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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    The schematic is based mostly around the "Square Wave Oscillator" portion of this website, which has a handy calculator for you:http://hyperphysics.phy-astr.gsu.edu/hbase/Electro...One of the resistors is replaced with a variable resistor, allowing the frequency to change. If I recall correctly the base frequency of this design swings between about 200 Hz and 1kHz.

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    The moog input is an odd use of it, but it does have a bit of a preamp with some gain on it, but the moog output still needs to go to some kind of preamp to drive speakers or headphones.If you're plugging in powered speakers into this, you should be able to get decent volume out of it. Hope that helps!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    If I recall correctly, it's supposed to come out at "line" level, or close to it, which will require some sort of amplifier to either drive headphones or a set of speakers.(short answer is "yes"!)Glad it worked for you, I'm amazed that this project still gets hits =)

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    There would be! Essentially you'd be using the same "power" section of the circuit for both, and adding a second "Oscillator" section. I don't have a schematic for something like this, but look into a summing amplifier circuit: https://www.electronics-tutorials.ws/opamp/opamp_...With that, you take the "Oscillator Output" from both oscillator sections into two inputs of a summing amplifier, and have one output.Hope that helps!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    Hmmmm... Unfortunately it's really hard to diagnose problems from pictures of breadboards. The top problems are usually making sure that the op amp is the same, and that the pinout for the op amp is correct. You can also bypass the "output volume" stage and go straight to your speaker (what would be the "tip" output can go to the "oscillator output" wire).The different potentiometers probably shouldn't affect much, it'll change the frequency range, and should be a similar volume curve.Another one is make sure all of the ground connections are all connected together, across all of the circuits. Last thing is is the speaker powered by an external power source or battery? The circuitry won't drive a normal speaker, as it doesn't have an amplifier on its output...

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    Hmmmm... Unfortunately it's really hard to diagnose problems from pictures of breadboards. The top problems are usually making sure that the op amp is the same, and that the pinout for the op amp is correct. You can also bypass the "output volume" stage and go straight to your speaker (what would be the "tip" output can go to the "oscillator output" wire).The different potentiometers probably shouldn't affect much, it'll change the frequency range, and should be a similar volume curve.Another one is make sure all of the ground connections are all connected together, across all of the circuits. Last thing is is the speaker powered by an external power source or battery? The circuitry won't drive a normal speaker, as it doesn't have an amplifier on its output stage.Hope some of those suggestions help!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    This is awesome! Good work!

    Hi there! Thanks for the comment. It seems as if you have two separate questions which I'll answer as best I can here:1 - can you also have a triangle wave generator?In short, yes, but not through an AND or OR gate - those are digital gates, and their output is either OFF or ON, so no analog signal (being the sine wave or triangle wave in this case) would pass through them. What you would need is a summing amplifier between the "oscillator section" and the "volume and output section" in the schematics above. Here's a good tutorial on a summing amplifier: https://www.electronics-tutorials.ws/opamp/opamp_... In that example, your sine wave output could be V1, your triangle could be V2, and if you wanted to add additional oscillators, you could chain on v3, or add a fo...

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    Hi there! Thanks for the comment. It seems as if you have two separate questions which I'll answer as best I can here:1 - can you also have a triangle wave generator?In short, yes, but not through an AND or OR gate - those are digital gates, and their output is either OFF or ON, so no analog signal (being the sine wave or triangle wave in this case) would pass through them. What you would need is a summing amplifier between the "oscillator section" and the "volume and output section" in the schematics above. Here's a good tutorial on a summing amplifier: https://www.electronics-tutorials.ws/opamp/opamp_... In that example, your sine wave output could be V1, your triangle could be V2, and if you wanted to add additional oscillators, you could chain on v3, or add a fourth, fifth, etc.2 - As far as adding an ADSR envelope generator, that is going to be an incredibly complicated task well beyond the skill level of this instructable. The gist is that you'd need to have your oscillator output go through a "multiplier circuit" - in practice a VCA circuit. You'd also need a lot of complicated circuitry to generate the ADSR envelope, as well as an additional gate input to "trigger" the ADSR.In short, I'd say skip the ADSR for now - but this is a design of modular synthesis, so you can build the oscillator as is in my instructable and add in an ADSR envelope generator later on without needing to modify the original circuit!Hope that helps!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    I don't know any schematics *specifically,* but my suggestion would be to get some voltage controlled resistors and replace the "pitch" potentiometer, or put the VCR either in parallel or in series with it for various types of control. Hopefully that makes sense!Glad you got it working!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    SympanS - can't speak for KrisL38 directly, but it looks like he's got two 9v inputs (the smaller jacks on the right side of the board), and two 1/4" outputs on the top. Based on that I'd guess no CV input, as the schematic would have to be pretty heavily modified to allow for a standardized CV input to be meaningful at all.The oscillator circuitry is pretty simple and straightforward and is more aimed at the "first electronics project" type of thing as opposed to the professional synth community.Thanks for the interest though!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    Hi there! Unfortunately, I haven't gotten around to uploading the eagle file, so sorry about that! If you're starting as a student I would still recommend getting the experience of breadboarding and perfboarding before you order a custom PCB. Trust me, it'll make you appreciate the PCBs a lot more ;).As far as changing the resistor and capacitor values, the short answer is "a lot of different things would happen," as the different caps and resistors have various purposes:R2 and R4 "divide" the 9v battery signal into ±4.5v rails for the op amp, and as such their value isn't *super* important, as long as they are both the same. Lower values will drain your battery faster though.R1 serves as a current limiter through the diode, so again lower values will drain y...

