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Thread: vacuum tube smsp

  1. #11
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    Quote Originally Posted by eonscom View Post
    The current image smps is rectified to about 315v and is used as the B + voltage of the tube amplifier
    HER 508 4 diodes are used by bridge rectification.

    Applied Trans: ETD49
    Primary: 0.85mm X 1 - 40 TURN
    Secondary: 0.32mm X 3 - 86 TURN : 315 V

    When applied to the above specifications, the output waveform has a lot of ringing and noise.

    I am making a new transformer to apply the center tap method.

    Excellent -SMPS Transfomer Tool Data
    Attachment 6896
    Probe the primary winding. and see if the ringing is present at the primary. If it is there then you have to put a 470pf cap in series with a 3 watt 47 ohm resistor across the primary to suppress spikes and ringing.

    The pictures you posted of the tool data is too small to see it. Take picture with mobile or camera of computer screen and upload that.

    The primary of the transformer turns seems a little too much. I do not know your switching frequency and also the core material. Please give the details and I will help you out with your calculation.

    1 core material
    2 switching frequency
    3 input ac voltage at your house
    4 heater voltage and current
    5 Max plate DC voltage
    6 Bias maximum DC voltage

  2. #12
    1 core material

    -I do not know the exact specifications.
    But size is the same (etd49)


    2 switching frequency

    - 50kHz (variable) 30~80Khz

    3 input ac voltage at your house

    AC 215 V

    4 heater voltage and current

    300B : 5V 1.5A X 2EA : #18 WIRE 2TURN (6.7V Down by resistance)
    6SN7 : 6.3V 0.5A X 2EA : #18 WIRE 2 TURN

    50KHz AC DIRECT HEATING

    5 Max plate DC voltage

    MAX : 420V

    6 Bias maximum DC voltage

    MAX : 90V
    Last edited by eonscom; 03-14-2019 at 06:03 AM.

  3. #13
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    Hi Eonscom, I have made some calculations for you. As for the core material I chose N27 which is not so high permeability as the core you are using is not known.

    Here are the results

    Note 1)
    Wire size is 0.5mm This wire can handle the frequency of 60Khz. If you make thicker wire it will be in vain as the current tend to travel on the outer skin at high frequencies and the extra thickness will not be used. However you can use multiple wires together (twisted or side by side) In your case 3 wires by 0.5mm for the primary. Choose the best fit for a single layer. Either 3 wires side by side or 3 wires twisted together.

    Note 2)
    See if you can sandwich the secondary windings between the primary. Make half primary turns then secondary turns then half primary on top. Leave the heater windings for last on the very top. That is on top of the last primary winding. the heater windings are not so important.

    Note 3)
    Try to cover the whole bobin with each layer of winding. Leave 3mm margin space at the ends of the bobbin for safety. Use mylar tape this tape is high temperature and very thin. Use 3 layer of this tape to isolate the primary winding from the secondary. Use one layer of tape between each secondary winding layer so that you can see better what you are doing.

    Note 4)
    The voltages used are made such as the amplitude of the rectified and smoothed voltage will rise to the peak. If you notice the 2nd picture you will see what Mean. Please also note that the voltage will sag down with load as the smps is not regulated.

    Switching frequency 60Khz

    Primary turns 22 turns (3 wires X 0.5mm)

    Plate secondary voltage turns 65. (0.5mm x 1) ( peak voltage 427v at 215vac input)

    bluetooth aux 15-0-15 3+3 turns (0.5mm X 1) use 2 wires together and start from center tap. put ends on each side on pins.

    Bias voltage 13 turns (0.3 x1) Peak voltage 85v at 215vac input

    Heater voltage 2 turns (6.3v) 0.5mm X 1

    Heater voltage 2 turns (5v) 0.5 mm X 2
    Attached Files Attached Files

  4. #14
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    Hi Eonscom,
    One last note if you want to make adjustment just calculate that you have 7 volts per turn. 155v / 22 turns pri =7v per turn

  5. #15
    Thank you for your quick reply.
    The above specs were first attempted and have problems.
    Currently in production
    The problem is trying to apply the center tap method rather than the bridge rectification method

    Primary: (0.45x5) x 22 turn
    Secondary: # 18wirre 1 turn: Normal output waveform (6.73V)
    It is confirmed to be normal for testing

    There is no problem in applying 420V winding to 80 turns
    Further winding of 80turn will cause the coil to heat up even though there is no load
    test: # 18 Wire 1turn: Output Waveform Distortion (5.8V)

    160 turn.jpg
    160-1 turn.jpg
    Last edited by eonscom; 03-14-2019 at 02:45 PM.

  6. #16
    Re-upload your photo
    SMPS wave.pdf
    Attached Files Attached Files
    Last edited by eonscom; 03-14-2019 at 03:24 PM.

  7. #17
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    Quote Originally Posted by eonscom View Post
    Thank you for your quick reply.
    The above specs were first attempted and have problems.
    Currently in production
    The problem is trying to apply the center tap method rather than the bridge rectification method

    Primary: (0.45x5) x 22 turn
    Secondary: # 18wirre 1 turn: Normal output waveform (6.73V)
    It is confirmed to be normal for testing

    There is no problem in applying 420V winding to 80 turns
    Further winding of 80turn will cause the coil to heat up even though there is no load
    test: # 18 Wire 1turn: Output Waveform Distortion (5.8V)

    160 turn.jpg
    160-1 turn.jpg
    Regarding rectification well the bridge requires one winding while center tap requires two windings.

    One tip for you if you want to make a center tap winding.
    wind two wires at the same time. You start at the center tap. you finish with two wires each wire will be a separate winding.
    This method will help to have balance windings with equal voltages.

    I do not recommend that you make center tap winding for the high voltage side, It is the way you are winding it. Leave margin space at the ends like 4mm on each side and put a layer of tape between each layer of winding. Do not use masking tape it is not good for this work.

    Remember that square wave tend to have spikes and easily breaks insulation at high voltage.

    The distortion in the waveform is intermittent and not constant. try to twist the ends of the one turn loop and measure again

  8. #18
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    Quote Originally Posted by eonscom View Post
    Re-upload your photo
    SMPS wave.pdf
    May I ask where are you going to take the sample voltage for the regulation of the output voltage?
    I see you opted yes for regulation in Excellent IT software

    Remember that the software is suggesting the inductor value. This value will grow with minimum current for each winding. the lower the higher the inductance. If the plate voltage has a constant load then it will be right to put the right current in the software. Please note that if you are not regulating the output you do not need the inductor or it could be very small.

    The snubber resistor you are using is too high. Try like 100 ohms at least, or lower. It could be down to 10 ohms

    read this article about snubber. download the pdf.

    http://www.diysmps.com/forums/entry....gate-resistors

  9. #19
    I tried it. However, when I switched on, the protective 100W bulb turned on because of the overcurrent.
    I have wound several windings, but more than 400v (only 64 turn) is not a problem with single windings.
    If you turn 128 times in center tap mode, the coil is very hot even if there is no load.

  10. #20
    I've tried a few, but the best way is
    The windings are divided into two areas.
    Attached Files Attached Files

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