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Multi-tapped power transformer secondary for dc voltage steps?

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  • Multi-tapped power transformer secondary for dc voltage steps?

    I really want this power transformer really bad... EDCOR - TBPWR-HV2-120

    It has many taps on the secondary so I could get a bunch of power supply reference points if I had plenty of filter caps and resistors right? Like if I wanted to use them for screen supplies and direct coupling etc. It also has two independant secondaries so I could make two floating supplies for circlotron. 94 bucks would be worth it I think if it did all that, but is 300ma enough? Thanks

  • #2
    how would the bias track the B+? There's sure to be a creative method.
    A circlotron? That's cool.

    Comment


    • #3
      300mA enough for what?

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      • #4
        Well, it's enough to electrocute 6 people, but not nearly enough to start a diesel locomotive. I think you need to specify your project more tightly.

        My favourite PT in my collection is one from an old Yaesu FT560 ham rig that made 300W with TV sweep tubes. It has 16A of heater windings and about 6 independent high voltage windings, and it cost me a lot less than $95.
        "Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"

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        • #5
          Voltages are on the high side. The lowest tap is 350-0-350, that's about 500V with a cap input filter. 450-0-450 will give about 630V. That equates to a high impedance OT. Might work nice for a Hammond 1650R.
          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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          • #6
            Thanks for the replies! Sorry I was a little vague, my project is an improved bigger and better stereo guitar amp that I could also use for my hifi, so the 300 ma would have to be for both channels. This would only be 150ma per channel and seems kinda small though I guess it depends on what circuit it is used for but I would like to build a power supply in a largish chassis as a test bed for some different tube amp ideas I have for possible guitar amp potential. Im a little confused as to how the 300ma rating applies to this, say if I use only the 375 taps for instance and leave the other taps disconnected then do I still only get 300ma or is it 300ma at 900 volts and more if I use lesser voltage tap?


            Really all I need is dual center tapped secondary windings, if you guys know of a cheaper transformer that would be great.

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            • #7
              Originally posted by Austin View Post
              ...my project is an improved bigger and better stereo guitar amp ...Really all I need is dual center tapped secondary windings...
              Hi Austin.
              Do you realize that you don't need a dual power supply for your stereo amp? Just checking.
              Tom

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              • #8
                Originally posted by Tom Phillips View Post
                Hi Austin.
                Do you realize that you don't need a dual power supply for your stereo amp? Just checking.
                Tom
                Yes thank you, I realy want to experiment with the circlotron type and this needs at least two sepparate floating power supplies. I saw one somewhere with four even..

                I think this will work and give me a bunch of rails to choose from and play with but it will need 20 expensive power filter caps:

                Click image for larger version

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ID:	825380 Would this work?

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                • #9
                  It's probably cheaper and simpler to build a single high voltage supply and regulate the high voltage down, either linearly or in steps, as needed. This also avoids the issues of switching setups and zillions of power filter caps. If one is scared of the sound resulting from regulated power supplies, it's easy to dumb them down by putting series resistances after the regulated voltage to introduce any amount of sag needed.

                  Regulation can be on the primary - as the variac enthusiasts know - or on the secondary, either in the AC (phase control) or DC sections. Especially for choosing from and playing with, an electronically variable power supply is going to be more useful, based on my experiences. Whenever I did something that was switched between a number of positions, the position I wound up wanting was dead in the middle between two of the fixed selections.
                  Amazing!! Who would ever have guessed that someone who villified the evil rich people would begin happily accepting their millions in speaking fees!

                  Oh, wait! That sounds familiar, somehow.

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                  • #10
                    Originally posted by Austin View Post
                    I think this will work and give me a bunch of rails to choose from and play with but it will need 20 expensive power filter caps:

                    [ATTACH=CONFIG]19115[/ATTACH] Would this work?
                    No. No no no no no. NO!
                    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 !

                    Comment


                    • #11
                      Originally posted by loudthud View Post
                      No. No no no no no. NO!
                      Could you elaborate a little bit why you think this won't work to help me to understand? I realize it's impractical to actually build this because the amount of caps would take up too much space. Also this transformer has taps that are spaced too close together, ideally it would be evenly spaced steps to be the most useful. Thanks

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                      • #12
                        I built one of these (not fully understanding it!) variable HV regulator by PDX area audiophile Gary Pimm.
                        The Swenson Regulator
                        for about $20 and it handles +600vdc and 0.5A nicely, its NOT a Low Drop Out (LDO) regulator as the Vin has to be +50v more than Vout!
                        The MOSFETs used are impossible to find but many substitutes are easily available.

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