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    Hi there! Unfortunately, I haven't gotten around to uploading the eagle file, so sorry about that! If you're starting as a student I would still recommend getting the experience of breadboarding and perfboarding before you order a custom PCB. Trust me, it'll make you appreciate the PCBs a lot more ;).As far as changing the resistor and capacitor values, the short answer is "a lot of different things would happen," as the different caps and resistors have various purposes:R2 and R4 "divide" the 9v battery signal into ±4.5v rails for the op amp, and as such their value isn't *super* important, as long as they are both the same. Lower values will drain your battery faster though.R1 serves as a current limiter through the diode, so again lower values will drain your battery faster. higher values will most probably dim your LED, but feel free to play around with those. The highest value of resistor with an acceptable LED brightness is your ideal.All of the resistors and capacitors in the "oscillator" section of circuitry are what actually define the frequency of the oscillator. Without getting into too much depth here, the easiest way to see how they affect things is playing around with the calculator on this website:http://hyperphysics.phy-astr.gsu.edu/hbase/Electro...R9 works with the volume potentiometer to "divide" the signal as a voltage divider. Messing around with these will just change the output volume.C2 and R11 just form an RF filter circuit, so you don't inadvertently create an antenna and radio tuner circuit from your mess of wires and have it end up in your audio signal down the chain. Changing those won't have any audible difference for you.Hope that helps, happy tinkering!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    That's awesome! Regarding the 2 9v, you should actually be able to power both of them off of a single 9v - if you make just one of the "Power Supply" section on the schematic, your +4.5v and -4.5v nodes can power both oscillators at their respective ±4.5v nodes. Hopefully that makes sense!-Darren

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    Hmmm... Cool idea. What might work is if you put something like a 10Ω resistor with one side on the ground shunt, and the other side connected to the momentary switch, with the other side of the switch connected to the node between the volume pot and the capacitor. Hopefully that makes sense in text-form.Regarding the noise - not quite sure where that might be coming from =/ It sounds like there's some sort of ground loop between this circuitry and whatever amplifier you're using. Perhaps a ground lift plug?

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    There wouldn't be any direct sonic consequences - the circuitry and the op amp would work exactly the same - the only difference is you'd be able to increase the output voltage of the oscillator; Op amp operation only allows the output to be between its "rail" voltages (in the case of the circuit in the intractable, -4.5 to 4.5 volts). If you increased it to ±10v, you'd be able to output up to those voltages.Hope that helps! Happy Synthing!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    You'd have to build some sort of "CV to resistance" conversion circuit, so in a sense, yes it's "possible" but there would unfortunately be a lot of math involved and slightly more complicated circuitry to get it to be precise to pitch and everything.

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    Could you provide some more specifics? In electronics, there's a wide range of things that could go wrong, in any number of spots. Are you breadboarding or using a perfboard? What are you hooking it up to, headphones or normal powered speakers? Did you use the exact list of parts mentioned in the instructable?

    Hmm. There's any number of things that could be going wrong - if your IC is heating up a lot, I would say it's probably due to over-voltage or mis-wiring. What voltage are you using for the power supply? Or are you using a 9v battery?Are you 100% sure that the op amp you're using is the same model (and therefore has the same pinout) as the one in the tutorial?Are you breadboarding the project first before moving to a perfboard?Go ahead and post some pictures!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    There's no crystals in these circuits, it's just the relationship between the resistors, op amp, and capacitors that causes the oscillation to occur. This oscillator build is *drastically* simpler than anything you'll see on a DAW like fruity loops, logic, pro tools, etc. The design doesn't allow for control inputs from things like LFO's, or a dual-oscillator modulation, or anything of that nature unfortunately.Like the ideas, but they're definitely a lot more complicated than this project allows for!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    Absolutely! But not "through" one another per se. You'd have to get some kind of mixer together to play them at the same time, but do some googling, circuits for mixers are definitely out there and relatively easy to implement!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    If you mean "where might parts 2, 3, etc. be?," I fully intend to [eventually] make some more instructables, but have never gotten around to it. This particular instructable I don't do much work on other than replying to comments and the occasional update.Glad you like the project!

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  • Build a Square Wave Oscillator - Part 1 of DIY Modular Synths

    Without a looooot of extra electronics, not easily. The MIDI protocol is based on "events," like "note on" and "note off," whereas something like this is analog audio and relies on continuous signals, often called "Control Voltage" or "CV" signals in the analog synthesis world. So, you'd first have to purchase or construct a MIDI to CV converter.Additionally, you'd have to alter the circuit to allow for a CV input (which I've intended to do for a while, just have never gotten around to it!), so unless you're quite familiar with analog circuit design, I'd say it's probably best to just stick to what's in here.If you've got a MIDI keyboard, I'm guessing you've got some sort of software that could almost definitely synthesize a square wave ...

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    Without a looooot of extra electronics, not easily. The MIDI protocol is based on "events," like "note on" and "note off," whereas something like this is analog audio and relies on continuous signals, often called "Control Voltage" or "CV" signals in the analog synthesis world. So, you'd first have to purchase or construct a MIDI to CV converter.Additionally, you'd have to alter the circuit to allow for a CV input (which I've intended to do for a while, just have never gotten around to it!), so unless you're quite familiar with analog circuit design, I'd say it's probably best to just stick to what's in here.If you've got a MIDI keyboard, I'm guessing you've got some sort of software that could almost definitely synthesize a square wave (I know, not the answer you were looking for, but that's part of this device being so simple, is it doesn't have a whole lot of bells and whistles).So sadly, in short, no. =/

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