How Much Power can Cranked 100 Watt Superlead Produce?

Discussion in 'The Workbench' started by matttornado, Sep 9, 2019.

  1. matttornado

    matttornado Well-Known Member

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    Does anyone know or have an idea how many watts a full cranked metal panel 1959 Superlead actually puts out? It's over 100 watts, correct? I'm sure it varies from amp to amp of the same model. Mine is a 1974 modified for EL-34s with 480 V on the plates.
     
  2. anitoli

    anitoli Well-Known Member

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    Peak to peak prolly 160w.
     
  3. Matthews Guitars

    Matthews Guitars Active Member

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    About 100 watts before onset of clipping. Calculating clipped power is more complicated but the thermal equivalent is probably about 200 watts at full steam.

    We know that a 100 watt amp will destroy a 4x12 full of 25 watt Greenbacks if run flat out for a while. That's why you should run full stacks, not half stacks, if you deck it.
     
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  4. john hammond

    john hammond Well-Known Member

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    ' Watts' means how hot literally the four tubes get( 4 x 6l6gc and 4xel34 can both be at 100 watts but they'll make different decibel volume).
    if youre matching the amp to a cab, then watts is a good way to measure power because speakers are also rated for heat.
    How many decibels is a more effective question to ask if you wanna know how loud the amp is
    -130db?
    i think johan segeborn actually measured one with a db meter dimed
     
  5. ampmadscientist

    ampmadscientist Well-Known Member

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    100 watts RMS, that's how we (the industry) measures power.
    The peak power is fairly meaningless because we use RMS as the standard.
    No, your 100 watt amp does not produce more than 100 watts RMS, unless you modify the power supply.

    Amps are measured as a clean sine wave, that is the industry standard.
     
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  6. JohnH

    JohnH Well-Known Member

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    I think you are considering this to identify an upper bound for heat and power dissipation?

    Maths says that if a clean sine wave is putting out 100W RMS power, then pushing it to a square wave of the same amplitude doubles the power.

    But thatd not sound good to anyone!

    Id guess a x1.5 factor is a more likely max.
     
  7. john hammond

    john hammond Well-Known Member

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    - ah yes, id forgetten about this, theyre rated at the max clean before dirt. good info ampmad
     
  8. ampmadscientist

    ampmadscientist Well-Known Member

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    If the distortion is measured it's not considered a fair comparison to other amplifiers.
    That's why the "clean" standard of measurements, to keep the playing field level.
    How much clean power the amp will produce before distortion?
    (distortion = power amp clipping when the power supply is maxed)
    The amount of max clean power is the benchmark.

    The real factor guitar player is looking for = sensitivity.
    Even though guitar player does not know or understand this concept of sensitivity.
    Guitar player wants the amp to break up in a nice way during over-driven crunchy tones.
    The second factor guitar player seeks is headroom for clean tones, where the amp doesn't break up.
    It seems like mistakenly this is all above attributed to wattage. But it's really not the wattage.
    It's sensitivity of the input and it is loudness = efficiency not necessarily wattage.
     
    Last edited: Sep 9, 2019
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  9. Frodebro

    Frodebro Well-Known Member

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    This is also the reason behind the popular myth that “tube watts are more than solid state watts.”

    No, they’re not. 100 watts of clean power is going to be the same regardless of the circuit producing it. The confusion comes when people push their tube amps beyond that point of clean output- tubes will continue to increase their output well into the realm of clipping (and generally sound good doing it), solid state amps hit the wall right about the time they reach their full rated clean output.
     
  10. ampmadscientist

    ampmadscientist Well-Known Member

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    “tube watts are more than solid state watts.”

    Well, to me a SS Mode 4 300 watts is about the same loudness as a 100W Plexi tube amp.
    Maybe it's just me, but I know the speaker is saturating.
    That saturation of the speakers is actually the limit.
    If there was a speaker that never saturated, it would just keep getting louder and louder...
    but in the real world that's just not how it works out.
     
  11. Frodebro

    Frodebro Well-Known Member

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    Put them both on a scope and observe the sine wave when the tube amp starts getting louder.
     
  12. JM5010

    JM5010 Member

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    Jeez. 160w?

    Imagine how much power a cranked major produces with the Blackmore mod.
     
  13. Matthews Guitars

    Matthews Guitars Active Member

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    One of my amps is a Fender Super Twin Reverb. Three pairs of 6L6 output tubes, 180 watts clean output power, and according to Fender, 395 watts peak music power. It's frankly just bonkers. There's no way that a clean surf guitar tone should even be POSSIBLE at the volume this amp can achieve, but yes, it'll do that! It'll keep up with a Major.
     
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  14. neikeel

    neikeel Well-Known Member

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    It is easy enough to measure with a dummy load resistor and a scope, clean, clipping and dimed. Measure the voltage across the resistor and extrapolate back, using peak to peak or dividing by root 2 for RMS.
    or what have I missed?
     
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  15. DonP

    DonP Member

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    My 1979 100w with 6550's hit 120w clean.
     
  16. Matt_Krush

    Matt_Krush Well-Known Member

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    One thing most people also don't account for, no amplifier can create more output power than what is being received.
    An ideal amplifier is Pin = Pout

    We are far from an 'ideal' amplifier.
    If you are at nominal voltage; 120VAC and are limited by what? a 2A fuse, you can never see >240watts of output power.
    Factor in losses (amp efficiency) and bias settings...I'd wager 100watts clean power output is pretty close.

    I really get a kick out of those that think they have a 5000w PA.
    Reallly? 120V x 20A (not factoring in the 80% fuse de-rating) is only 2400w (and thats the non-existing ideal amplifier case).
    The power cord on the amplifier is only rated to carry 10A...so now you only have 1200W. Factor in losses/amp efficiency...depending on class of amplifier...maybe 800wRMS is true capability.
     
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  17. matttornado

    matttornado Well-Known Member

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    What about when volume is cranked on 10? That,s what I'm curious to know. I don't play my Marshall amps clean ever.
     
  18. ampmadscientist

    ampmadscientist Well-Known Member

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    Peak to peak voltage (clean voltage only) divided by .5 = peak voltage.
    Peak voltage X .707 = RMS voltage.
    RMS voltage divided by the load resistor = current.
    RMS voltage X current = apparent wattage, (VA) not the true power. Only the true power is wattage.
    Apparent Power (VA) X efficiency = true wattage.

    Everyone in this industry is measuring apparent power, not true power which is watts.
    Unless you have a number for "efficiency," you have no true wattage measurement.
    That's ohms law.
     
    Last edited: Sep 12, 2019
  19. ampmadscientist

    ampmadscientist Well-Known Member

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    "My 1979 100w with 6550's hit 120w clean."

    Measured by what method?
     
  20. john hammond

    john hammond Well-Known Member

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    the power output of the amp is defined by the power supply of that amp.
    if 250ma peak is all that power supply can provide for the h.t taps, then

    250ma ( .25A) x 470v ( plate voltage ) = 117 ( peak ) watts

    the thing is, this doesn't account for losses, which can be half.

    i think we are being lied to.

    edit- its worth mentioning 68 - 69 100 watt marshall power transformers are rated at a mere 150ma for the H.t.
    somethings amiss, and it aint my maths, its too simple to fuck up.
     
    Last edited: Sep 12, 2019

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