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Topic: The simplest way to amplify a guitar signal (Read 857 times) previous topic - next topic


Hi everyone.
I am working about my paper for my final exams.
I am trying to create a guitar tuner with arduino but my biggest problem is how to amplify the guitar signal which is the output of the jack.
The problem is that the signal from the guitar is too small to be picked up and i can't find a way to amplify it.
I tried with a opamp with a high gain but nothing;i tried with a transistor circuit but nothing...
Can anyone show me a simple circuit which really works???

thanks a everyone and sorry for the bad english:)


Amateurs built the ark, Professionals built the Titanic


Jun 20, 2013, 11:45 pm Last Edit: Jun 20, 2013, 11:59 pm by DVDdoug Reason: 1
An electric guitar should put-out about 1V into a high impedance.  That should be enough without a preamp.  Have you measured it?

Are you using an analog input?   With the Arduino's 10-bit ADC and the default 5V reference, you'll have about 5mV resolution.

Since the guitar signal is AC and the Arduino can't accept negative voltages, you'll need to bias the signal.  For that you can use a pair of equal-value resistors (I'd use 1 or 2 megohms for a guitar) to make a voltage divider for 2.5V bias. (Put a capacitor in series with the input to isolate the DC bias from the guitar pickup.)

Then, you'll need to subtract-out (or otherwise deal with) the bias in software.


What kind of guitar is it ?
The output that you will get depends on what kind of pickup the guitar is using.
Is it an electric guitar or an acoustic guitar as if its the latter, it will use a magnetic pickup
which depending on whether its a passive or active pickup could have a low output voltage
in the millivolt range.

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