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Elevated AC heaters?

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  • Elevated AC heaters?

    nevermind. sorry i asked
    Last edited by daz; 11-04-2016, 03:40 AM.

  • #2
    Not resistance, voltage. Lift them to +10 or +20vDC.
    Education is what you're left with after you have forgotten what you have learned.

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    • #3
      What is elevated AC tho? (which i have heard mentioned in my search) Does elevating AC mean changing it to DC?

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      • #4
        No, it means exactly connecting the heater center tap to a DC voltage. The AC across the winding is unchanged, the heaters still see 6vAC, but now it also sets 10v above ground. Just like the signal AC on the plate of a tube is sitting at 200v DC as well.
        Education is what you're left with after you have forgotten what you have learned.

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        • #5
          On the valve wizard site it shows the DC taken from the HV in the top image below thru a voltage divider and has a cap. If i use a 220k on the top and 10k on the bottom (3 watt resistors?) will that be workable? And if so, what about the cap, can i use a 50 or 100uf ? The voltage at say the PI node is around 300v i believe so that divider would = around 13v.

          Click image for larger version

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          • #6
            Originally posted by daz View Post
            (3 watt resistors?) will that be workable?
            Is this going to be another multi-page thread about Electronics 101?

            Do you know the equation for calculating power dissipated by a resistor?
            WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
            REMEMBER: Everybody knows that smokin' ain't allowed in school !

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