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Quick AMP / Fuse Size Question

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  • Quick AMP / Fuse Size Question

    Ok, I'm waiting for my Rockford Fosgate 500X to get repaired. In the meantime I've borrowed a Sony 25 X 2 amp. I'm going to be powering my four door speakers with it (I know it's not much juice but I had ALL my speakers running through my amp so right now I have NO sound).

    I used a 50AMP blade fuse for my RF but it blew. I went to Wally World today and all that had was 40AMP fuses.

    My questions are:

    1. Can I use the 40AMP fuse for this Sony amp?

    2. Can I continue to use the 40AMP instead of a 50AMP when I get my RF amp back.

    P.S. The fuse I'm talking about is on the powerline 6" from the battery.

    Thanks a lot!
    Current Vehicle: 2007 Dodge Nitro

    Second Vehicle: Sold it :( 2005 Dodge Ram 1500 Quad Cab

    First Vehicle: 2003 Ford Ranger

  • #2
    Have you bought the 40 AMP fuse yet? If so, try it, the worst that can happen, the fuse will blow. But 25 watts x 2 channels = 50 watts /10 volts = 5 Amps at less than perfect battery conditions... you could probably get away with a 10 amp fuse.
    2007 Honda Fit Sport 1.5L SOHC-VTEC


    • #3
      watts = amps * volts. So, if you maxed out that amplifier, you'd only need 50/14.4 (I have no idea what that 10 volts was all about, charging voltage is 14.4 in a 12 volt car system). So a 3.5 amp fuse would be enough. You primarily want to protect against short circuits as that sony amp is essentially disposable. When you get your Rock back, you're looking at 34 amps. a 40 watt fuse is perfect! However, I'd stop by Napa or Pep Boys and get a bus fuse. I don't trust anything from Walmart.