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Soundsamples of my new MiniAmp Project

Discussion in 'Shock Brother's DIY Amps' started by FcKw, Sep 12, 2010.

  1. FcKw

    FcKw TDPRI Member

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    Hi @all,

    I got a request for some soundsamples of my new DIY MiniAmp project at the "Amp Central Station" and so I did a short video this weekend. I It is an approximately 1.5W-2W amp with a ECC99 push-pull poweramp. Its got two 12AX7s in the preamp and provides a TMB tone-stack and a volume control. The PI is a cathodyne one. The preamp is based on the Blues Express variant of the Trainwreck Express with Vox Night Train values and some small refinements.
    Sry for my sloppy playing but it was 10AM on a saturday morning. :rolleyes:



    greets
    Patrick
     
  2. MrB14ck

    MrB14ck TDPRI Member

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    WOW :eek: - amazing sound
    I realy love it!!
    What Output transformer it using for ECC99 tube?
    Can you post schematic?
     
  3. markw51

    markw51 Tele-Afflicted

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    Great sound and nice video production too.
     
  4. rolling56

    rolling56 Friend of Leo's

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    I like it :D and best of all you built it :cool:
     
  5. Stubarber

    Stubarber Tele-Meister

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    Outstanding, and no need to apologize for your playing, either!
    So do you have it cranked there? Was your volume at "10" for the rockier bits?
    What were you using for a speaker?
     
  6. smoss469

    smoss469 Tele-Afflicted

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    Have a drink on me? Nice!
     
  7. Tarnisher

    Tarnisher Friend of Leo's

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    Sounds great! What's the speaker set up?
     
  8. gadgetfreak

    gadgetfreak Tele-Afflicted

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    Sounds were great and I enjoyed your playing as well. Do you every try and build a enclosure for these lil chassis's or do you just leave it like that, just curious. Nice work on the video production as well

    btw what kind of tele is that and also I meant to mention above how I love how you can play softly and then dig in and get that nice subtle grit.
     
  9. FcKw

    FcKw TDPRI Member

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    First of all thanks to all of you for this amazing response and all your kind words!

    As OT I used a little Hammond 125B and yes I can and will post a schematic, just have to draw it first. :D

    No, just in one very short scene it was cranked, for any reason I missed it to do some more cranked examples... the most time the volume was turned up between 1/4 to 1/3 where you can find my "sweet spot" for a Tele on this amp, you can see the settings on every scene, the controls are from left to right: Volume, Treble, Middle, Bass. It really has plenty of gain/overdrive.

    Oh yeah I forgot to write about it. The speaker is a Celestion G12-30 in a 5e3 Tweed Deluxe cabinet.

    Yeah, you've got to play some AC/DC when it comes to tube overdrive. :)

    No, these 2 mini amps I've build will be staying like that for home and recording purposes, I managed to get all the dangerous parts in the chassis and it is a solid closed chassis, its one of these enclosures that are normally used for effects units so you can only burn your fingers when you touch the tubes. I'm more the electronics guy and not so familiar with working with wood and metal. :)
    And that is a Fender "Highway One" Telecaster of the first generation, only modifications are brass saddles and a Fender Twisted Tele pickup in the neck.

    Yes absolutly, that's why I love those tube amps... :)
     
  10. kevoreilly

    kevoreilly Tele-Meister

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    Killer, I've got to do a couple of videos like that.
     
  11. FcKw

    FcKw TDPRI Member

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    That would be cool, I'm looking forward to it! :)
     
  12. mgwhit

    mgwhit Tele-Holic

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    As usual, I love your stuff. Is V2 a cathode follower or a phase inverter in this one?
     
  13. FcKw

    FcKw TDPRI Member

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    Thanks! V2 is used for a cathodyne phase inverter and for a third gain stage. Schematic will be following soon.
     
  14. mgwhit

    mgwhit Tele-Holic

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    Wow -- not what I expected! Is there any benefit to using the Cathodyne PI vs self-splitting the ECC99, or are you just using it as a distortion source?

    Can't wait to see the schematic!
     
  15. FcKw

    FcKw TDPRI Member

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    I used the cathodyne in this build over the self-splitting PP poweramp for three reasons:
    Nr. 1: I wanted to try something different to my first mini amp.
    Nr. 2: I wanted to use two 12AX7s for a different sound and overdrive behavior and to compensate the gain-loss of the tonestack, but with only three triodes used as gain-stages there was still one triode left wich asked for a cathodyne PI :D
    and Nr. 3: The PP poweramp with the PI gives you a little bit more output and clean headroom over a self-splitting PP poweramp.
     
  16. falconer

    falconer Tele-Holic

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    Incredible job! Makes me want to take out my soldering iron. ;)
     
  17. celeste

    celeste Friend of Leo's

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    PP self split triodes are really inefficient, unless the tail resistor is really large. With a tetrode or pentode you can drive the "other phase" from the screen of the driven phase and not loose to much, but with triodes, the undriven side pretty much just idles and balances current in the OT.
     
  18. FcKw

    FcKw TDPRI Member

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    So here is the schematic:

    [​IMG]

    greets
    Patrick
     
  19. mgwhit

    mgwhit Tele-Holic

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    Very cool. I was looking at a blackface Princeton schematic this morning and wondering if your pre-amp was similar. Looks like a very similar tube topology with different component values, added Middle control and no negative feedback. Nice.

    What's R24 doing, if you don't mind my asking? I thought that might be some kind of feedback, but wasn't sure.
     
  20. FcKw

    FcKw TDPRI Member

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    As I wrote in the first post these are basically the preamp values of a Vox Night Train and you're right the Princeton Reverb is another example of a similar preamp design and R24 is a feedback loop which attenuates the bass and boosts the highs. This is also taken over from the Night Trains "Bright-Mode".
     
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