DIY tube amp power supply

Discussion in 'The Projects Forum' started by frenchie29, Dec 28, 2009.

  1. frenchie29

    Thread Starter Active Member

    Nov 28, 2008
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    Last edited: Dec 28, 2009
  2. SgtWookie

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    Where is the schematic?

    It is not clear from the Ebay listing exactly what is required - except they recommend a 150W transformer. I don't know why they show 18v-0v-18v and 24v-0v-24v and 9v-0v as well. It may be due to the heater requirements. The schematic will tell the tale.
     
  3. frenchie29

    Thread Starter Active Member

    Nov 28, 2008
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    I just posted it Might gonna have to save it and use the magnifier glass it's at the top right
     
  4. SgtWookie

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    The 1st image is just too fuzzy to see. Can you scan it at a higher resolution, and post it in .png format instead of .jpg?
     
  5. frenchie29

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    Nov 28, 2008
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    Here's an update

    [​IMG]
     
  6. Wendy

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    Mar 24, 2008
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    From the eBay ad. I'm still not sure what it needs.

    power supply :AC 18V-0V 0V-18V ,(main power:AC 24V -0V 0V-24V) , AC 9V -0V transformer > 150 VA (W) is recommend
     
  7. frenchie29

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    Nov 28, 2008
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    I think I need to split the voltage in 3
    18v, 24v and 9v

    [​IMG]
     
  8. SgtWookie

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    Well, the 18VAC in seems to be feeding the plate voltage supply for the tube/valve, while the 24v supply is being used for + and - rails for the IC.

    I can't make out what the transistor is doing; the schematic is just too fuzzy. I guess you scanned it into .jpg format and then converted it to .png format? That doesn't work, I'm afraid.

    If you have to scan it in .jpg format, you're going to have to use a much higher resolution; like perhaps 150 DPI.
     
  9. frenchie29

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    Nov 28, 2008
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    I scanned at 300dpi but I am not sure what the original format of my scanner is So how could I manage to split all that voltage accross? Do I have to build a power supply for it or I can buy one and modufy it? I'll try to re-scan it again


    EDIT; The file is fine on my computer, I think photobucket compress the file when I upload it. can we send files here to PM??

    I scanned the file at 1000dpi
    PNJ is about 82MB
    JPEG around 21MB

    Ièll post it tomorrow I think it will take a while to upload.
     
    Last edited: Dec 28, 2009
  10. SgtWookie

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    It looks like it has the supply built in; but you need to connect a transformer (or transformers) that have the correct voltage and power rating in order to get it to work properly.

    It looks like they're adding the 18vac to the 24vac to get the plate voltage. That would give you in the neighborhood of roughly 52v. I don't know what your tube needs, though. I have an old RCA Receiving Tube Manual that I bought in 1970, but it doesn't have a listing for any of those tubes.
     
  11. frenchie29

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    Nov 28, 2008
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    Could I just use one tranformer and split to the 3 locations?

    The way I see it is 24V power supply step down to 18 and step down to 9v

    Have they make a mistake? I think it should be DC and not AC
     
    Last edited: Dec 28, 2009
  12. SgtWookie

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    OK, those image files are WAY too large to be uploaded here.

    See if you can scan at a lower resolution. Somewhere between 100DPI and 150DPI should be ok.
     
  13. frenchie29

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    Nov 28, 2008
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    Photobucket really compressed the files it went from 22mb to 175kb you guys know of a hosting site wheer they don't compress files after uploading?
     
  14. SgtWookie

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    You can use the "Go Advanced" button under the message text box, and then "Manage Attachments" to attach your images, right to the forum.

    Note that there is a size limit; it varies depending on the type of file.

    .png and .jpg files can be up to 293kb.
     
  15. frenchie29

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    Nov 28, 2008
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    Let's try this one

    lastscan.jpg
     
  16. kubeek

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    you can try some free webhosting and post it there. The picture needs to have at least double size, so that we can see the details. Also try to save it as a .png to get the best quality.
     
  17. Wendy

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    Mar 24, 2008
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    We have a web hosting as part of the AAC site, it's called Albums. It will automatically adjust the size of the picture, unlike attachments.

    You can find it looking at your profile.
     
  18. SgtWookie

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    Well, we don't want it to be resized. That's what the problem has been so far.

    Too much detail is getting lost.

    The last scan (lastscan.jpg) was 34kb in size. You can go up to about 290kb in size.
     
  19. frenchie29

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    Nov 28, 2008
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  20. Audioguru

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    Dec 20, 2007
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    The LM4780 Amplifier IC is an excellent stereo amplifier.
    The vacuum tube will just add even harmonics distortion and heat anything nearby.
     
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