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Bassline – Bass Guitar Tube Preamplifier

So far, we do not really dealt with bass guitar  effects, amplifiers. Here, in this time of change!
One of my favorite band The Beatles, inspired a new tube bass preamp creation.
The plates can hear great tunes and sounds of the XXI century it is significant. This’ 60s-edge
tone you want to give a little back. This simple, little preamplifier may be able to create a good bass sound.

The idea

Okay, what do we need? First, a simple tube preamp and a tone sections. And yet… put a little extra! Whether it is a switch which can give more prominence to the bass sound. And finally result in the power amp section. The tube 12AX7 or ECC83 should be. And we are ready to go.

Build the bass guitar preamp

As shown in a schematic diagram, not complicated circuit. The circuits are designed triodes ordinary way. Located between the two triode the tone control section. Here we must mention the little extras are what we promise you. It was built in the SW1 signal switch and capacitor C7. This will give even more powerful bass sound.

Even a small change in the circuit (well, not so little, the C8 is quite large capacitor). The C8 was originally 100nF, it was replaced with 1uF. Thus, it improved bass response with what is perceptible difference. Suggested type for a high-quality MKP capacitor. We conducted a little experiment, was left inside the 100nf and 1uf capacitor, one switch to choose between the two, and thus is connected to the output. so you can compare the two capacitor deep voice transmission. Feel free to experiment with different manufacturers and types of capacitors.

Bassline - bass guitar tube preamplifier
Bassline – tube bass guitar preamp – click to open full size

The prototype

No complicated thing. Since this is just a prototype is not ready to pcb. Simply put together a breadboard prototyping board. To try and change it if need be perfect.

And a test video:

Attention! The circuit operates at high voltages!

H&G Amplifiers shall not be responsible and disclaims all liability for any loss, liability, damage (whether direct or consequential) or expense of any nature whatsoever, which may be suffered as a result of, or which may be attributable, directly or indirectly, that you use of the circuit. During construction and use will be very careful and cautious!


  1. Adriano Alves Adriano Alves

    Hi there. First, thank you for sharing your knowledge with some enthusiasts like me… Concerning this Project I would like to know of there is necessary 6,3 V heater voltage as usually in tube circuits. Regards from Brasil. Have a great week!

    • H&G Amplifiers H&G Amplifiers

      Hi Adriano, yes necessary. Have nice day!

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