Amp fuses - quick question

Discussion in 'Amps and Cabs' started by zep41, Sep 10, 2008.

  1. zep41

    zep41 Member

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    I was doing some work on a 1964 Fender Champ and it needed a new fuse.

    The amp requires a 1 amp slow blow fuse (written on the back of the chasis) so I went up to Radio Shack and purchsed a few 1 amp slow blow fuses. Well, they turned out to be WAY too small for the fuseholder in this particular amplifier and did not work -which surprised me because these were the only 1 amp fuses the store had (I figured a 1 amp fuse is a 1 amp fuse). So I went back to Radio Shack and got some 3 amp slow blow fuses and these worked perfectly. Amp works and sounds fine now, but my question is:

    First of all, why are fuses smaller now than they were in the 60s? Secondly, am I making a mistake by running a 3 amp fuse when the amplifier clearly calls for a 1 amp? Logic tells me no, but I want to be sure.
     
  2. Trout

    Trout Member

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    Radio Shack carries 2 different sizes of 1amp slow blow fuses, you should need Model: 270-1021 | Catalog #: 270-1021 which is the correct size for the fuse holder.
    1.0-Amp 250V 1¼x¼" Slow Blow Fuse (4-Pack)

    If it does not fit, there might actually be a problem with the fuse holder iteslf.

    Using an oversized slo blow fuse will most likely ruin your power transformer in the event that something fails in the amp ( caps, tube, short)

    edit, Availabilty varies from store to store, often one store will not have the correct part and 10 miles up the road the next store does.
     
  3. Adwex

    Adwex Member

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    Logic should tell you yes. The 3 amp fuse will blow when the current exceeds 3 amps, but your amplifier was designed with a fuse that will blow at only 1 amp. You are allowing 3 times the current as originally designed. Bad logic. Bad idea.
     
  4. zep41

    zep41 Member

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    good info there -- thanks.

    so your saying that an oversized fuse (meaning a fuse with a higher amp rating than the amplifier calls for) can ruin the PT?
     
  5. Trout

    Trout Member

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    :agree


    Exactly what he said,
     

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