Home Forums General DIY Pedal Discussion Dr. Phybes rate LED

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  • #1905
    Jay Allman
    Participant

    So I have built several Dr. Phybes circuits and used the rate LED mod that was detailed in the old forum. However that rate LED gives only an on/off LED at the speed of the phaser. What I would like to know is if there is any way to add a rate LED that pulses rather than just on/off? Looking for something like the rate LED on the EA tremolo, Apollo tremolo, or some other phaser circuits I have seen. Thanks for any input!

    #1906
    wilkie1
    Moderator

    I believe this is what you seek:

    Rate LED Mod as posted by Tim Shelton

    Patrick Garland (words) and Schectadon (picture for Dr. Phybes

     

    1. Solder a Limiting Resistor to the POSITIVE side of the LED (Round) – on Blue LEDs I use a 3k9 Resistor

    2. Connect a wire to the Resistor, and solder the wire to 9v

    3. Connect a wire to the NEGATIVE side of the LED (Flat)

    4. Connect NEG LED wire to lug 3 of Speed Pot

     

    #1912
    Jay Allman
    Participant

    Thanks, that’s the way I have been wiring it, which works fine and gives a blinking on/off led in time with the rate.  I was just wondering if there were a way to wire up a rate led that pulsed from off, growing steadily brighter to on, the steadily darker to off?

    #1914
    wilkie1
    Moderator

    Sorry, I don’t know how to design that.

    #1915
    Barry
    Keymaster

    LEDs can be dimmed in two ways: analog and pulse-width modulation (PWM) dimming. Despite its attractive simplicity, analog dimming can be inappropriate for many applications because it loses dimming accuracy by about 25 percent+ at only 10:1 brightness levels. Pulsing is a more complicated animal.

     

    #1924
    Jay Allman
    Participant

    Thanks guys.  I was hoping there would be just a different place on the Dr. Phybes circuit that I could attach the LED to get that dimming pulse.  I will have to consider if I want to just go with the blinking rate LED or tackle the more involved animal that is the dimming pulse LED as outlined above.  Appreciate the help!

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