Here’s something that I’ve been working on recently…
Tremolo is an effect or technique that involves the rapid triggering of a sound– you’ve almost certainly heard it before! When used properly, you can get great sounds out of it.
That’s the complete schematic for it (so far). I’ll try to explain how each part of the circuit works…
This circuit is simply an amplifier… It takes the input audio, and feeds it through the circuit. It’s wired up to work with audio current around 0.5 volts, the standard output of a bass or guitar. The component at the beginning is a volume control, in case the input source is already amplified… Cheap, I know. But on to the next bit!
This part uses a 555 chip, a timer circuit. In this case, it produces the rate at which the tremolo runs. A range of about 1 to 17 Hz can be achieved with this. All the way to the right you’ll see a separate input source, as well as a switch. This is so the user of the device could also add a ‘carrier’ signal, allowing them to use a different oscillator.
The left circuit acts as an amplifier, only this time for the oscillator. This is just in case the user input goes below the 5 volts that the rest of the circuit operates under. The round component all the way to the left is actually an LED, which would be used to indicate the status of the oscillator. An almost identical setup is used to amplify the final output (shown on the right).
This segment is the actual tremolo! What it does is take the input source (the ‘minus’ pin of the triangle-shaped apparatus), but amplifies it based on the oscillator (fed to the ‘plus’ pin).
As an example, the built in oscillator returns only 5 and 0 volts (5 being the operating voltage of the circuit, 0 being ground). So when the oscillator is set to high (5 volts), then the input source will be amplified to 5 volts. When at 0 volts, the input source is not amplified at all… Here’s a picture demonstrating this:
The top wave is the final output, and the bottom is the ‘carrier’ frequency… That’s all there is to it, really– the rest is just conditioning the circuit so it’ll function without adding any unwanted distortion!