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  • #16
    All of that. Look at it this way, it's the power supply that is moving the speaker. That power is "valved" through the power tubes. The preamp decides what gets through and what doesn't. So I'm not referring to any one aspect of the power supply. I'm referring to the whole thing as a system. If a power supply is weak or strong in any area that will directly translate to the sound of the amp for better or worse. I'm not trying to be vague. It's just that the whole explanation would be enormous and I don't have the room or even all the technical skills to explain it as well as it should be.
    "Take two placebos, works twice as well." Enzo

    "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

    "If you're not interested in opinions and the experience of others, why even start a thread?
    You can't just expect consent." Helmholtz

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    • #17
      Originally posted by Chuck H View Post
      All of that. Look at it this way, it's the power supply that is moving the speaker. That power is "valved" through the power tubes. The preamp decides what gets through and what doesn't. So I'm not referring to any one aspect of the power supply. I'm referring to the whole thing as a system. If a power supply is weak or strong in any area that will directly translate to the sound of the amp for better or worse. I'm not trying to be vague. It's just that the whole explanation would be enormous and I don't have the room or even all the technical skills to explain it as well as it should be.
      Thanks

      Let me narrow down the scope, I know SS vs tube rectifiers. The question I am really interested in is the size of the reservoir cap and the filter caps for screen and the preamp tubes. I know the theory of filter caps and time constant. I don't even think it matters in clean sound as you really do not draw big current. I mainly want to know the affect on the sound in cranked situation where both screen and plate draw big current.

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      • #18
        Originally posted by Alan0354 View Post
        Thanks

        Let me narrow down the scope, I know SS vs tube rectifiers. The question I am really interested in is the size of the reservoir cap and the filter caps for screen and the preamp tubes. I know the theory of filter caps and time constant. I don't even think it matters in clean sound as you really do not draw big current. I mainly want to know the affect on the sound in cranked situation where both screen and plate draw big current.
        The valve wizard has a good read on reservoir caps, screen and preamp rail caps.
        The Valve Wizard
        "If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
        Terry

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        • #19
          Contraire! You DO need fast and generous current for good clean tones. That's where the dynamics of LF really matter. And LF is what really takes current. And FWIW you CAN run a large reservoir cap with a rectifier tube. You need to use a Pi filter. But the Pi filter adds additional HV rail resistance. So my recent solution was to skip the tube rectifier and use a Pi filter prior to any taps on the rail. The resistance of the Pi filter was figured to give me about the same amount of sag as a GZ34 rectifier. BAM! Rectifier tube envelope and all the uf's I want. I used Duncan PSUD2 to run simulations and my final voltages for the actual build were accurate. All the sag and less of the flab.

          WRT a cranked up amp the larger reservoir caps still offer tighter LF and better dynamics, if that's what you want. There can be a point of diminishing returns if too much resistance is used in the rail and you can end up with an amp that can't charge the caps fast enough. The effect is sort of self regulating and the amp will suffer a loss of dynamics that lingers for a second. A pumping sort of effect. Not good. I suppose this condition could also lead to repeated inrush current conditions that may damage an amp too. Fortunately for me Duncan PSU lets me know when a time constant parameter is questionable. It also allows you to program in "stepped" loads so you can see what the likely recovery time of heavy current use will be. Of course you need to know approximately what sort of current the amp will demand under these conditions. I don't really because that would require more technical skills than I have. But my guestimates have been close enough that I haven't had any surprises yet. You should check it out.

          Download
          "Take two placebos, works twice as well." Enzo

          "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

          "If you're not interested in opinions and the experience of others, why even start a thread?
          You can't just expect consent." Helmholtz

          Comment


          • #20
            Originally posted by Chuck H View Post
            Contraire! You DO need fast and generous current for good clean tones. That's where the dynamics of LF really matter. And LF is what really takes current. And FWIW you CAN run a large reservoir cap with a rectifier tube. You need to use a Pi filter. But the Pi filter adds additional HV rail resistance. So my recent solution was to skip the tube rectifier and use a Pi filter prior to any taps on the rail. The resistance of the Pi filter was figured to give me about the same amount of sag as a GZ34 rectifier. BAM! Rectifier tube envelope and all the uf's I want. I used Duncan PSUD2 to run simulations and my final voltages for the actual build were accurate. All the sag and less of the flab.
            What is LF? Is Pi filter a series resistor between two filter cap?
            So my recent solution was to skip the tube rectifier and use a Pi filter prior to any taps on the rail. Do you mean you use SS rectifier, then cap, series resistor and cap to form a pi filter before even connect to the center tap of the output transform and the down stream tubes?

            WRT a cranked up amp the larger reservoir caps still offer tighter LF and better dynamics, if that's what you want. There can be a point of diminishing returns if too much resistance is used in the rail and you can end up with an amp that can't charge the caps fast enough. The effect is sort of self regulating and the amp will suffer a loss of dynamics that lingers for a second. A pumping sort of effect. Not good. I suppose this condition could also lead to repeated inrush current conditions that may damage an amp too. Fortunately for me Duncan PSU lets me know when a time constant parameter is questionable. It also allows you to program in "stepped" loads so you can see what the likely recovery time of heavy current use will be. Of course you need to know approximately what sort of current the amp will demand under these conditions. I don't really because that would require more technical skills than I have. But my guestimates have been close enough that I haven't had any surprises yet. You should check it out.

            Download
            Thanks for the link, I definitely check this out.

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