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Hi-Fi Fuses - SNAKE OIL? - or something in it?

There's a lot of chatter about the benefits of those high prices gold plated fuses with silver conductor etc. etc. all over the web and the consensus ranges from FANTASTIC!!! to much more subtle observations.

It makes sense to me, epseically in light of spending lots of $$$ on good power cables, that having a skinny piece of aluminum conductor in a glass tube (i.e. a cheap fuse), in the power loop would be detrimental to the performance of the components.

I decided to revamp my DIY power supply I'd built for the Cambridge Audio 640p phono stage and DACmagic in order to test this out - and since it's a DIY project there is no UL Certification to void.

First, I bypassed the fuse link completely to confirm there would be an improvement and give me the best benchmark to compare against - YEP - BIG DIFFERENCE - much more this, that and the other :-)

So then I started looking for hi-fi fuses - WOW!!! - talk about pricey.

Two fuses for the power supply was going to cost $120+ AND I thought I'd probably have to buy a better quality fuse block to make the most of those fuses.

Then a moment of enlightenment - most power supplies and conditioners are protected by pushbutton breakers and not fuses.

I found breakers of the required current rating and installed them into the power supply. I imediately noticed that there was no deteriation in fidelity when compared to the same unit with the fuse link bypassed - GREAT!.

On reflection, the fuses I had in place were rated at 3 amps - so they use a pretty thin fuse wire in them. If I had used a fuse of a higher rating, i.e. it uses a thicker conductor, then I believe that there would be less of a difference between the fused and bypassed implementations

SO - do the expensive fuses work?

Well the empirical evidence out there would suggest they do
- I do know the cheap fuses are not good!

I know bypassing them does improve the sound - a lot in my case
- BUT THAT'S NOT SAFE FOR ONGOING USE

I know breakers work as good as bypassing the fuse
- BUT MESSING WITH A POWER SUPPLY VOIDS UL CERTIFICATION - NOT GOOD!
- FYI a couple of licensed technicians I know WILL NOT change the design of a power supply at all.

I believe the amount of benefit is related to the fuse rating
- but don't go replacing 3 amp fuses with a 20 amp fuse - that's not safe either.

Whilst looking for fuses I discovered AMR Gold fuses priced at $20/fuse.

Now that's definately more affordable than most others at 3-4 times their price.

One supplier I know of in the US is Avatar Aacoustics

If you have had experience with quality fuses please share - especially if they are "modestly priced" i.e. $20-$30 per fuse. And please provide a source :-)

Also, can anypne confirm that Slow blow fuses are better than regular?

And Remember - IF YOU AIN'T LICENCED - GET A TECHNICIAN!

Many Thanks
williewonka
isochronism
2,893 posts
 
Your chair resents that.... but yet, it puts up with your stinky butt all these years? Sorry, Mapman. I couldn't resist, no offense. HA
mapman's avatar
mapman
22,198 posts
 
"Your chair resents that.... but yet, it puts up with your stinky butt all these years?"

Chairs deserve more credit......
isochronism
2,893 posts
 
I agree. Chair possess much fortitude!!
mitch2
3,969 posts
 
Most manufacturers I have spoken with not only don't buy into the audio-specific fuse thing, they advise against it because of questionable ratings and quality.
Last year, I spoke with the head service guy at one of the largest component manufacturers in the US and he said their company was continuing to discuss how to address aftermarket fuses and the effect on warranty, but their current position was that the use of an aftermarket fuse would void the warranty in the event of damage of a questionable nature (that should have been prevented by the stock fuse).
I do know one manufacturer/upgrader who recommends audio fuses in their products but they actually go a half amp higher than with regular fuses because they suspect the audio fuse they use is underrated (because the component kept blowing those fuses until they upped the amperage).
I used to use HiFi Tuning fuses, back when I tried things "just in case" they would make a difference, but I haven't heard a difference compared to stock fuses and I don't worry about fuses and other "last one percent" stuff much anymore.
One thing I would be careful of is bumping fuses up one amp as recommended earlier in this thread. Depending on the rating of the fuse being replaced, a 1A increase could be significant and in general, IMO you are taking a chance on both warranty and protection of your gear when you deviate from the manufacturer's rating.
brownsfan
1,508 posts
 
Mitch2, as usual, you post is well reasoned. It is my practice to do nothing to a piece still under warranty. The risk benefit equation just doesn't favor tweaking in that instance. With respect to replacement fuses, it has been my experience that the only place they made a huge difference was in my Magneplanars. It makes sense that one might hear a more pronounced benefit there. Improvements in other applications have been audible but more subtle. Enough to warrant spending the relatively low cost of most fuses, but not the same order of magnitude as the improvements one can obtain with a change in cables for instance.

I think people need to be realistic in their expectations and think about cost-benefit and risk-benefit. Would I spend $100 to replace the mains fuse in my Cary's? Yes. Would I spend $1000 to replace the rest of the fuses in the Carys? No.

As far as messing with the ratings, I have used a lower rated fuse, but I would never use a higher rated fuse. If a replacement fuse of the correct rating continues to blow, I would probably just go back to stock.
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