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.
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:
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!
Hi Adriano, yes necessary. Have nice day!
Thank you for the answer!
i have a few questions i am new with tube amps but what power supply(i live in south africa the voltage is 220 with 50 hz) do i use and how do i buld it on the scimatic you say it requires 150v but not the current or the wattege is it dc if you look at the tube whireing pins there is a common cathode should the power supply be connected to the common cathode as well and how much power i have heard the ecc83 is a high gain tube if i want a little more clean bass tone what tubes whould you recommend
Hi Chad
The power supply can be a traditional transformer or semiconductor-based circuit.
Some common examples are:
https://www.valvewizard.co.uk/index.html
https://education.lenardaudio.com/en/14_valve_amps_6.html
https://diyaudioprojects.com/Technical/Tube-Power-Supplies/
In the video ( https://www.youtube.com/watch?v=55G_bIzPJjY ) the 150v voltage is produced by a simple MC34063 based circuit.
This is known as a “nixie power supply”, you can make it yourself or buy it from popular e-commerce sites. Here’s a very similar example using a MAX1771 circuit: https://www.electronics-lab.com/project/hv-nixie-dc-dc-switching-power-supply/ (not advertising).
All GND markings in the circuit are the negative pole of the power supply.
The power of the tube in this circuit is less than 0.5W. So you will need an amplifier circuit if you want more power.
An Electro-Harmonix 12AX7 tube can be heard in the video.
( https://shop.ehx.com/item/12ax7eh/ ) This can be safely replaced with ECC83 or 7025 type tubes, whichever you like and sounds good. It is recommended to try several types. 🙂
During the preparation and operation of the circuit, be extremely attentive and careful, 150V dangerous voltage.