Confused about volts, mA, watts

Discussion in 'The Effect effect' started by Socrates_dct, Mar 19, 2021.

  1. Socrates_dct

    Socrates_dct Strat-Talk Member

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    Hallo buddies,
    I baught a small vox ac2 amp (it's a great lil thing) to be able to take it with me anywhere. It fits in the pocket of the guitar cases..
    It works with 6 aa batteries but you can buy separetely a supplier. Vox says "DC 9V 500mA or higher". What's the difference if buy a 500mA or a 1000mA or 1700mA? Which choice is better?
    Sorry if my question is very newbish Im newbee too :thumbd:
    Thanks a lot!
     
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  2. The-Kid

    The-Kid Dr. Stratster

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    You need at least 500ma at 9 volt DC.


    Any less and the device may not turn on, no damage, it just won't turn on. If you feed say 2000ma or 3000ma it does not matter it only pulls what it needs, so ..... run it at 500ma or higher, DC at 9 volts. Mission Engineering makes the 529M, should fit the bill
     
  3. Malurkey

    Malurkey Senior Stratmaster

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    Hi there!

    Volts * Ampère = Watt

    So what that says is that you need a power supply that delivers 9 Volt and a current of at least 500 milliamperes. It doesn’t matter if the power supply can deliver more, as the amplifier will draw no more than 500 milliamperes. But if it’s less, you don’t have enough current to power the amp.

    Note that too many Volts is a bad thing, and that can seriously damage the amp. Too few Volts could damage your amp in the long run, but not as quickly as too many. So get the Volts right, it’s important! :thumb:
     
  4. fezz parka

    fezz parka fezz parka

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    None. You'll draw the current you need. If you need 1000mA...get 1000ma or higher.
     
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  5. The-Kid

    The-Kid Dr. Stratster

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    The volts are important to get right as well a AC vs DC BUT altleast use required ma or higher.


     
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  6. Socrates_dct

    Socrates_dct Strat-Talk Member

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    Thanks you all mates! It's clear now :thumb:
     
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  7. Socrates_dct

    Socrates_dct Strat-Talk Member

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    Hmmm I think I have one more question.. The quality of the supplier does play any role? I mean is it tge same if I buy a bosch suplier or a cheap chinese? Maybe a cheap supplier creates "noise" through the amp? I ask because the music-strores sell suppliers that are made by factories in music industry, like "specific" for use on amps, pedals etc
     
  8. ThreeChordWonder

    ThreeChordWonder Strat-Talker

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    Cheap Chinese is fine.
     
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  9. Stevn

    Stevn Senior Stratmaster

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    It will only use as much as it needs. The mA you quote means more current is available than you need. You shouldn’t even heat it up really.
    If the number is smaller than your device mA you cook the transformer from drawing too much current on your wall wart. Do the 1000mA even though the 500 will work. Let your budget be your guide.
     
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  10. AngeloEvs

    AngeloEvs Strat-Talker

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    I would look for a Regulated DC Power Supply, some of the cheap chinese imports are unregulated with output voltages higher than the quoted 9V by an unacceptable margin, some can be quite noisey as well. 1000ma will give you more headroom but it all depends on the actual current draw, if Vox recommend 500ma or higher I would go for the higher as the cost would probably be not much greater.
     
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  11. Stevn

    Stevn Senior Stratmaster

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    My favorite is E=I/R Mr Ohm! It gets you everywhere in the circuit!
    But your advice is spot on!
     
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  12. Socrates_dct

    Socrates_dct Strat-Talk Member

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    I ordered the truetone 1-spot 1700mA.
    Thank you all..!!!
     
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  13. fos1

    fos1 Senior Stratmaster Silver Member

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    Be sure to check the polarity of the plug that plugs into your appliance!

    Center positive or center negative if reversed can burn out your device.
     
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  14. Socrates_dct

    Socrates_dct Strat-Talk Member

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    Very helpfull advice! I checked the adaptor and it is ok. It has the proper sign. I was searching the polarity that vox demands and I didn't find any recommendation. But I found a comment on amazon from a user who said he firstly bought a wrong polarity supplier and then he changed with another one that has the same sign like mine (+ O -) meaning negative center polarity! Thank you!
     

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  15. fos1

    fos1 Senior Stratmaster Silver Member

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    Many times there is a polarity indicator molded or printed on the device near the power supply input socket. It is also frequently listed on the "specifications" label on the device.
     
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