Tube Amp Amperage Draw?

Discussion in 'Amp Central Station' started by MacFangus, Jul 13, 2020.

  1. MacFangus

    MacFangus TDPRI Member

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    Does anyone know how much amperage a 50 tube amplifier draws? I'm thinking about getting a variac that's rated at 1.75 amps to run my Marshall at 115VAC to 117VAC. Lower voltage settings will result in increased amp draw, of course... but, will it exceed 1.75 amps at high volume @ 115VAC voltage setting?
     
    Last edited: Jul 13, 2020
  2. Blrfl

    Blrfl Tele-Holic

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    Every electrical doohickey sold in the U.S. is required to have a plate somewhere that lists its maximum power draw. That figure will be in watts. Divide that by the voltage and you'll get current in amps.
     
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  3. dan40

    dan40 Tele-Afflicted

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    Yes...I believe the mains fuse value for a 50 watt Marshall is 3 amps. The fuse will be slightly overrated to prevent premature failure so I would guess the amp draws 1.5-2 amps under heavy load. That's just a guesstimate but I would look for at least a 5 amp variac at the minimum.
     
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  4. schmee

    schmee Doctor of Teleocity Silver Supporter

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    A 50 watt Bassman draws about 1.5 amps
     
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  5. MacFangus

    MacFangus TDPRI Member

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    Thank you, everyone. To be sure, I'll get something that's rated at 4 amps or higher. I just thought a smaller size variac would be a better fit.
     
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