Vox AC4C1 schematic and mod ideas

Discussion in 'Amp Tech Center' started by PurpleStrat, Feb 2, 2014.

  1. gusfinley

    gusfinley Tele-Afflicted

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    This is a great write-up. I have found that the "Custom" EQ sounds perhaps a little better in some settings (depending on what sound you are going for), but I always wire my vox amps up with the classic EQ - sometimes you just want that top boost strangeness in there.

    For those of you who have no idea what we're talking about, get Duncan's tonestack calculator and turn the Bass and Treble up to max, you'll see a huge notch filter around 500 Hz or so. I've ran an EQ into a Marshall DSL401 with the 500Hz band at minimum and it sounded very "voxish."

    Nice work, Bartimaeus!
     
  2. inuhadog

    inuhadog NEW MEMBER!

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    the bass sucker is c5. raise the value as you like.

    i want to get rid of static hum of my ac4-c1-12.
    it's very annoying when i throw a microphone on it at lower volume.
    is there anybody who had tryed up-grading power supply?
     
  3. FrankC

    FrankC TDPRI Member

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    AC4C1-Schematic.jpg
     
  4. FrankC

    FrankC TDPRI Member

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    A client brought this in for mods. Too thin he said. I swapped Treble and master VR changed the tone stack, and the input. Dropped the Master bright cap. Ordered a G10M Greenback. It's thick now. mod.jpg
     
  5. gusfinley

    gusfinley Tele-Afflicted

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    I spent some time today with my AC4C1-BL hand-wired conversion. Its sounds amazing!

    When it was stock it just needed C20 (master volume bright cap) clipped and it sounded great.
     
  6. justthomp

    justthomp TDPRI Member

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    Resurrecting this...

    Put a Hammond 125CSE in my AC4C1 the other day and now I have almost no signal at all. If I turn the gain and volume all the way up I get a signal that is about as loud as my tele unplugged, but with a level of hiss near to what having the volume all the way up regularly would. I clipped C6 and C20 at the same time (definitely those two and not others unless the PCB is mislabelled) but I don't see how either of those would be the culprit.

    Any ideas?
     
  7. justthomp

    justthomp TDPRI Member

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    Nevermind this,.. It turns out that the amp is fine. Apparently the wiring in my tele got messed up the between when I played it last and when I plugged it into the AC4. Grabbed the LP tonight as the tester and the amp is fine.

    The good news is I much prefer the tone with the new OT and C6, C20 clipped!
     
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