2. misc-audio
  3. 166294-93199

Is it safe to use a higher amperage rating fuse?

Today was my 2nd attempt at trying out Synergistic Research fuses.  About 3 years ago when I had separates, including mono block amps, I bought a set of Blue fuses.  One component had a mfg spec of 250mA and the retailer said go with 315mA.  My two mono block amps each had a 6.3A.  When I installed them one of them blew upon powering up.  The retailer said we should go up to the next rating.  I was a bit frustrated at the experience and didn't feel comfortable putting higher values in my expensive components.  I felt these expensive fuses should be made to tighter tolerances than the cheap BUSS fuses I had been using.  If I remember correctly, that was the actual argument that the dealer told me.  They are mfg to tighter tolerances so a 5A SR fuse was almost dead-on 5A while a cheap fuse may actually be 5.3A or whatever.  This also was a bit confusing at the time so I sent them all back.

Okay...3 years have passed and now I have a single integrated amp which has a 5A fuse.  Much less to invest in the upgrade so I ordered an Orange.  It came in today...installed....pressed power...on and off went the amp.  DAMN!!  I contacted the retailer and SR on the same email.  This was a different dealer from 3 years ago.  The retailer said I should go to the next value up.  I said no and and they are waiting for the tracking info of my return shipment.

I did a quick search of my question before posting and saw a thread about the Red fuses and someone said they had to do the exact same thing.  Is everyone putting higher rated fuses in their gear that is worth thousands of dollars?  Is there no risk in this?  I admit that I don't know what could actually happen from that.  It seems that other things could burn up if a higher amperage fuse is in place.  I am compelled to simply stick to the mfg specs for something that I don't understand because I don't want to create problems just from a simple tweak.

Should I let them ship me a 6.3A or just be done with this?
dhite71
auxinput
2,920 posts
 
Littellfuse makes a 285 series in the small 5x20mm size that twoleftears is talking about.  It is available in either gold-plated or rhodium-plated end caps.  The problem is availability.  Both Digikey and Mouser have them in the catalog, but only actually have very limited sizes in stock.

Digikey stock:
https://www.digikey.com/catalog/en/partgroup/285-series/76506

Mouser Stock:
https://www.mouser.com/Circuit-Protection/Fuses/Cartridge-Fuses/285-Series/_/N-ba8h0Z1yzvvqx?P=1yzv7...

Digikey has a rhodium-plated 5A version.  Mouser has the gold-plated 5A version.
dhite71 OP
331 posts
 
@auxinput     I did get the correct SLOW blow fuse so this was not the issue.  I value what the MFG recommends.  They advised me to never put a larger value fuse in any component as this is how the safety features are designed.  Seems some of us are finding no issue with that strategy but I am not comfortable to roll the dice with my gear.  
pauly
1,012 posts
 
Try slow blow fuses.

If a fuse blows when you power up you either have a short which means no matter what value fuse value you try it will do it's job and blow, or the transformers allows an inrush of current which temporarily exceeds the current rating of the fuse. Slow blow fuses are made to deal with this issue. 

Have a look and see in the OEM fuses are slow blow fuses - they probably are. 

Do not exceed the manufacturers recommended rating on the fuse no matter what the armchair electrical engineers say. They've obviously never designed electrical equipment or even owned a soldering iron,  and they will most certainly not cover the cost of expensive repairs should something go awry. 
pauly
1,012 posts
 
"  I value what the MFG recommends. They advised me to never put a larger value fuse in any component as this is how the safety features are designed. Seems some of us are finding no issue with that strategy but I am not comfortable to roll the dice with my gear.  "

I tend to agree with your sentiment. 

Do a sanity check. Get a couple of manufacturer rated regular (i.e. "non-audiophile") fuses and try them. If they don't blow and your audiophile fuses blow, the fuses are at fault and send them back.

If you blow the regular non audiophile fuses that are rated per your manufacturer specifications, you need to contact your manufacturer. 

dhite71 OP
331 posts
 
@pauly no issues otherwise(knock knock).  This was simply a tweak/experiment.  The stock 5A fuse works as expected.
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