If ever you want to build your own guitar amplifier, here’s the first thing you need to build. This is because guitar preamp are not usually sold as a kit unlike amplifiers. Guitar preamp are actually simple and usually consist of 2 stage, first – gain stage which amplifies the signal coming from the guitar and second – the filter stage which boost or cut frequencies that is determined by the user. Some preamp also includes effects such as distortion and reverb as the most common.
About the Circuit
The circuit uses the most common op-amp TL072. You can also use any general purpose op-amp such as NE5532 and the likes.
Distortion effect can be achieved by increasing the gain. If you want more heavy distortion effect, you can bypass or decrease value of R7 and increase value of R5. You can also experiment on the value of C4, C5, and C6 for tone response. For more bass, increase C5 value. C6 sets the mid frequency and C4 sets treble frequency.
PCB Design
The PCB design is included on a separate post. Sorry I didn’t noticed that I already have the same post before:
Simulation Model
As usual I used simetrix to simulate my circuits. It is yours for free as long as you don’t use it for commercial use.
Download:
You can download the files on my download page here: