Wednesday, February 20, 2013

Yoa Answers Your DIY Questions!


I've been asked a few questions about my designs and synth DIY, so I'll answer:

Q: Do these work? I see a lot of schematics and graphs, but virtual isn't physical.
A: Yes, everything I have talked about works - I test them on a breadboard before posting about them. Building them virtually both makes it easier to see waveforms and schematics, and lets you spot problems before blowing up something.

Q: How do I make a nice, easy, simple bi-polar (+ and -) power supply?
A: An easy way to make your own bi-polar power supply is to use a wall-wart (aka those black boxes you plug into the wall) power adaptor that outputs twice the voltage you need (for me, since I use 9V designs, I'd get an 18V adaptor), then use this:
One thing to note is that, though virtual ground is mathematically 0V and will work in physical designs, I've never tried connecting it to a real ground, like on the wall-wart or an actual ground. It's safest to keep it like that, trust me. The capacitors are also just for safety, but may possibly cause problems. Just the resistors will suffice. Oh, and you can technically use other values, but I've found that this creates the cleanest power. 

Q: In your oscillator, you use a lowpass filter to get a saw wave. Does this really work?
A: Yes, but only in a certain frequency range. And it doesn't make a true saw wave, either. I need to figure out a better way to do this. 

Q: How do you read a schematic?
A: Sadly, there are a lot of ways to answer this because everyone uses a slightly different scheme. In general, go to Google and type in "Schematic Symbols". But, for the lazy, here's a good starting place: 

Q: I need a positive AND negative square waveform. How?
A: I had this problem after finding that the 0-9V signal of a 555 was getting oddly offset. What I use now is this (click the image if it shows up black):
I recommend a 1uF capacitor, a 1M rheostat for the upper resistor, and two 10k resistors on the bottom, if you want to make an audio oscillator. Change the capacitor to change the range. And, of course, power the opamp properly.

Q: Should I learn electronics before making stuff?
A: Yes and no. I started building knowing nearly nothing and learned on the way. I learned how to read a schematic and how to breadboard, and learned what circuits did. What I do now is use various basic circuits together to create interesting stuff. But, I do recommend you read about electronics while you build. Here are a few good resources:
Electronics Point - my preferred electronics forum.
Muff Wiggler's DIY Section - Muff Wiggler is a modular synth forum. This is their DIY section. 
Ton o' Schematics - (it's not literally called that) A ton of schematics are here, everything from guitar effects to synth stuff. Not all of it works, though that's pretty normal for free online schematics.
The Art of Electronics - This is my personal copy of The Art of Electronics by Horowitz and W. Hill. It basically is a textbook that explains all the basics of electronics, and several useful circuits. 

You'll find a LOT more stuff on teh interwebz and maybe in local bookstores and such. A good thing to do is to keep a well-organised library of schematics, ideas, pdf books, et cetera. I do. 

Q: Where do I get parts?
A: Most parts (including knobs, jacks, perfboards, and the like) can be had at your local Radioshack or other electronics store. If they don't have what you need or you don't have such a store, I prefer Mouser Electronics for parts. You can also use Futurlec, but they are VERY slow with delivery (so far it's been 5 weeks and I have yet to see a package). As for stuff like panels, power boards, special wires and such, I prefer Doepfer's excess parts. It's all professionally set to the Eurorack standard so you have less to worry about! Of course, if you are building in a larger format, there are other places to get your parts. 

Q: How do you have the time to do all of this?
A: It's a combination of having no job, most of my friends are always busy, and I'm not that interesting of a person :)

Q: If you plan to turn this into a company, why do you post all of your schematics and explain how they work?
A: Why not? I mean, I technically own all of my designs, therefore I should be able to use them however I'd like. If you think about it, I'm just saving you time. You can go online and see the PCBs of any module, and you can look at the connections and build one yourself. I'm just saving you some time.

So that's about it. Hope I answered your question, and if not keep asking! I'll probably do this again. 

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