Make Your Own Tremolo Effects Pedal

In this instructable I will show you how to make your own tremolo effects pedal. Really what the pedal is doing is switching the guitar's signal on and off sequentially, ( a DC-square wave generated from a 555 CMOS osclilator pulsates the power to a lm386 audio amplifier amplifying the signal from your guitar.) making that cool effect that we have heard in so many songs to date. For this project you should have a basic idea of soldering and circuits.

Step 1: Materials

As far as tools go you will need:

1.) Soldering Iron

2.) Solder- Make sure that you have rosin core solder, acid core does not work on electronics.

3.) Multimeter (Optional, but very handy)
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Twenty dollars spent at your local Radioshack will get you all of the parts you need for the pedal:

1.) Resistors:     470ohms x 3 (Yellow-Violet-Brown)
                              4.7K x 1 (Yellow-Violet-Red)

2.) Potentiometers:   100K x 1 (the small type that solders onto the board)
                                       1M x1     (the big type that you attach the knob to)

3.) Integrated Circuits:  LM386 Audio Amplifier
                                          555 Timer

4.) Transistors:     PNP Transistor x 1

5.) Capacitors:      10uf Polarized x 2
                                 .1uf Ceramic x 1
                                 220uf Polarized x 1

6.) LEDs:      Green LED x1
                        Red LED x2

7.) Connectors:       Female Guitar Jack x 2
                                   9v Battery Clip x 1

8.) PCB:                Any standard perfboard should do, I used one about the size of a credit card that I                                   bought at Radioshack.

Step 2: The Schematic

This schematic provides the bones of the circuit, but feel free to modify it to your hearts content! R1 controls the volume of the input signal, and R2 controls the rate of the pulses. R3 controls the duration of the pulses. C2 increases the internal gain of the LM386 from 20 to 200. Q1 inverts the -9v signal from the 555 to a +9v signal that oscillates the guitar signal. I didn't add a power switch, but it would be a good addition.  If you have any questions about the design, feel free to comment!

Step 3: Building the Circuit

Before you actually solder, you should test the circuit on a breadboard. What I did was break the circuit down into chunks and test each one (the timer, the transistor, and the audio amplifier). I'm sorry I don't have any photos from the build process, but I wasn't expecting to make an instructable on the project until after I built it.

Step 4: Thank's for Viewing!

I hope this project was of use to you, again if you have any questions, feel free to comment.

Comments

[dmarinov]

What is the transistor ?

[CuriousMotor]

2N3906

[Brucela]

Try a 2n3906 for the transistor.
I would try the circuit with a flashlight bulb and a photo resistor.

[Cg8282]

Hey anyone know specifically what type of transistor is needed? Just went to electronics shop and guy said “pnp” wasn’t specific enough. I know next to nothing. Planning to ask an electronics buff buddy for some help but haven’t got around to it

[mark8883]

Hey, I am new to electronics. I went to buy capacitors to make this tremolo, but they come in different voltages (16v, 20v). How do you determine which voltage to select?

[CarlM101]

i know i'm 6 years late on this, but the rule with capacitors is that you can never go wrong using a cap with a breakdown voltage higher than the supply voltage (or whatever voltage it will encounter in that circuit)
since this project is powered by a 9V battery, a cap with a 16V rating, or anything higher, is fine. you could use a cap rated at 200 volts, and it wouldn't make a difference.
what you don't want to do is use a cap with a lower voltage rating than the supply voltage, or it will burn out.
personally, i wouldn't trust a 10V cap in a 9V circuit, because it is so close that it might eventually break down.
when i salvage caps from old televisions and stuff, i don't keep anything below 16V, just so i know the re-used caps will be reliable for small battery-powered projects.

[JuanN17]

So i built it and i can hear the signal running through the pedal but the signal is extremely distorted, accompanied by a tick corresponding with the tremolo rate. Mmmh

[Uexdrukl]

Also, what is the max pulse frequency this circuit can produce?

[Uexdrukl]

I want to build one of these using a universal CV pedal to control the speed. Is that possible?

[guitarpicker7]

just a thot- the 386 is not required.

The 555 can easily drive an LED (depending on the LED, add a 100-1K current limiting resistor in series with the LED) Use clear expoxy to glue the LED to an LDR (Light Dependent Resistor - photo resistor) To vary the depth, add a 250K-500K potentiometer in series with the LDR.

One major advantage of using an LED is that potential circuit noise is separated from the signal path. Be sure to use a light-proof, metal housing. The LDR can be fooled by outside light and the metal housing will help shield from outside electrical noise.

The instrument signal is bridged across the LDR/pot bridge. The effect can be switched on/off with a switch in the 555s battery circuit. You can leave the LED/pot bridge in the circuit or add a footswitch to bypass it.

You will be limited to the 555 waveform, but it's a useful effect, especially if you add the potentiometer to vary the depth.

Experiment with different color LEDs- LDR are more or less sensitive to various color ranges.

having some fun now!
-charley

[rcosentino]

You can also change the waveform with a diode and a pot to duty cycle between 0-99%.

[Txdude]

Hello there and thank you for your instructable. I was wondering if you know of a way to also add another pot to control another part of the frequency? Like the wet and dryness. Also is there a way to clean the single up when its in a higher gain? Will adding a higher k resistor between 1 and 8 change and vary that?

[tlakbir]

what if I want to keep the gain low and use another amplifier? can I use another Lm386? if I do so should I controle the gain or the master. I'm working on this project and there is too mush distortion, I'm thinking to reamplify but I don't know how: https://www.instructables.com/file/F4THFYGGDT4GHE7

https://www.instructables.com/id/Make-a-Sweet-Portable-Guitar-Amp/

Hope you can help me: here is my e-mail if you want: [e-mail]

[Txdude]

hey thee have you figured out your problem? let me know, I might be able to help

[666sebas999]

How do you control de Depth?

[Eman34]

Do you happen to know what type of transistor would work, by any chance?

[Eman34]

Hey there. I just made this pedal but it's making a thumping percussive sound that sounds in tune with the pulse rate. Is there anyway to fix this? What might I have done wrong?

[spel3o]

That sounds about right, unfortunately. This is a rough design which can be improved on to remove that signal. I'm guessing that a major improvement that can be made would be using a transistor to switch the signal coming out of the 386, instead of turning it on and off (this most likely causes the pop). I had the same problem with mine, it worked though.

[IronWill]

Mixed Nuts!

[Trike Lover]

One easy way to add an "automatic" power switch is to use a 1/4" jack on the input with an integral switched leg. Sometimes the only switched jacks available are 1/4" stereo jacks but it doesn't matter - just wire tip and sleeve for your guitar input.

The easiest way to add the power switch function is to insert the switched connection in the jack in the negative lead from your battery to the board. (assuming you're not using a wall wart). Then, when you plug in a guitar, the battery negative terminal is connected to the circuit and it powers up. Pull the input plug and it shuts the circuit power off. This isn't my idea - I've seen it documented in about 2 dozen stompbox schematics, but it's sure handy for saving batteries. I think it's also standard in Boss pedals, among others.