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DIY-12AU7-Tube-Preamplifier.jpg

Gio sent in a link to this interesting preamp. The builder was able to make the preamp with parts on hand. I’m not sure I would have the tubes, but the rest of the parts are fairly common. [Thanks Gio]

I was pleased with how well it turned out, at 30 bucks it looks pretty professional with the solid gold plated jacks on the black case. A neat feature I added later on is the ability to adjust the brightness of the front LED. The yellow LED is to indicate that the tube filaments are active.

More about DIY 12AU7 tube preamplifier

Marc de Vinck

I’m currently working full time as the Dexter F. Baker Professor of Practice in Creativity in the Masters of Engineering in Technical Entrepreneurship Program at Lehigh University. I’m also an avid product designer, kit maker, author, father, tinkerer, and member of the MAKE Technical Advisory board.


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Comments

  1. Aud1073cH says:

    Cool- Looks like it is meant to be a phono preamp for the stereo, but I’ve been looking for a simple preamp for a guitar amp project. I think this will work.

    the 12A_7 line of tubes are out there, and very popular. (like the 12AX7, 12AU7, 12AT7, etc.)
    While it may be difficult to find the rare vintage NOS German tubes, it is easy enough to go to your local Guitar Center and get a GrooveTubes tube. I wouldn’t put them in a nice vintage amplifier, but for beginning DIY they are O.K.

    For better tubes, there are some online stores dedicated to delivering vintage, tested NOS tubes. (Google: vacuum tubes)

    (Did anyone mention that this project uses high voltage? 100V)

  2. Kevin says:

    I wish they’d make something like this, with a USB or Firewire out. :D

    THAT would be a great guitar preamp for a computer. ;)

    I am halfway joking. I am not sure how USB would be with tubes. Or would it just make it redundant.