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Thread: My first build, need help. Vox AC4

  1. #1
    Junior Member
    Join Date
    Jun 2013

    My first build, need help. Vox AC4


    Long story short, i bought a Laney VC15 that has some parts missing (it's been bought at an auction and was messed with, 2 pcb's are missing) and i want to use it as my project amp. I first wanted to build an 18W but the transformer (225-0-225) is not "hot" enough for the 18 watt so i resorted to building (trying to) the vox AC4, namely this: voxac4aa1.jpg .

    I re-did the layout to fit the VC15 chassis and ended up with this: amp-project-ac4-001.jpg

    My questions are:

    1. how do i connect the input..and to where? i'm a little lost
    2. right after the main 225v secondaries, those are diodes , right? if so, which kind?
    3. for resistors i am gonna use 0.4W unless otherwise noted but what voltage should the capacitors be?
    4. Regarding the transformer, it's a Laney 6094 and after a very long search i managed to find the specs (laney is very secretive about this). I found some of the specs from tubeampdoctor but they didn't mention the voltages for the secondaries. In the attached PDF document on page three you will find the specs for the 6094 transformer and it is 225V-20v-0v-20v-225v and then another 2 wires which have 6.3v and 6.3v BUT on the tubeampdoctor page ( ) it says that the two 6.3v wires are actually 6.3V and 0V. And also on the tubeampdoctor page it says that they are GRAY and indeed my transformer has two gray wires. On the attached PDF document it says that the two 6.3V wires are red..which they are not on mine. So, which one is it?! i am really confused.

    laney 6094 information.pdf

    Thanks you!

  2. #2
    Senior Member JHow's Avatar
    Join Date
    Oct 2009
    St Johns, FL
    1) Pin 9 is the grid of the EF86, that's where the input goes - oh, and since I didn't see the input resistors on the layout I'm assuming you plan to hang them on the jack (?)
    2) 1n4007 ought to work
    3) I would use 1/2 watt, except as noted on schematic
    4) If you only have two wires on the heater secondary (i.e., no center tap) then you probably have 6.3VAC across the two, which is what you want. You can (carefully) measure the secondaries to confirm AC voltages if you are unsure of the exact transformer specs. But first, use your continuity tester to suss out which leads or lugs are part of the same winding.

  3. #3
    Junior Member
    Join Date
    Apr 2017
    Have you thought about putting different voice controls (triode-pentode channel, dirt or clean)? It would sure be an interesting project

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