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Tremolo Top View


EA Tremolo is designed to be very simple to use, but also very flexible and powerful effect. It works just fine with electric guitar with electromagnetic pickups, as well as with acoustic one with piezoelectric pickups. The circuit is entirely analog and adds absolutely no delay to the sound which may be caused by some digital circuits.


  • Bypass switch
  • Volume control
  • Depth control
  • Speed control
  • 9V Battery connector
  • 9V DC adaptor jack
  • 1/4” input and output jacks
  • Solid metal box which protects from outer influences
  • PCB (Printed Circuit Board) and electronic components
  • Red LED on/off indication
  • Metal box 4.92 x 3.35 x 1.57” (125x85x40 mm)

Some theory:

From mathematical point of view, the tremolo effect is a kind of low-frequency amplitude modulation applied to a certain signal. It is specified by the speed (rate) of the signal change, depth and the waveform.

The speed, or the rate of the tremolo, specifies how many times per second the signal changes or more specifically changes its depth. The typical values of the rate are between 0.5 Hz to 10 Hz.

The depth specifies how rapidly the signal changes. The depth is measured in dB (decibels) and shows how much the signal goes from quiet to full loudness. For simplicity the depth is measured in percents. 0% indicates silence, 100% - maximum loudness. The typical values of the depth in dB are from 3dB to 10dB.

The waveform indicates how the signal would sound. The natural form is sinusoidal, but there are also square, triangular and other complex forms.

Technical specifications:

The electronic components used in the EA Tremolo are of high quality and every element is checked before being placed on the PCB. The printed circuit board (PCB) if of high quality and is covered with antioxidant layers to prevent corrosion. The circuit is designed to be small and compact as well as completely functional.

The Volume, Speed and Depth features of the tremolo are controlled by three potentiometers. They have 300 degrees angle of rotation and can be used for fine control.

The volume control potentiometer adjusts the level of the output volume. The range is from 0% to 100% from the input signal. The power of the output signal to the speakers is controlled by a user’s amplifier connected by a cable from the output of the EA Tremolo to the input of the user’s amplifier. The output levels of the pedal are calculated in such manner that they are suitable for the input of the amplifiers.

The depth potentiometer controls the depth of the modulation from 4 dB to 8 dB.

The waveform is sinusoidal because of its natural form.

Power supply:

EA Tremolo uses two types of power supply. The first one is 9V DC adaptor and the other is battery, which makes it completely mobile. The circuit needs very little power to function properly (around 6 mA), so a normal battery can withstand more than 100 hours of play. When the red LED light becomes dimmer or the sound of the tremolo changes rapidly, it means that the battery has to be changed. Changing the battery is very easy, just remove the smaller lid by unscrewing the two bolts and remove the battery. Be careful not to damage the connector. After removing the old battery, take the new one and connect it to the connector. Then push the battery in the gap and then close the lid.

The size of the box is 4.92 x 3.35 x 1.57” (125x85x40 mm).

The box weight is 420 gr. without battery.

Sound quality:

The sound quality of the pedal is dependant to some extend on the power supply. Some DC power supply adaptors may provide distorted signal which may affect the sound quality. The best quality is achieved my using battery power source, because the battery gives no distortion. If the pedal is used with DC adaptor and there is noise present, try with a battery. The noise should disappear. Most of the adaptors have good quality of the output so it should not be a problem. The other source of noise might be the guitar itself. Guitars with electromagnetic pickups may add more noise than ones with piezoelectric pickups. If there is a noise without the pedal turned on, than there will be noise after it is turned on.


The supply voltage of the pedal is 9V DC, which is not dangerous to humans. You have to be careful with the adapter you are using, because the input voltage to it is much higher. DO NOT use the pedal in wet or moisture environment, because short circuits may occur. The operating temperature is from -10 oC to 50 oC (from 14 oF to 122 oF ), but the best temperature of use is around 20 oC (68 oF), because the temperature may affect the quality of the sound. Before changing the old battery with new one, check of there is leakage of the battery. It happens if the box has been held for a long time in moisture conditions or in high temperature. If the battery is covered with something which looks like rust or there is a strange smell coming out of it that means the battery is probably leaking. If that happened, DO NOT touch the battery with bare hands, use some gloves or cloth to take the battery and remove it. Clean the gap with cloth and put the new battery inside. If necessary use alcohol, not water.

Download User Manual (PDF ~280kB)

Box overview:

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