mxr univibe mods?

Discussion in 'Burnt Fingers DIY Effects' started by tele_savales, Apr 6, 2020.

  1. tele_savales

    tele_savales Tele-Holic

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    I picked one about 6 months ago, and I'm sure most people here know that the speed knob doesn't do anything for almost the first half of it's sweep. I've never modded a pedal before, any tweaks to make the thing semi-useful? I seem to have a lot of time on my hands lately. Thanks!
     
  2. sirbergersworth

    sirbergersworth Tele-Holic

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    You would need to access the pot to tell us the taper of the speed pot. Then you may be able to swap it out with a different taper to alter the sweep.
     
  3. MilwMark

    MilwMark Doctor of Teleocity Ad Free Member

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    I’ve owned two and that’s not what I recall.
     
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  4. tele_savales

    tele_savales Tele-Holic

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    What do I do, just look at the code on the pot or measure it w a multimeter?
     
  5. tele_savales

    tele_savales Tele-Holic

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    The level and depth are 10k and 100k linear. I’m not sure what the speed pot is.
     

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  6. nathan5782

    nathan5782 TDPRI Member

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    You could use a multimeter to check the middle and either of the outside legs of the pot to get a measurement. I found a schematic of the Dunlop UV-1 which is an older unit that still uses a bulb and it has the Speed as 10kC, Intensity 47kA, Volume 10kB.
     
  7. tele_savales

    tele_savales Tele-Holic

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    Yeah this one doesn’t have legs per se, and also I was asked to get the taper by sirbergersworth. The depth pot is only 50k which is interesting. I a-b’d next to a 50k audio pot I happened to have handy and I can’t really tell the difference in the taper. 8A320580-49F7-4B9C-BA13-0871383CA82D.jpeg 6A4CF2D8-398B-4FCF-B818-C1F6263B9BEA.jpeg No legs! These are the connections on the back of the board
     
  8. sirbergersworth

    sirbergersworth Tele-Holic

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    I can assume that the speed pot is the one with its own little daughter board?
     
  9. nathan5782

    nathan5782 TDPRI Member

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    If you look at that pot from the side with the LED that red board attached to it you might be able to test from there. I have the same pedal but never opened it up. The MXR phase 90 uses a reverse taper pot for the speed control and I suspect this one as well since I’ve seen a couple of diagrams earlier which one had a concentric pot it was reverse tapered 10k or 100k I forgot and the Dunlop I posted earlier 10kC which I think the C indicates reverse.
     
    Last edited: Apr 8, 2020
  10. tele_savales

    tele_savales Tele-Holic

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    That’s right.
     
  11. tele_savales

    tele_savales Tele-Holic

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    Yeah I think C means “anti-log”. Aren’t concentric pots the stacked ones?
    At any rate I’ll try to get some measurements off the back of that little board.
     
  12. Fretting out

    Fretting out Friend of Leo's

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    Is the only issue that it is slow acting does it go from slow to fast like it should?

    I have the Jimi univibe and it does slow fast and everything in between, I haven’t noticed this, I’m gonna have to check it again
     
  13. nathan5782

    nathan5782 TDPRI Member

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    Yeah it’s a double pot, there was a univibe clone from mad bean pedals and it is also 100k dual reverse
     
  14. tele_savales

    tele_savales Tele-Holic

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    Yeah it works. It just does nothing for the first 1/3 of the sweep. I’ve read that it’s an issue, I bought it anyway, mostly because of the price. I like the way it sounds, but there’s got to be a fix.
     
  15. tele_savales

    tele_savales Tele-Holic

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    Well it looks like the speed pot is 10k
     
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