Volt amps, and what they mean to me...

Discussion in 'Effects, Pedals, Strings & Things' started by R0ADHOUSE, Feb 16, 2015.

  1. R0ADHOUSE

    R0ADHOUSE Member

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    I have this line regulator that's good to 1200 volt amps. I'm not sure what this means to me practically. I want to run two 5 watt amps, and my quite large pedal board through it but I just don't know what it can handle. Any suggestions on how to estimate she limits in the fly? I have a 15 watt amp I might use as well instead of one of the 5 watt.
     
  2. R0ADHOUSE

    R0ADHOUSE Member

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    I hate to bump but I seem to be having trouble finding a clear cut answer
     
  3. Glitch Magnet

    Glitch Magnet Member

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    I would expect the regulator should self protect if you overload it, so I say just try it.

    That said, if you can figure out how many amps your entire rig draws, it is possible to convert "volt amps" to "amps" quite easily as follows:

    VA / volts = A or 1200 /120 = 10

    So, if your rig requires less than 10 Amps, then you should have no problem using that regulator.

    Check the power requirement specs for each of your amps and pedal power supplies, total up the Amps, and if it's under 10, you're golden.

    Also keep in mind, the published Amperage specs for each device are maximum, which you'll only approach if you're really crankin, or possibly if you power everything up at once. The actual current draw during typical use if probably quite a bit lower.
     
  4. to_be_released

    to_be_released Member

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    There's two things you need to consider - supply power needs and power output.

    1 volt amp is exactly equal to 1 watt. I'm not entirely sure why the regulator refers to volt amps rather than watts, but they are one and the same thing.

    An amp's power rating is based on their output power. A 5 Watt amp can send up to 5 Watts to the speaker(s). A hypothetical, 100% efficient amp would only draw that much from mains, but there is no such thing as a 100% efficient amp.

    Some amps will also tell you how much input power they require. The old Fender Frontman within arm's reach of my pc has a 15W power output rating, but requires 38W of input power. I can't easily see the power input necessary for my Mesa F50, but the necessary fuse is rated for 1 amp at 240V, so it won't be drawing more than 240W at maximum.

    Given those values, I highly doubt that running both 5 Watt amps will get anywhere near a 1200 volt amp limit. At the outside, each amp might draw 50W. A typical power supply for pedals might put out up to 2 Amps at 9 Volts, which is a mere 18 Watts. Even assuming a meager 10% efficiency, that'll use less than 200 Volt Amps.

    In short, I don't think you'll have any issues with a 1200 volt amp limit. Heck, I remember one gig where the entire band was running with a 2400 volt amp limit for two guitarists (with amps and pedals), a bassist (with amp), and a PA for vocals.
     
  5. R0ADHOUSE

    R0ADHOUSE Member

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    Thanks so much. This really helps. I had read that Volt Amps equaled Watts but I thought if it really was indeed the same the manufacturer would have just said Watts. Thanks so much!
     
  6. John Coloccia

    John Coloccia Cold Supporting Member

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    Watts and VA are different for AC power. I don't want really want to open a can of worms by giving a half-explanation because I don't have time to really do it right, but Watts is generally averaged over time, whereas VA is calculated with RMS Volts and Amps. Since you're not really getting close to the rating, there's no reason to worry about the fine details anyway.
     
  7. DisasterArea

    DisasterArea Owner, Disaster Area Designs and Alexander Pedals

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    For a purely resistive load watts = volt-amps. Whether it's AC or DC, it's the same. If you have a capacitve or inductive load you have to take the reactance / phase into account. For the purposes of a guitar amp you may assume them to be equal.
     
  8. R0ADHOUSE

    R0ADHOUSE Member

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    Again thanks!

    What it sounds like to me is I should have paid more attention in my physics class.

    PS love your products.
     

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