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This is my first Instructable and my first attempt at such a large electronics project. I designed the circuit from scratch and I am making it available to all so anyone interested can build their own. I have called it the Morphatron. I will not say it is a piece of cake, but I have done most of the hard work for you, and either way it is very much worth it, because this machine can accomplish amazing things.... too bad I am so close to the deadline, I was unable to make a decent demo video.
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Signing UpStep 1Design and schematics
The first thing we need is a circuit design, which I am posting as a series of images. I designed it from scratch, although I did investigate as many vocoder schematics I could get my hands on. I focused on using easily obtainable components that are inexpensive, and I tried to keep the circuit as simple as possible without sacrificing functionality.
A vocoder basically has two inputs and one output. The first input is the program (usually a connected to a microphone) and the second input receives a carrier signal (usually a keyboard). The program signal is then fed to an analysis section, which extracts the spectral information from the sound and applies it to the carrier signal. This vocoder will analise the signal on 14 bands, but the design can easily be modified to include more channels, or actually fewer (if you are in a hurry).
First, we must have input amplifiers for each of the two inputs. Then, we must build each channel, and finally mix all the channels. These are the three main blocks of the circuit. All the 14 analysis channels are identical, except for the values of the capacitors (I purposely designed it this way to make it easier to build).
Each channel in the analysis section consists of two identical band pass filters. The first receives the program signal which then goes into an envelope follower. The output of the envelope follower then controlls an VCA (voltage controlled amplifier) which amplifies the carrier signal coming in through the other band pass filter.
The next step contains a parts list, however, I will tell you right away that ALL the op amps in the circuit are TL074. So all the components you will need are the TL074's, resistors, condensers (capacitors), and NPN transistors (2N2222). I am trying to keep it simple. Also, you will obviously need wires, connectors, pots, jacks, and some material to put the whole thing in (I used plywood, MDF, and acrylic for the casing.
This circuit also requires a bipolar power supply (+/- 10-15 volts). I pulled out the power supply from a damaged old computer, which is bipolar, I used the +12v, ground, and -12v from this power supply (they are standardly marked yellow, black, and blue respectively in a computer power supply). Using an existing power supply will save you a lot of time and money.
In this step you should download and study the schematics just to get acquainted with the project.
A vocoder basically has two inputs and one output. The first input is the program (usually a connected to a microphone) and the second input receives a carrier signal (usually a keyboard). The program signal is then fed to an analysis section, which extracts the spectral information from the sound and applies it to the carrier signal. This vocoder will analise the signal on 14 bands, but the design can easily be modified to include more channels, or actually fewer (if you are in a hurry).
First, we must have input amplifiers for each of the two inputs. Then, we must build each channel, and finally mix all the channels. These are the three main blocks of the circuit. All the 14 analysis channels are identical, except for the values of the capacitors (I purposely designed it this way to make it easier to build).
Each channel in the analysis section consists of two identical band pass filters. The first receives the program signal which then goes into an envelope follower. The output of the envelope follower then controlls an VCA (voltage controlled amplifier) which amplifies the carrier signal coming in through the other band pass filter.
The next step contains a parts list, however, I will tell you right away that ALL the op amps in the circuit are TL074. So all the components you will need are the TL074's, resistors, condensers (capacitors), and NPN transistors (2N2222). I am trying to keep it simple. Also, you will obviously need wires, connectors, pots, jacks, and some material to put the whole thing in (I used plywood, MDF, and acrylic for the casing.
This circuit also requires a bipolar power supply (+/- 10-15 volts). I pulled out the power supply from a damaged old computer, which is bipolar, I used the +12v, ground, and -12v from this power supply (they are standardly marked yellow, black, and blue respectively in a computer power supply). Using an existing power supply will save you a lot of time and money.
In this step you should download and study the schematics just to get acquainted with the project.
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Thanks
All I have is a logic prob, multimeter and (if I can fix it) function generator.
Thanks
If you can get OTAs they are the easiest way to accomplish the VCA part.
I suppose I'm a tad confused as to the layout of the modules overall.
http://sim.okawa-denshi.jp/en/OPtazyuBakeisan.htm
Also, if you plan to build this please check out bitrex comments on the first step, as he suggests a better VCA (or use OTAs) for better sound.
How can I achieve that?
In the "Output mixer" image:
Can I just combine all the channels on 1 wire, then insert that wire into the minus of a TL074 (or maybe TL072), like with the mono-out, with a 10K resistor going back from the output?
If this is the case I would need 112x instead of 14x...(14x8), unless I've read something wrong, which I'm also good for.
Cheers
Cheers.
You don't have to put all these jacks, and just joint all Filter's Input with all Input Stage's output.
sorry my bad english...
BACON!
http://www.cadsoftusa.com/
Done right I wouldn't be surprised that this circuit couldn't be done on the free demo copy. Really the demo limits make me design better boards! There are some tutorials online that should help you get up to speed on the program.
But I was just reading online that if I dump some hydrochloric acid into my etchant it may work better. That, and I've always wanted to do photo-resist anyways.
Maybe if I think about it I'll do some Eagle files of this? It is not hard to do.