A few months ago I built myself a cigarbox guitar. I built all myself, including the pickup and I have wired it with a volume potentiometer and a jack output.

It works well but I have to use a pedal to amplify the sound before pluging it into the final amplifier.


simulate this circuit – Schematic created using CircuitLab

What I want to do is to remove this pedal and to plug only to the final amplifier. How should I proceed? Will simply adding a 9V battery to the circuit do the trick?

Ultimately, I would like to do is to include the amp directy into my guitar. To do so, do I need any other component than a speaker?

Thanks a lot for your advice!

  • 1
    \$\begingroup\$ You haven't supplied a value for your pot, R1 in your diag. If this is too low, it will load the pickup, resulting in a lower output and loss of sound quality. It should be at least 250k, maybe 500k or 1M, logarithmic. \$\endgroup\$
    – peterG
    Nov 22 '17 at 12:59
  • \$\begingroup\$ Hi peterG, yes it's a 500k log pot \$\endgroup\$
    – aName
    Nov 22 '17 at 15:25

This is called a pre-amp. Which is really just an amplifier, but is uses to boost a very low level from a Mic or pickup to standard levels that an amp expects. They can be built using a simple transistor circuit, or use an opamp circuit or fancier multistage ones.

Your pickup may have gain or amplification control on it too. You could ditch the pot and control the volume at the amp, as the pot is the opposite of an amp, it's cutting the audio down.

If your adding the amp into the guitar, then you may choose an amp that has a pre-amp stage built in.

  • \$\begingroup\$ Thank you for your answer! Could adding a battery before the output be considered as a pre-amp or shoul I build a real transistor amp? \$\endgroup\$
    – aName
    Nov 22 '17 at 10:26
  • \$\begingroup\$ No, a battery before the output is just a battery before the output. An amplifier is not the same as a battery. \$\endgroup\$
    – Dampmaskin
    Nov 22 '17 at 12:03
  • \$\begingroup\$ You will need a battery for any pre-amp you build. And a 9V is typically used for guitar pre-amps anyway. A simple one can be just a transistor some resistors and a battery so your 1/3rd there. \$\endgroup\$
    – Passerby
    Nov 22 '17 at 14:02

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