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[Beginner] Having trouble using one momentary switch to activate multiple oscillator circuits.

Discussion in 'General Electronics Discussion' started by GiuseppeG, May 22, 2020.

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  1. GiuseppeG

    GiuseppeG

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    May 22, 2020
    Hi there everyone, this is my first time on this forum! I'm a pretty big novice in this field, so I apologize beforehand. I'm currently working on a project that is 50% experimental instrument 50% niche art project. I'm making a synthesizer that has multiple oscillators per key. Ideally, when it is finished, we can get some fun out of phase and detuning that wouldn't be possible with a regular 1v/o oscillator. So what we have is four oscillators per key, two reverse avalanche, two 555 square wave. Each one of these has their own potentiometer to tune independently. Right now I have the two of the reverse avalanche circuits [I'm using this which isn't a real schematic https://www.lookmumnocomputer.com/projects#/simplest-oscillator ] I've successfully made the circuit on breadboard and perfboard and it works just as intended, with the potentiometer controlling the tuning. As soon as I attach two of these oscillators to a single momentary pushbutton [in between the 1k resistor and both the potentiometers] The oscillators start interfering with each other and effecting each others pitch and speed. With my nonexistent knowledge, I thought maybe one or two diodes would help. I tried to put em everywhere I could and had no luck. I posted this on Reddit and I got one response saying very vaguely to stick a capacitor to ground where the power splits. I tried it and all I got was one of the oscillators using that capacitors charge after the key was depressed to add some sustain to the note... so it faded out instead of stoped abruptly. I'm to the point in my experimentation that I'm about to just rig up four switches per key! I would appreciate any help. My breadboard is messy, but I can post a picture if needed. I've just been diving in to electronics lately and giving it a go... learning as I go. My background is in graphic design, currently working in video production, so I'm just genuinely trying to learn this by myself! I'm having fun though.
     
  2. Alec_t

    Alec_t

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    Jul 7, 2015
    Welcome to EP!
    Pictures of breadboards are only rarely helpful. What we need to see is a clear, logically arranged schematic, with component designators (R3, C99 for example).
     
    Harald Kapp likes this.
  3. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    Shouldn't that help you drawing a clear schematic diagram? ;)
     
  4. Audioguru

    Audioguru

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    Sep 24, 2016
    Of course the oscillators interfere with each other without using an audio mixer circuit.
    Usually an inverting opamp is used for an audio mixer circuit. Then the inputs are all completely isolated from each other.
    Here is a circuit:
     

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