I’ve wanted to build this kind of effect for a long time. This was actually the reason I got my 4066 ICs half a year ago, when I visited my electronic components shop.
A Tremolo is an effect unit that modulates the amplitude of the guitar signal, usually in a triangular waveform. This version uses a square waveform, for a more switching, chopping kind of effect. This kind of effect can be heard in the beginning of Plant Telex by Radiohead. Tom Morello of Rage Against the Machine uses this kind of effect too, he, however, uses a “kill switch” on his guitar, which he controls manually.
More after the break…
This is a very simple and low quality circuit, whose problems can be seen in the following video. I built it in about an hour, that’s how simple it is. It is based on a simple NAND oscillator from an LED Chaser circuit that I had built maybe a year ago. Here’s the circuit diagram(proudly drawn in GIMP):
Values that I had used in my circuit:
- Supply Voltage: 5VDC
- R1 – 1MOhm
- R2 – 10KOhm
- C1 – 47uF
The idea behind the circuit is quite simple. The NAND provides a square wave pulse (and there are better places where you can understand how it works, google “NAND oscillator”) that is then hooked up to the 4066 IC. The 4066 is contains 4 analog switches, where each switch is controlled by a single input pin – as seen in the following diagram:
The 4093 NAND IC contains 4 NAND gates, so I used a free one to invert the clock signal.
I used 2 of the 4066 switches. The first one, connects the input signal + and the output signal +, while the second one connects the output signal + and the ground. One switch is controlled by the output of the oscillator, and the other is controlled by the same output, but inverted. The result is that the output signal switches between the input signal, and no signal (ground connected to +).
This is rather primitive, but that’s the whole point behind this simple project !
Here’s a short video showing my prototype and live demo of the effect (grr, I forget my entire English vocabulary when I talk):
I will be glad to hear any ideas as to how to improve the circuit. My main goals are:
- Eliminate the POP noise
- Allow higher frequencies
- Add a 4017 counter with 8 switches(representing one bar) that will allow more complex chopping
I have loads of bipolar transistors, maybe I’ll try to use them instead of the 4066…
That’s it ! Please let me know if you build it yourself !