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Fuses

I’ve read of views on whether amp fuses impart any sound quality or coloring. I had a recent experience that has made me re-think my views (fuses do not affect sound) and wondered if others had a similar experience. 
I have a Line Magnetic integrated amp. After heavy regular use for over 5 years, one day it just wouldn’t power up. After checking the power supply, I assumed it must be a blown fuse. I recalled that Line Magnetic sent with the amp two replacement fuses of the same type/quality that was pre-installed. I dug out one of them from storage, replaced the fuse and the amp powered up normally. 

What surprised and delighted me was the change in sound with the replacement fuse. Fuller bass, more detail and more warmth. I have rolled the tubes several times in the amp, and am attuned to the subtle changes that can make. Popping in a fresh fuse seems to have had a similar affect. And these appear to be cheap fuses, available for a few dollars at most. I don’t think I understand any of this. 
bmcbrad
yuviarora's avatar
yuviarora
537 posts
 
I work in industrial Automation (or used to).
I also have a ton of experience working on Audio equipment, and my comment about the fuse blowing up was just a silly attempt at forum humor.
I can build/repair anything.... so not really worried about that.
Having said that, I have kept the fuse at the lower end of my required rating, and I might have played it a little too safe. My next prototype will be a thicker filament.
The fuse rating of copper that I am using as a template is in open air, the ceramic fuse cylinder also acts as a heat trap. .
It’ll be interesting to see if it sounds different than the one I have already made.

noske
783 posts
 
OK, thankyou, I'm glad that its clarified that you are very experienced.  I think that is important.

The ceramic build having heat trap protection, that's interesting.  Is this good?  My lay intuition suggests that it might be good if any heat was dissipated.  Obviously not.

Anyway, on the ACME site they say that ceramic may be inappropriate for amps that do not have inrush protection, or the fuse may be "destroyed".   How do you know if an amp (solid state) has inrush protection?  ACME suggest using a stock (Littelfuse?  they don't say) ceramic fuse first and just wait and see....if it is destroyed?

https://www.revolutionpower.com/acme-audio-labs-large-silver-ceramic-fuse-cryogenic-treated

I am not going to pretend that this strikes me as particularly robust advice coming from a manufacturer of premium fuses for use in quite expensive equipment..
yuviarora's avatar
yuviarora
537 posts
 
@noske  Most Solid state amps have inrush protection, it is tube amps that you have to usually worry about, and that is why people use slowblow fuses for them.
If a ceramic fuse blows on your solid state amp, it  won't damage the amplifier, you  would just have to go a size up and test it out to get to the required functional rating. 

noske
783 posts
 
@yuviarora

Thanks, OK, that's good to know, very good and comforting general advice.  (anecdote - my SS amp manual is inconsistent anyway  - on one page it says 1.5A, on another page 2A.  I use 2A.)

Yes, I had kinda guessed that about amps with glass, as my tube amp has the slowblow fuse as part of the IEC socket enclosure before any possibility of it being able to be manipulated by anything.




fiesta75
1,378 posts
 
My vote goes to George for electronics. MC makes some simple mistakes like series and parallel resistors... The best fuse is no fuse, agreed. Instantaneous CB unless your trying to protect your multimeter...
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