Portable H2 Generator - The DC Converter (Part 1)

It is been a while I am not posting anything. But now I have an opportunity to sharing of my building process of H2 Generator. This is a pre-amp design by Nelson Pass at First Watt. You can find the full schematic on firstwatt.com.

This is a fun project. I just make it a little bit serious.
As you may read directly from the original post in First Watt website, H2 generator is a 2nd harmonic generator pre-amp. This can be assume as a tube sound generator but in the solid state components. H2 will works on different type of amplifier and the result will be interesting for me to know what the tube sound really is.

The goal of this project is to make this H2 even capable to test in many audio system, then make it portable is the best possible way. It will get power supply from any DC 12 volt, which can be install on car or with common wall adapter.

To do so, I need step-up DC to DC converter circuit to feed desired H2 voltage which is 24 volt. Then this junk from the old car active cross-over network will do the job very well. I copy the switching power supply section directly put in the new board. You can make from many commercial DC step-up with the same result.

The secondary output from the coil is 30 volt then regulated by IC 7824 to make 24 volt output. It is become more cleaner DC right now.

This is how the bottom board link together. Looks complicated but in reality is not really is.

If you wondering about the original DC - DC converter schematic, this is my drawing from the junk crossover.

As the desired voltage has achieve, then I can continue to the power supply section in H2. The design using LM317 to adjust voltage before feed in to the JFET J112.

Adding more capacitor for smooth and linear DC output is an advantage.

The voltage output after the LM317 is 16 volt. The potentiometer position is at the center. It should be adjust later for proper distortion level to the audio output.

This is the end for the part 1, the part 2 will cover the main pre-amp circuit.

Disclaimer: Any statement and photos in this article are not allowed to copy or publish without written permission from the writer. Any injury or loss from following tips in this article is not under writer responsibility.