Tube preamp scheme.

Discussion in 'Amps [BG]' started by sanyaalwaysbass, Feb 5, 2013.

  1. sanyaalwaysbass


    Sep 25, 2012
    Hello everyone! I'm in search of a good tube preamp scheme. It's assembling must not be expensive like alembic f2b or ampeg svt pro.
    I will be grateful for any
    help you can provide.
  2. majortoby


    Jul 2, 2009
    Tampa, Fl USA
    Well, first thing's first. How conversant in electronics are you? This sort of undertaking can be seriously dangerous and fruitless to the uninitiated. Just a thought.
  3. sanyaalwaysbass


    Sep 25, 2012
    sorry, i'm forget:

    >Please note, that
    it has to be easy to assemble,
    because my friend-engineer will
    be in charge of that.
  4. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    Take a look at the front end of an Ampeg B15. It's about as simple and straightforward as a pre-amp can be. If you are wanting to use this to drive a SS stereo power amp, you'll need to add a cathode follower to the output, preferably with some kind of output transformer. That should be a simple task for an engineer with a knowledge of tube electronics.
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  6. Has anybody seen an "open source" schematic for the ultimate DIY design?
  7. xk49w

    xk49w Supporting Member

    Apr 13, 2008
    I replied to your duplicate posting over in Pickups & Electronics.
  8. check out the g9 preamp
  9. Link?
  10. synaesthesia


    Apr 13, 2004
  11. ThisBass


    Aug 29, 2012
  12. The Alembic is basically a Fender preamp and tone stack, can't hardy get much simpler for a preamp.
  13. majortoby


    Jul 2, 2009
    Tampa, Fl USA
    I'm detecting english as a second language here. Where are you located? That could help us help you :)
  14. fdeck

    fdeck Supporting Member

    Mar 20, 2004
    Madison WI
    HPF Technology: Protecting the Pocket since 2007
    Are you volunteering? ;)

    A nice idea might be to show a preamp build, progressively, starting with the most basic features. A couple of gain stages with a passive tone stack in the middle is about as basic as it gets. Then you can add things like midrange, DI, etc.
  15. majortoby


    Jul 2, 2009
    Tampa, Fl USA
    I agree that starting with a very basic pre would be the way to go. At least starting out, you could probably get nice results with a couple gain stages, a SIMPLE eq, and cathode follower.

    It would not be the most versatile device ever crafted, but you would have the ability to tweak it more to your liking, and develop a better picture of where you want to take it from there.

    And you never know, a simple clean pre with minimal eq just might be your dream tone :D
  16. BAce


    Jul 31, 2012
    A single channel Alembic F2B is about as easy a tube preamp build as you will find. And they sound great. I did one a while back and I love it. It was however my 27th amplifier or preamplifier build. Mine isn't exactly stock either--D.I. out as well as the normal output, cathode follower, a few extra switches. So do some reading, look at a LOT of pictures of finished builds to get an idea of how these things are put together.
  17. I wish, but I'm not at all literate in circuit design. Speakers are my thing.

    I've seen a few point-to-point photos here on TB of units that are superbly constructed for ease of service.
    These don't have the compromises required for mass production, i.e. surface-mount, printed circuit boards, pots soldered to boards, etc, etc.

    This is not the correct forum, but I suspect somewhere there is in-depth discussion about circuit design for the ultimate bass preamp.
    My SVP-Pro schematic thread got a bit of discussion going, but it did not continue.
    Some of the smart design guys were chiming in as to why a particular circuit was good or bad, and what was required to improve it.

    I wouldn't object to paying top dollar for a well-designed custom preamp, with full schematic, that is fully serviceable (point to point) long after the maker exits the business.

    My daughter's 1985 JCM-800 is an amp like this.
  18. Passinwind

    Passinwind ......Charlie Escher Supporting Member

    What's your idea of top dollar Bruce? And how custom would it need to be?

    Personally, I don't consider turret or terminal board construction to be functionally any better or worse than good printed circuit boards -- especially if they're wired by a beginner's hands. The '85 JCM800s used a printed circuit board, BTW. '85 is right around when Marshall started doing board-mounted pots and jacks too, so your daughter's amp is quite desirable if it's the old style build.
  19. Clark Dark

    Clark Dark

    Mar 3, 2005
    If you're not into the Alembic F2B then try the Fender Dual Showman :meh:
  20. xk49w

    xk49w Supporting Member

    Apr 13, 2008
    I mistook the OP's comment to read that he considered the Alembic F2B or Ampeg SVT Pro to be an example of the "must not be expensive" type. :meh: I think you'd struggle to find a tube preamp simpler or less expensive than an F2B. Maybe with no tone controls?
  21. TBer Passinwind is one of the pre-amp guru's around here, he posts on different builds pretty frequently. Do a search on some of his stuff, then PM him.

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