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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
lacee
811 posts
 
I am left to wonder what brand of upgraded fuses did you have the problems with?

Blowing fuses could mean several things- a problem with the amp(unlikely as the original stock fuses didn't blow) or that the wrong value of fuse was used or the fuses were defective.

I once blew a couple of expensive HiFi Supremes when I mistook the .5 amp for the 5 amp.

In my case, the sound was worse when I went back to the old stock fuses,my spares.
All was good again with the replaced upgraded fuses,of the right value in the right location.

The amps are Acoustat servo tube amps which take a .5 amp and a 5 amp fuse in each amp.

If you suspect the fuses were sub standard, send them back,maybe the company will replace them.

At least let us know what brand they were.
Maybe others have had similar bad experiences with them.

I've used AMR, Iso Clean,and HiFi Supreme,no problems with the fuses,just my bad eyesight.
branislav
405 posts
 
"I once blew a couple of expensive HiFi Supremes when I mistook the .5 amp for the 5 amp."

That's why in Europe .5 is written as 0.5.
lacee
811 posts
 
At least I can say that the fuses did the job they were intended to do, they will blow if used in the wrong application.
Some folks have expressed concern that they may be too robust and not "fail" when called upon to self destruct and save the gear.

My problem was that I was new to my Acoustat amps and the stock .5amp fuse looked to be the more robust fuse, with a thicker filiment and spring like make up, the other fuse was a simple thin thread for a filament.

There were no markings on the amp to designate what value of fuse on either of the two fuse holders.

So what I thought was the 5 amp fuse( the thick spring stock fuse) was actually the .5amp fuse.

Of course the 5 amp fuses were OK,and no damage was done when they were in the .5 amp fuse holders.
But the .5 just went pop,and no damage to the amps , just the wallet and my pride.
Post removed 
jburidan
803 posts
 
I think Elizabeth may be right in saying that aftermarket fuses are amped-up. That would explain the sound. At any rate, I'm not risking it in my precious kit.
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