Wiring LED to flash with mod rate (plus showing off my new trem pedal build)

Discussion in 'Burnt Fingers DIY Effects' started by Tom Freeman, Aug 2, 2016.

  1. Tom Freeman

    Tom Freeman TDPRI Member

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    I've been on a roll with pedals lately. Over the past month or so, I've used vero layouts I've found online to build a couple modified fuzz faces, a tube screamer with a bass control, and a clone of the 4 knob Keeley compressor. My latest build (if you don't count the ram's head big muff/colorsound overdriver dual effect I'm working on now) has been a slightly modified copy of the Jordan Vico Vibe. It's a cool little tremolo, and I had been wanting to try it for months since I saw a feature on how to build one in PGS Tone Report months ago.

    Anyway, I finally put it together, and it sounds pretty cool. It won't be replacing my ehx stereo pulsar, as I love that pedal, but the vico vibe has a great vintage style trem, and from not many components too. Naturally though, I wanted to see how far I could improve it. I changed some caps and resistors around to increase the range of the rate pot, so now this thing can get nice and slow or fast and stuttery. As soon I get the parts in, I may add an internal boost circuit to compensate for the (very slight) output drop, and also rework the depth control so more of the pot's range is usable.

    One last thing I want to do (inspired by my aforementioned pulsar pedal) is rewire the led so that when the effect is on, it flashes in time with the modulation. This is a mod I may also want to implement on future pedals as well. Unfortunately, I've been having a hard time finding instructions - google only turns up a few results from forum threads that deal with specific effects, and the instructions don't seem helpful. Can anyone here chime in on how I might do this mod and apply it to most modulation pedals? Thanks

    Here's my build, just before I installed the board:
     

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  2. RLee77

    RLee77 Friend of Leo's

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    I'd need to see the schematic to determine the easiest way to drive the led. It will likely need another transistor, or a darlington pair, to avoid loading the oscillator.
     
  3. NotAnotherHobby

    NotAnotherHobby Tele-Afflicted

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    +1
     
  4. Armo

    Armo Tele-Holic

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    Looks like a cut down EA trem. Might be able to rig up something along the lines of that. jordan-vico-vibe.jpg EATAudioPath.png EAtremolo.png
     
  5. NotAnotherHobby

    NotAnotherHobby Tele-Afflicted

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    My comments relate to the last schematic.

    Without looking a bunch of stuff up, It looks like the tremolo is using the 120K resistor, 68K resistor, and 250K pot so that the output waveform is within the linear range of Q2. My thought is to tap the connection between the 120K resistor and the 250K pot, take that out to the gate of another J201 FET, connect the source of this FET to the positive side of the power line, and the drain to the positive side of the LED. Then connect the negative side of the LED to a 2.2K resistor, which then connects to ground.

    You could probably do something similar with the second schematic, except the resistors are R10 and R11 and the FET is Q3.

    Anyone agree? Disagree?
     
  6. RLee77

    RLee77 Friend of Leo's

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    The last schematic already has an led as part of the osc. load, so it already has what you want. The last schematic is also the one that looks the most reliable and well-designed. The first schematic should be avoided, as I highly doubt it even works (if it somehow does, the sound quality I would guess is pretty bad). The in/out running to an open collector is not good. It will also put a dc signal on the line, which will give you some awful thumps in your amp.
     
  7. NotAnotherHobby

    NotAnotherHobby Tele-Afflicted

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    Wow, have I ever got Tunnel-vision. I didn't even see that.
     
  8. Tom Freeman

    Tom Freeman TDPRI Member

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    Sorry I haven't replied for a long time (I've been extremely busy with a number of things). I can't find a schematic for the build, but here is a vero layout from http://tagboardeffects.blogspot.ca/2012/04/jordan-vico-vibe.html that is similar to the one I used - it's the same circuit as what I built from the tone report issue I mentioned. I appreciate the input given on those schematics for the EA trem, hopefully I can apply them to the Jordan with no issues!

    Changing the subject, I recently added a boost circuit (the EHX LPB-1) to the output of the board. I kinda stole the idea from the Fulltone trem. Not only does it act as an overall volume control that can compensate for volume loss, but it can also push the front end of an amp while the trem is modulating. It makes for a really cool swampy vibe, with tons of mojo! Plus, if I just need a simple boost without the trem, I can just dial the rate and depth to zero. It may actually knock my Pulsar off my board after all!
     

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    Last edited: Aug 18, 2016
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