New build - single ended EL34 with power scaling (10w)

Discussion in 'Amps and Cabs' started by eddy999, Feb 4, 2012.

  1. eddy999

    eddy999 Member

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    Here's my latest build in progress. It is a single ended EL34 based amp for about 10w, with EF86 preamp and power scaling (VVR from Hall Amplification). I wanted to build an amp with as short a signal path as possible, and also wanted to build a single ended amp as all my others have been push-pull.

    I ended up with an EF86 preamp (as i'm fond of the EF86 after my other projects) feeding a single ended EL34. The single pentode preamp stage keeps things very simple, more so than using two triodes of a 12AX7 for instance. The signal path is pretty much as uncomplicated as possible - EF86, volume control, EL34 (no tone controls etc). I don't fancy pissing my neighbours off to get some distortion from it however so i'm adding a VVR circuit that I had knocking around from Hall Amplification to control the overall voltage levels in the amp (preamp and power). Looking forward to seeing how this little guy turns out!

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  2. eddy999

    eddy999 Member

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    Some progress:

    [​IMG]
     
  3. Paul86

    Paul86 Member

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    Cool! Very cool! Keep us posted, please.
     
  4. Fendert

    Fendert Member

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    wow This looks awesome! I want to here clips when its done!
     
  5. midnightlaundry

    midnightlaundry Member

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  6. SteelerFan88

    SteelerFan88 Member

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    Here are some pics of my little SE 5 watters. I build from scratch as well. Nice looking iron you got there BTW.... Nice and BEEFY !

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  7. crunchman

    crunchman Member

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    How about another preamp tube with push/pull pot ?? NICE !!
     
  8. SteelerFan88

    SteelerFan88 Member

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    Nah......I like the way it sounds as is. I am not much on push/pull...levers....switches...gizmos etc. To each his own I always say.
     
  9. crunchman

    crunchman Member

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    I had an amp with the pull-gain (Lexicon signature 284), very versatile.

    I guess with a single ended output stage, you get adequate pre amp gain from

    2 gain stages.Very cool amp btw, Parts cost ?? I was considering the Phaez Daisycutter

    10 in kit form, $389 w/ chassis.....not bad.
     
  10. vdoochild7

    vdoochild7 Silver Supporting Member

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    Looks like a great idea. I'd love to hear it.
     
  11. dumbell78

    dumbell78 Member

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    +1 Get some clips up if you can.

     
  12. Mattbedrock

    Mattbedrock Silver Supporting Member

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    That's some cool British goodness - an EF86 and an EL34. Classic.

    Thanks for sharing - I love a good build thread.
     
  13. eddy999

    eddy999 Member

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    Thanks for your comments. Cost so far is about $160 in parts, excluding cab/faceplate/tubes etc.

    I shouldn't need any more preamp gain stages, i'm aiming for simplicity and power stage distortion that i'll control with the vvr.
     
  14. eddy999

    eddy999 Member

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    That's a great looking little amp, especially the cab.
     
  15. eddy999

    eddy999 Member

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    Wiring progress

    [​IMG]
     
  16. GaryE

    GaryE Member

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    Very neat!Can't wait for more!
     
    Last edited: Feb 8, 2012
  17. crunchman

    crunchman Member

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    Are you using both sides of the 12ax7 ?
     
  18. eddy999

    eddy999 Member

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    I'm not using a 12AX7, it's an EF86 pentode preamp. That's why the heaters are wired to just pins 4 and 5.
     
  19. crunchman

    crunchman Member

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    Oh, I missed that part ! I'm not familiar with EF86 stuff.
     
  20. eddy999

    eddy999 Member

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    Wiring complete - just need to check it all over, and recheck the schematic/layout before starting the initial power up process.

    [​IMG]
     

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