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Which fuse for Mesa 400+?

Discussion in 'Amps and Cabs [BG]' started by krovx, Sep 6, 2008.

  1. krovx

    krovx Thump or Bust Supporting Member

    Mar 11, 2003
    Michigan, USA
    I called Mesa and the gentlemen told me the fuse I need is written on the head, fair enough. It says 6.25A slo blo. I have gone to three hardware stores and cannot find this fuse. I did a search on TB, and a lot of the guys have noted that they use 8A slo blo fuses for their 400+, and the 6.25 is for 400's. Mine has 12 power amp tubes, and 4 preamp tubes, so I am quite sure it is a 400+. What should I do? Any suggestion where I can find a 6.25 if that is in fact the correct fuse?

    Appreciate the help, internet searching is not coming up for much for me.
  2. I just picked up a bunch of 6 1/4, 250 volt slo-blow fuses at my local ACE hardware. I have two 400s, and that's what the front panels say.
  3. anderbass


    Dec 20, 2005
    Phoenix. Az.
    My 1993 400+ is factory labeled for a 8 amp slo-blo fuse.

    I'm thinking its possible your 400+ may have mistakenly had a left over 400(non-plus) switch panel with its 6.25 amp fuse labeling instaled when the amp was originally assembled. (I'm pretty sure that would be the only difference between the actual switch panels of these two models)

    I was wondering what size and type fuse your amp had when you got it?
    How long did this previous fuse last, and did you buy this amp new or used?
    If it came to you with a 6.25, did that fuse only blow after the very first time you really cranked the volume up?
    (that could explain why an undersized fuse would finally blow in an otherwise good amp, but of course yours may indeed have a problem)

    This link to a Mesa schematic shows an 8 amp fuse for domestic 400+ models. (and a 4 amp fuse for export 230/240 volt models) It makes no mention of the 6.25 fuse that was used in the earlier 6-powertube 400/D-180 models.

    I'd suggest you send a pm to T/B member Benjamin Strange:
    He used to work for Mesa/Boogie and might be able to contact one of the old timers there that might know for sure if any (very early?) 400+ models were indeed labeled for a 6.25 fuse. (if they ever did, they may have soon discovered the mistake and then changed the rating to an 8 amp fuse)
  4. krovx

    krovx Thump or Bust Supporting Member

    Mar 11, 2003
    Michigan, USA
    Thanks for the reply Ander.

    I am guessing it is a misprint on my amp. All of the pictures I have seen from other 400+ all say 8.0A. It did have the 6.25 fuse in it when I bought it used, and has worked fine but this one gig. I did see someone mention that anytime they turned up beyond 7 on the master it would blow a fuse, and I usually keep my volume at 1-2 turning it on. Then gradually move it up. This time it was set on 7 since I was in a rush to sound check. Wondering if that surge might of blown the fuse. Regardless, it probably should be a 8.0A in there. I am going to take the tubes out and inspect them and push them back in. Thanks for the suggestion!
  5. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    Mesa has made small changes in the 400+ over the years - this is why every manufacturer states "specifications are subject to change without notice". If it says 6.25 slo blow, then get 6.25 slo blow. If you get a higher rated fuse, it won't blow early enough to prevent a possible major meltdown in your amp.

    I usually find the correct fuse at Radio Shack. Failing that, I look on ebay, or sometimes I just have Mesa send me a pack of them.
  6. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    Try looking for an actual electronics store near you. Those big chains NEVER have anything I need.
  7. krovx

    krovx Thump or Bust Supporting Member

    Mar 11, 2003
    Michigan, USA
    Thanks for the details folks. Found fuses at a hole in the wall.

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