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Tuesday, July 2, 2019

Nocenteli Magnalous Lunevibe

Stumbled across this design by Nocenteli on FSB and thought it was cool, so here you go. Mashup of the Tremulous Lune LFO and the audio path from the Magnavibe with a toggle to switch between tremolo and vibrato mode. I ended up putting the Fine control internally as a trimmer for 2 reasons: 1) In my experience with this kind of LFO it's not all that necessary, and 2) I miscounted the number of pots in this when I started layout it out and was too far in to start over. 😂 You can always wire it off-board if you prefer. Should fit nicely in a 1590B.

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21 comments:

  1. MAtixJuly 2, 2019 at 5:06 PM

    hey i have some questions about the circuit. 1. Wich kind of LDR do u pref? 2. Is a Fine Trim Pot like a normal Trim pot? 3. What kind of LED do u use? 4. What is LFO -?

    ReplyDelete
    Replies
    1. AnonymousJuly 2, 2019 at 6:52 PM

      Here's my take on your questions:

      Questions 1 and 3 really go together...
      The LED/LDR unit can be had in several different forms. In old Fender amps, you have a neon bulb and an LDR wrapped up together (some call it a "roach" because it's a black thingie with what looks like four legs sticking out).
      - You can make your own with an LED and an LDR covered up with heat-shrink tubing.
      - You can buy a "Vactrol" unit that is ready made. I think the VTL5C3 is the original spec for the Tremulus Lune. I've used a CLM6000 with good results (and much cheaper than the Vactrol).
      - Check out this link and others for further discussion (and pictures to help you along if you go DIY with it):

      https://www.diystompboxes.com/smfforum/index.php?topic=95063.0

      Question 2:
      "Fine" is just describing what the trim potentiometer is doing. It's a normal 1K trim pot used for fine adjustment.

      Question 4:
      Wikipedia says "Low-frequency oscillation (LFO) is an electronic frequency which is usually below 20 Hz and creates a rhythmic pulse or sweep. This pulse or sweep is often used to modulate synthesizers, delay lines and other audio equipment in order to create effects used in the production of electronic music."

      That's not a bad description at all. Nice and to-the-point.

      For us, the LFO is going to set the rate for either the tremolo or vibrato effect. Which takes us back to that little LED/LDR gizmo. The LED blinks on and off, which is picked up by the LDR (Light Dependent Resistor). Consider it the groovy heartbeat of this pedal.

      Delete
    2. AnonymousJuly 2, 2019 at 7:00 PM

      One more thing...
      If you go to a place like Smallbear Electronics, you'll find the LED/LDR units posted as "Photocouplers".

      http://smallbear-electronics.mybigcommerce.com/photocouplers-1/

      Delete
  2. MAtixJuly 3, 2019 at 2:22 AM

    Ok thx for the answers. But what i connect to the LFO- connection and the LED +? Just a Normal LED? Is this Forechecking the rating? Or something different?

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    Replies
    1. shimanekoJuly 3, 2019 at 7:24 AM

      It's just a typo of LED-.

      Delete
    2. AnonymousJuly 3, 2019 at 9:26 AM

      Aha... I did not look close enough to see the typo.

      Yeah, that LED would just be the pedal's indicator light.

      Keep that LED's light completely isolated from the LED/LDR. You don't want the LDR picking up other light and messing up your signal. That's the main reason why we heat-shrink the LED/LDR unit together and seal it up tight.

      Delete
    3. shimanekoJuly 4, 2019 at 4:29 AM

      Oh, sorry. I was wrong. It is not a typo. + and - are both LFO-LED's.

      Delete
  3. bjb8593July 6, 2019 at 11:52 AM

    Is this in the transfer library? I can't seem to find it.

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    Replies
    1. Effects LayoutsJuly 7, 2019 at 1:40 PM

      It's in the Nocentelli folder (forgot to upload it)

      Delete
  4. bjb8593July 24, 2019 at 10:10 PM

    I just built this and it's not working. After looking at the schematic, it seems that the op-amp is not connected right in your layout. There are numerous components that are not connected to the right pins.

    Is there something I'm missing?

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    Replies
    1. bjb8593July 24, 2019 at 10:55 PM

      Wait, never mind. I’m an idiot. The op amp appears to be set up correctly, just differently. There must be something wrong with my build then. Hopefully I can get it sorted soon so we can get this bad boy verified.

      Delete
  5. bjb8593July 29, 2019 at 10:29 PM

    Ok. Finally had time to look over my build and I found the tiniest of shorts between lug 1 of the fine trimmer and lug 1 of the smooth pot. With that cleared up, it works beautifully!

    This one's verified!

    ReplyDelete
    Replies
    1. Effects LayoutsJuly 30, 2019 at 9:55 AM

      Glad you got it sorted and thanks for verifying!

      Delete
  6. Ricco SeixasOctober 16, 2019 at 9:12 PM

    This comment has been removed by the author.

    ReplyDelete
  7. Ricco SeixasOctober 16, 2019 at 9:17 PM

    not finding the mpsa18 transistor in my region, could you tell which transistor you can replace?

    ReplyDelete
    Replies
    1. Effects LayoutsOctober 16, 2019 at 10:40 PM

      Anything in the medium to higher hFE range should work. 2N5089, BC550C, etc

      Delete
  8. Ricco SeixasOctober 17, 2019 at 2:33 PM

    My project does not work, try the bc550 and have clean sound, no effect, or led does not flash, review everything, the pcb and components that are correct, but did not find the defect.

    ReplyDelete
  9. Arthur GrinyukDecember 2, 2019 at 3:01 AM

    I build this project, but it not work. Signal is clean, no effect and very loud. I used 2n5089 transistor and red 5mm led with LDR.

    ReplyDelete
  10. Jun dSeptember 18, 2020 at 2:47 AM

    Im going to build this thing and lets see what comes... more power elect enthusiast!

    ReplyDelete
  11. yussssJanuary 25, 2021 at 9:59 AM

    i built this and it worked, but it seems that the tremolo mode has lower output volume than vibrato mode. how to fix that?

    ReplyDelete
  12. Jun dJanuary 19, 2023 at 4:18 AM

    Same problem with yussss low volume in trem mode

    ReplyDelete