Tube DIY Asylum

• impedance of the 10H choke at 120Hz - throbbinnut 08:58:05 01/28/04 (6)
  In Reply to: This is really a BIG shoe to fill ! Base on what???? posted by cheap-Jack on January 28, 2004 at 08:13:39:

  Z = 2*pi*f*L = 7539 ohms impedance.

  But like you and others said, you don't have to have that much of a series impedance - about 100 ohms with larger capacitors can suffice.

  Chris
  Read Kurt Vonnegut, Tom Robbins, and Charles Bukowski.
  
  

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  • Re: " impedance" of the 10H choke at 120Hz - cheap-Jack 06:56:36 01/29/04 (5)
    In Reply to: impedance of the 10H choke at 120Hz posted by throbbinnut on January 28, 2004 at 08:58:05:

    Hi Chris.

    First off, the formula is for reactance X, NOT impedance (which is
    the VECTOR sumation of DC resistance R, reactance of the capacitance, Xc & reactance of the inductance XL in the circuit).

    So you mean the reactance XL of the inductance is 7.539-ohm. Strictly
    speaking, the calculated impedance of a 10H inductor should be XL + DCR, assuming the stray capacitance inside the inductor is negligible to induce additional Xc & vector shift.

    So, why 120Hz? How are you so sure that this is a full wave rectification. It could be half wave or bridge-type (double full wave) rectification.

    Back to the issue, while XL is to suppress AC rippling of the HV,
    larger the better, provided the too big henries would not 'ding' up
    overshoots from the filter caps. We must not confuse with its DC resistance which should be lower the better to reduce the undue DC voltage drop throughout the HV circuit.

    Here comes in the application of active or passive regulators to provide the voltage drop required by the load plus stablization, without which filter chokes & resistors alone can't achieve.

    Good "impedance" listening

    cheap-Jack
    Jan 29, 2004.
    
    

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    • sorry, I simplified for your benefit - throbbinnut 07:33:20 01/29/04 (4)
      In Reply to: Re: " impedance" of the 10H choke at 120Hz posted by cheap-Jack on January 29, 2004 at 06:56:36:

      This is fun! So you got me, I said impedance when I should have said reactance. So what is the impedance of an ideal inductor I wonder? Oh,that's right, the impedance of an ideal inductor is equal to its reactance.

      So would you be so kind as to calculate the impedance of a 10H choke with 50 ohms DC resistance? R theta form will be fine, or real and imaginary components, your choice. Now that you've done that, compare it to the 7.5K that is calculated using ideal inductance values.

      Seems like just guesstimating was fine and dandy. Something about orders of magnitude.

      Sorry I didn't show my work.

      So where did you get your electrical engineering degree?

      Chris
      Read Kurt Vonnegut, Tom Robbins, and Charles Bukowski.
      
      

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      • What "ideal" inductor? - cheap-Jack 07:01:45 01/30/04 (3)
        In Reply to: sorry, I simplified for your benefit posted by throbbinnut on January 29, 2004 at 07:33:20:

        Hi Chris.

        First off, please qualify your OWN meaning of "ideal" inductor?
        An inductor with purely inductance, no DC resistance & no stray capactance? Is there such an animal around??? You may as well tell us
        how to design or where to get an "ideal" amp with zero distortion &
        zero time-delay!

        Secondly, what is R "theta". R is always linear, no vector angel! My goodness! I must have missed a lot. Is there such a vector R around???
        If you want to involve the vector angle of the stray capacitance, spit it out clearly, for the sake of those less knowlegeable than you.

        Thirdly, what is "ideal" inductance? Inductance itself ia a magnitude
        qualification of an inductor or a coil, in simple language, unit 'henry'. Are you telling us an inductor comes with X "ideal" henries & Y "unideal" henries?

        IMO, it is your over"guesstimating" or confusion or what? One can get
        this basic electrical knowledge from high school. Otherwsie, I got
        to re-study my electrical engineering discipline back to college.

        WE can't read your mind right every time. Please present your lofty ideas precisely & concisely. On behalf of whoever read your posts, thank you.

        Good 'sober' thinking & listening

        C-J
        Jan 30, 2004.

        PS: I have told you the formula of calculating impedance. Did you read? Nobody is infallible. If it is an error or overlook, just admit it. No big deal. Please don't re-direct attentions. It won't bring
        you anywhere.
        
        

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        • so English is not your native language, I take it? - throbbinnut 07:40:54 01/30/04 (2)
          In Reply to: What "ideal" inductor? posted by cheap-Jack on January 30, 2004 at 07:01:45:

          

          I was referring to 2 different ways of notating complex numbers - (radius, angle) or (real, imaginary).

          Example: (1, 90deg) in (R,theta) form = (0, 1) in (real,imaginary) form.

          I thought you were familiar with that notation. My bad.

          Now, as for the impedance of a 10H inductor with 50 ohms series resistance, the answer I was looking for was (7539, <89.62deg), which is equal to (50, 7539). Most people will agree that for first order approximations, (7539, <89.62deg) can be represented by (7539, <90deg).

          So you learned all this in high school? Wow, must've been some good high school. All I learned was Ohm's Law in High School.

          As much fun as this exchange is, I feel we must call it quits. All of our arguing has boiled down to misunderstandings due to language differences.

          It's just tube amps, after all.

          See ya,
          Chris
          Read Kurt Vonnegut, Tom Robbins, and Charles Bukowski.
          
          

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          • Re: so English is not your native language, I take it? - Pär 09:08:39 01/31/04 (1)
            In Reply to: so English is not your native language, I take it? posted by throbbinnut on January 30, 2004 at 07:40:54:

            Hey hey,

            Calm down... :-D

            Don't argue over the last decimal - as long as one is right within 5% that is high quality.

            I know "cheap-jack" is a dickhead, but to argue - no matter how tight one are - is a perfect waste of time and effort...

            Where will the world end if everyone is nitpicking?

            mvh /Pär
            
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            Me fail english, thats unpossible!
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            • Your "native" English stinks - A.. H... !! - cheap-Jack 06:31:41 02/02/04 (0)
              In Reply to: Re: so English is not your native language, I take it? posted by Pär on January 31, 2004 at 09:08:39:

              So, "dickhead" is the "nature" English yuor nom teaches you. Right?
              I wanna tell her "Par" english" is so fu.k..g "unpossible" !!!!!
              
              

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