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Amp fuse experts!! S4A or T4A ???

Discussion in 'Amps and Cabs [BG]' started by sucho2000, Apr 28, 2010.

  1. sucho2000


    Nov 19, 2009

    I have got Markbass LMII
    and using it in Australia... 240V 50HZ

    Its manual says I need use T4A 250V fuse (Slow-Blow?)

    So I went to electronic shop and asked for Slow-blow 4A fuse
    and this guy gave me "S4A"...

    I am using the S4A fuse at the moment with no problem
    But, is it OK to use this instead of T4A ???

    I am complete noob on these kinda issues, So :help:


  2. sucho2000


    Nov 19, 2009
    Anyone? Noone??
  3. I'll have an answer in a few minutes - I posted it on a NZ site.
  4. Got it-

  5. sucho2000


    Nov 19, 2009
    Umm... So....

    Can I use it? :bag:

    Mine doesn't seem to have a motor in it,, lol
  6. Yeah - it's the purpose for which they are made that make them unique.

    Slo-Blow is the mystery value and it's what you amp-maker wanted. I say if it fits, has the same specs as to total amps allowed, and it;s the same shape-size and connex, then go for it.

    I also found out that the "T" style MIGHT be German in original design. Could be wrong with that country of origin assessment though. -

    But if at the amps for the one which it replaces and if it's so-spec'd and if it fits, use it.
  7. sucho2000


    Nov 19, 2009
    Thanks Surfer Joe!!! :bassist:
  8. No, you probably can't use it. Electrically, they are the same but physically,
    the form factors are different. The Edison base is a generic fuse base
    that looks like the bottom of a light bulb. The rejection base looks
    similar but has different threads to prevent the wrong value of fuse
    from being screwed in.


  9. Those are on the amp???? They must be huge! In the Americas we used to have similar looking fuses in our main power panels and appliances. They've almost disappeared nowadays replaced by breakers.

  10. BbbyBld


    Oct 13, 2005
    Meridian, MS
    I think they are basically the same thing.

    The old term was "slow-blow", and some companies now sell them as "time delay".

    There are newish regulations that require certain fuse information to be printed somewhere on a product.

    Here are two examples of that standard:

    F1AL = fast-blow, 1A, low breaking capacity

    T1AL = time delay or slow-blow, 1A, low breaking capacity

    If there is an H on the end, it means high breaking capacity, but you probably won't find that outside of an industrial setting.
  11. Yeah - 'cause you could stick a penny in it when the fuse blew and then you'd have no protection at all.
  12. Loveformetal


    Oct 25, 2010
    I lost the fuse to my brand new acoustics b200h amp on my way back from it's first gig.
    It needs a t4al 250v fuse and i've spent countless hours visiting 4 different electronics stores, two music shops and surfing the web and i cannot find one. If anyone could help me locate one it would be amazing. I havent been able to use it for 6 months now and NEED it. Any help at all is greatly appreciated.
  13. I've got the B-200H owner's manual right in front of me and there's no way to access any serviceable fuse from either the front or back panel that I can find - nor does Acoustic make mention of it in that book.

    How did you lose an internal fuse - as that's gotta be the only place one could reside like in both my B-450 or my B-600H amps?

    The last time I was into the B-450 - which is just another B-600H cab-mounted - I never even noticed a fuse on the PC Board either.

    I'll go back and check the pixs I took of my amps - but like I said - HOW'D YOU LOSE A FUSE?

  14. OK - here's the front view in a PDF straight from Acoustic, of your B-200H.


    And the rear:::


    .....and I don't see any fuse holders anywhere.
  15. Loveformetal


    Oct 25, 2010
    If you look closely i believe you may be able to see a fine line 2/3 of the way torwards the right side of the AC inlet. I'm trying to upload pictures but since my phone is making it difficult to do any my computer is not working i'm not sure if thats possible.
    The ac inlet stands verticle with a glass tubular fuse just to the right side.
    Also i have the owners manual and that's of no use.
  16. You're prolly right - I never noticed - and Yes, the owner's manual is pretty useless - but it has some nice pictures.

    Technically, the manual is a flop.

    Right after my breakfast, I'll spin my B-450 around and look for a fuse* area on it - but I'm so anal I wonder why I never saw anything there before.

    Of course, the 'T' in the name of a fuse means it's a time-delayed device that can hold a surge when you first turn it on, and if it were the 'S', that means slo-blow.

    In the past when I couldn't get either for whatever reasons, I'd use an 'AGC'-type and they sufficed. Don't worry about the voltage rating (in your cited situation= 250V) - it's the AMPS that are important.

    Old f@rts can learn too I guess.

    * - rectally aware.
  17. Afterthought: You never told how you lost the fuse.
  18. Loveformetal


    Oct 25, 2010
    I played it for about a month, took it to it's first gig. They wanted us to into their PA and then their bassist asked to use it and i let him, as well as telling him to help my vocalist put it in his car since i had to go to work.
    The next day we were setting everything back up and the fuse, dual 1/4 patch cable and AC cord were gone.
    I asked the guy about it and he offered me money.
    I didn't take it because he seemed like an honest guy.
  19. That's exactly why I don't let anyone use my gear. Either they don't care (where's theirs?) or they mess it up.

    I watched a guy 'borrow' a bass for 'just one song' and when he got done, he raised it up over his head to take it off and broke a tuner off on the low overhead - and then when we were looking at it, he had been wearing a big belt buckle and dug some serious grooves into the back of the 3-day old MIA bass.

    Then the guy who borrowed it said: "You must've scratched it up yourself, 'cause I didn't" --- even though we could see his buckle.

    He also said: 'You can get some three dollar Squier tuners and I don't have three dollars anyway".

    Your situation just sounds mean and nasty to me: stealing the patch cord and the ΒΌ" instrument cable is one thing, but swiping the fuse is just rotten.

    Suppose he's trying to tell you something?

    I got some pixs of the backside of my B-450, and it's the same as my B-600H too:::



    No fuse - but I've got a breaker.
  20. Actual_Malice


    Nov 26, 2011
    i have a Marshall AVT150H and my fuse blew an ive been looking for a fuse for months with no luck. My fuse says it a .4 125volt fuse but when i contacted marshall they told me its a T4a fuse an everywhere ive looked says that type of fuse is 250v . please help!!!!!!!!

    ps. my amp says it will take a t4al =117 volt or a t2al =230 volts what does this mean?

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