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  • ...fuse = 30 cents, beer can = $480

    Allright guys and gals, I feel compelled to discuss a subject that has been the death of many a fine amp........ fuses!

    As most of you know, I am an amp tech and I've seen my fair share of senseless destruction.... But this week alone has triggered me into action to inform the general public about these apparently misunderstood devices...

    Fuses are current rated "circuit breakers" specifically designed to protect both you and your gear from unsafe operating conditions. Which means if you should blow a fuse, chances are something bad has happened that caused an excessive amount of current to be drawn. Half the time this can be attributed to external factors that you, the user, have no control over....(power surges, improper wiring at facilities.....and most notably, for those on tour, generators!!) In 95% of these cases, simply replacing the fuse with the correct replacement will get you back up and running with no damage done. (Assuming the external problem has been solved).

    However, replacing a fuse with one that is not the same amp rating is DUMB!

    The people who engineered your amp (or any other device) know what the maximum current rating is, and specified a rating to ensure proper operation without burning anything up....(most of the time!).....Especially for tube amps!

    If your amp has an externally accesible fuse, do yourself a favor and go get some spares now that you don't need them, instead of "panicking" when you do need one. They will have an ampere rating (ex. 3amp) and usually will specify "fast blow" or "Slow blow"....SB for short.

    If your amp ever blows a fuse, simply replace it with the same value fuse and if it blows again.....do not keep trying, and take it to a tech.....No one has ever succesfully "powered" their way through an amp problem...EVER!!!!!

    No, I haven't just bought stock in a large fuse company, and the "beer can" story (among others) is as follows:

    Got a Mesa 400+ Bass Amp in for repair, this baby runs 12....that's right 12....6L6's for output tubes! Amp didn't power up, and a quick check of the fuse revealed the 8amp fuse had been replaced by a small curled up section of a Bud Light can! (amp rating unknown.... ) Further analysis indicated two diodes in the rectifier circuit were shorted, which was the original problem....diodes = $0.65 each, so what would have been a $90 max repair bill now has jumped to almost $500 because the Power Transformer is fried....and it is one massive transformer!...

    why????... because apparently a replacement fuse was not readily available, even though it would have blown too, it would not have destroyed the tranny or fried the traces off the PCB. Just would have let the owner know there's a bigger problem.

    Although that was the first one this week, I've been getting way too many amps in with incorrect value fuses. Trust me, I am all for a more thorough exploration of amps and more and more people are trying differing tube setups and pushing amps harder and harder....but be wary, fuses are often your only safeguard against meltdown.....unfortunately amp "victim" number two was a priceless piece of history!!!!!...(those with a weak stomach may want to leave now.)








    1964 Fender Blackface Super Reverb...... originally blew fuses because the owner was unaware that the "spkr out" jack has to be used before the "ext spkr" will do anything......simple enough....
    His solution was a 15 amp fuse which promptly annihilated the power tranny, one of the 70uf filter caps and worst of all......because the transformer didn't burn up fast enough, it fried all 4 original speakers!!!!..........(chain succession failure!)

    ...the 30 cent fuse never blew!

    all he had to do was plug the speaker's into the spkr out jack instead of ext. spkr.........

    Just Fwiw..........

    Jeff Seal
    ..lots and lots of toys!

    "...swords and tequila, carry me through the fight!"

    "I am Phil"....
    www.houstonamprepair.com

  • #2
    Re: ...fuse = 30 cents, beer can = $480



    UNBELIEVABLE!!!
    Last edited by Jonny R; 08-18-2004, 07:19 PM. Reason: Excess smacks

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    • #3
      Re: ...fuse = 30 cents, beer can = $480

      I may make myself look really stupid here, but how do you know if you've blown a fuse? I have a bluesbreaker, and it recently stopped working. When I turn it on, there is a very quiet hum coming out of the speakers, but thats all that happens. I tried connecting it to a speaker cab (with correct ohm rating) and the same thing happened there...light hum coming from the speakers, but that was it. I haven't touched anything on it yet, cause I've been trying to find out on here what might be wrong before I go prodding around and pulling tubes in and out, etc.

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      • #4
        Re: ...fuse = 30 cents, beer can = $480

        Originally posted by Mojoe01
        I may make myself look really stupid here, but how do you know if you've blown a fuse? I have a bluesbreaker, and it recently stopped working. When I turn it on, there is a very quiet hum coming out of the speakers, but thats all that happens. I tried connecting it to a speaker cab (with correct ohm rating) and the same thing happened there...light hum coming from the speakers, but that was it. I haven't touched anything on it yet, cause I've been trying to find out on here what might be wrong before I go prodding around and pulling tubes in and out, etc.
        Mojoe, asking when you don't know is intelligent thinking!

        If you unplug your amp and let it sit for a minute, feel free to remove the fuses and inspect them....depending on which fuses are in there, chances are good you can see a small wire going from one end to the other, since you have a BB, you also may see a small "spring" in there with a short piece of wire on one end. If it's bad, you'll see the wire burnt or the spring collapsed with the wire missing from the end. Given what you described, very doubtful you have a blown fuse. Is yours a RI..(with tremelo...don't you just love how they purposely misspell this!) or an original?

        I will be more than happy to help you track it down....

        JS
        Last edited by Jeff Seal; 08-18-2004, 01:15 AM.
        ..lots and lots of toys!

        "...swords and tequila, carry me through the fight!"

