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using US 9V power transformer in UK

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by spaceboy, Jun 28, 2004.

  1. spaceboy

    spaceboy Member

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    Jun 10, 2004
    Location:
    Dundee, Scotland
    well, got myself a lovely Replifex from the US thinking "right, well it was stupid getting the Mesa 20/20 from the US - caused so much hassle and bother and expense, but this'll be fiiiine, i just need a new 9V transformer - easy!"

    I get to the local (very limited) electronics store and realise that the replifex needs AC power, and draws 1.5A, neither of which can be accomodated by the store's transformers. so I figure - "aha! i'll phone up Rocktron's UK distributor and just order a UK power supply! - easy!"

    So the guy says, after consulating the folks in th guitar department, that I don't need a new one, just an adapter - the little 2 prong to 3 prong majigger, which seemed fine. better than fine, he sent it off to me free of charge! but then I started thinking... if someone had suggested this to me beforehand, i would have assumed that one of two things would happen...

    1) the transformer, made to handle 120V, would simply pack in, burn out, blow or whatever.

    2) it would give out a voltage higher than 9V... I don't know quite how transformers work, but it seems logical that given twice the supply voltage, it might give twice the output... which would be very, very bad for my precious Replifex...

    so, do these people know what they're talking about? are my fears justified?

    thanks for your help!
     
  2. John Phillips

    John Phillips Member

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    Location:
    Scotland
    You are VERY right to be cautious. Without knowing what type of power supply it is, exactly what you're expecting - #2 especially - could well happen.

    If it is a simple step-down transformer power supply (an AC one doesn't need any other components than the transformer itself), if you double the voltage in you will double the voltage out, it's that simple.

    Whether this will cause trouble with the Replifex I don't know - some equipment is very tolerant of extremely wide variations and regulates itself internally. There are also other types of power supply which can take a wide variety of input voltage and produce the same output - in exactly the same way.

    If Rocktron say it's OK, it may be - but I would take the risk of becoming a pest and calling them again, explaining why you're worried. If they can tell you why it's safe, it is.
     
  3. spaceboy

    spaceboy Member

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    hey, thanks John. i think that's just what I'll have to do - phone em back tomorrow and ask them to double check that it's ok, and definately explain WHY it's ok.

    cheers!
     
  4. Old Fuzzface

    Old Fuzzface Member

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    Jan 4, 2002
    Location:
    Cheshire, UK
    Check the labelling on the PSU. If it's legal in Europe, it will have an input voltage written on there.

    For instance, if it says 90-240V, it's auto-ranging and all is cool.

    If it says 120V, you're screwed.
     
  5. spaceboy

    spaceboy Member

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    Jun 10, 2004
    Location:
    Dundee, Scotland
    yup... 120V...

    right, well i'm off to phone em up.
     

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