relative benefits.

4. No. I blew two of the three stock fuses due to incredible stupidity, prompting me to replace all three with the Hi Fi Tuning fuses. I have had no problems whatsoever with the new silver fuses.

5. The only performance measurements I have made were of the subjective variety and described in the following post:

http://forum.audiogon.com/cgi-bin/fr.pl?ymisc&1192881548&openusid&zzKnownothing&4&5#Knownothing
warnerwh
539 posts
 
Any subject needs discussion because no one person can see every possible angle. It's necessary to know everything possible to make sure what you know or think is correct. So everybody's opinions are necessary.

Every time we all still end up at the same exact location regarding fuses, cables and power cords. I'm as guilty as everybody else too by contributing to one of these discussions. Think I'll go listen to some music.
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