        "I am Phil"....
        www.houstonamprepair.com

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        • #5
          Re: ...fuse = 30 cents, beer can = $480

          Jeff is 110% right !! I'm amazed at the ignorance of many musicians !
          Here's a tip I was told as a young musicain by a older wiser guy.
          Find the propper value fuse your amp take's, Buy a pack for a few
          bucks. Than Duct tape the pack somewhere on the inside of your
          amp cabinet. Again common sence helps. Place it somewhere smart!
          Not near your tubes Now you have backups
          http://www.soundclick.com/whirlwindbluesrevue

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          • #6
            Re: ...fuse = 30 cents, beer can = $480

            Just thought id add my two cents with a little story about my komet i recently bought. For those of you who know its not a cheap item, and a damn fine amp! When i got it however i inspected all the parts and most of all checked the fuses, and saw that the slow blow fuse was in fact loaded with the correctly rated 3amp slow blow fuse...but the high tension fast blow fuse socket which was supposed to be loaded with a 0.75amp fast blow fuse, was also loaded with a 3amp slow blow!

            Could this have spelt disaster for my lucious komet?
            My Soundclick page.

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            • #7
              Re: ...fuse = 30 cents, beer can = $480

              This amp head case has an extra compartment. Inside that compartment is a set of fuses and tubes jammed into the bottom, in case of that horrifying situation of standing onstage with a dead amp. Good post. Good info. I hate to admit it, but I've used that 'curled up piece of Bud can' fuse fix. I lost a $50 volt meter doing it.

              Originally posted by Boogie Bill
              I've got 60 guitars...but 49 trumpets is just...INSANITY! WTF!

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              • #8
                Re: ...fuse = 30 cents, beer can = $480

                Aaaah.... another great info dudes! An admin should place this thread in the "Vault".

                I knew fuses in amps were our safety jackets... but I always forgot to buy some spares... I'm running to the local hardware store to buy some right now. Thanks for shaking my brain this morning!
                Edwards Jimmy Page, Fender AmDlx Strat, PRS CE24, Edwards E-FV, AGILE Valkyrie Double-neck, Ibanez EP9. Metroamp 50w, Fender SFSR, Blackstar HT40 VP

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                • #9
                  Re: ...fuse = 30 cents, beer can = $480

                  Now don't I feel dumb. I've got a couple extra tubes laying around, but absolutly no fuses for my amp head. Thanks for the wake-up call, Jeff.
                  Duncan Pickups in currently in use: '59 (rewound to PATB-3)/'59, Custom 5/AP2H, Tapped QP set for Tele, Crazy 8/Cool Rails, Custom 5/Phat Cat, SP90-1/SP90-2, SHPR-1b/SHPR-1n, SMB-5D

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                  • #10
                    Re: ...fuse = 30 cents, beer can = $480

                    Yeah, its one of the reissues, I'm not sure what year exactly though. I got it off ebay last August, and it's been pretty tempermental. I never played it much during the year (away at school) and then I started really getting into it this summer, and then...it stopped working.

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                    • #11
                      Re: ...fuse = 30 cents, beer can = $480

                      I have to go to Home Depot in a few & I'm grabbing some fuses........

                      But here's another semi-stupid question: If you have a used 22 year old amp, how do you know if the tube you're taking out & replacing is the correct one??? What if somewhere along the line, one of the previous owners just threw in whatever fuse was laying around?

                      Guitars: Frankinstein TeleBird/Classic Vibe Esquire w/BG-1400/Martin 000-28EC
                      Amps: 3rd Power Dream Solo 4 '68 Plexi/Port City Wave 2x12
                      FX: Skinpimp Faceplant/Skinpimp 3OD/Flyin' Dragon


                      https://itunes.apple.com/us/album/fa...wn/id786464154
                      http://www.cdbaby.com/cd/seanhanley

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                      • #12
                        Re: ...fuse = 30 cents, beer can = $480

                        I always say "Stupidity will be punished"...

                        This is proof that Im right
                        Zerberus Industries: Where perfection just isn't good enough.

                        Listen to my music at http://www.soundclick.com/infiniteending and www.subache.com

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                        • #13
                          Re: ...fuse = 30 cents, beer can = $480

                          Originally posted by Zerberus
                          I always say "Stupidity will be punished"...

                          This is proof that Im right
                          Ha Ha!!` My saying is Stupidity always finds a way"
                          Not that I'm a rocket surgeon myself But it's important
                          to think B4 you act !!

                          Originally posted by PUCKBOY99
                          But here's another semi-stupid question: If you have a used 22 year old amp, how do you know if the tube you're taking out & replacing is the correct one??? What if somewhere along the line, one of the previous owners just threw in whatever fuse was laying around?
                          The propper value sould be screened on the back of the amp ,Or the
                          fuse holder cap. If not? Try to find a schematic for the amp.
                          BTW , One more tip... When buying a used amp ALWAYS check the fuse
                          To make sure it's the right value ?? If it has the wrong fuse in it, This
                          could mean there's a problem??
                          Last edited by kmcguitars; 08-18-2004, 10:22 AM.
                          http://www.soundclick.com/whirlwindbluesrevue

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                          • #14
                            Re: ...fuse = 30 cents, beer can = $480

                            Good thread!
                            If I may ask, what does a T behind the amperage mean? (ex. Tube fuse I: 500 MAT, that's 0,5 Ampere with a T behind it?)
                            Is there a big difference between slow blow or fast blow? If a fuse goes does it matter if it goes fast or slow?
                            I imediately checked my fuses after reading this, all is ok.

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                            • #15
                              Re: ...fuse = 30 cents, beer can = $480

                              Wah a bad horror story..poor Fender amp

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