This is a cool and nice project – a 3 bands Tone Control with a boost or cut of +/-20dB of Bass, Middle and Treble controls, a pure analog processing using op-amp and no digital stream. The Power supply is also pure analog PATC-SPS.

my final prototype with fiber glass casing

testing the PATC tone control along with the intended split power supply

Features :

  • designed for audio hardware starter (AHS)
  • courseware and shareware
  • pure analog process for Hifi music
  • preferred by Audiophile and Purist
  • 3 bands : Bass, Middle and Treble Control
  • 2 Separate op-Amp for the input & Tone Control
  • +/-20 dB  Boost and Cut
  • 800mVrms input /  2.2Vrms output 
  • single PCB for tone Control
  • dedicated Split Power Supply  (PATC_SPS)
  • option to add a digital tone control (PT2257 chipset)
  • funded and executed by a Filipino group of hobbyist
  • 1deBB  (1diy electronic building block)
  • bundle with the document, theories and circuit explanation


Recommended for AHS  (Audio Hardware Starter)
Definitely recommended for an Audio Hardware Starter (AHS) or a school project. Why?

This project comes with a full document of describing how the circuit works, manual assembly procedure, testing and more fun to build, hence,   this project is a crash course,  when you first experience how to solder, or practicing solderability, reading component, assemblies, testing and actual implementation.

History :

We have an educational discrete amplifier project with a group of friend from and we wanted to have a partner tone control. There were several Tone Control online and can be surfed in the internet, however, I wanted to give it a try……………… and so, the PATC (pure analog tone control) came into action. I make this project under to be funded by the DIYer’s by contributing Technically and/or donate to make the kit version. Thanks to many diyer’s from this forum

Design Stage :

I have chosen Op-Amp to be the active component over discrete Transistor, this is the passive tone control block and the active Op-Amp block :

This was the simulation with National Instrument,

Bass Boost Response at 1KHz, the upper waveform is the input signal while the lower waveform is the output signal

Bass Cut response @ 500Hz

Treble Boost response at 1KHz

Treble Cut response @ 1KHz

The mock-up before finalizing the Gerber file, I do not know much of 3D rendering at that time, and so, I make a paper mock-up PCB with actual components.

First Hand Made Prototype live testing with Audio DAC (Digital Analog Converter — the one with blue PCB and have USB interfaced) connected to a PC. Here, the PATC mainboard was powered by the PATC_SPS split power supply board – a +/-15Vdc well regulated dedicated power supply.

The final PCB that I can share with my friends — final prototype

Final Testing – the PATC mainboard with then +/-15Vdc well regulated power supply on my bench

As its purpose, it needs to be paired with the DNY40W Power Amplifier project with the team, and so, I made a simple casing design using black fiber glass

The final project appearance along with the intended Amplifier (bottom : DNY40W discrete power amplifier) – – it looks the same as in the paper design, isn’t it?

Where is the DIY Learning ?   Its hard coded into its document, I made effort to make it to be compliant to be used by AHS (Audio Hardware Starter).

Getting the necessary Document to build this project :

The files are shareware and courseware, please go to this link to download the full document. I would like to know who are interested in my hobby, kindly help to fill the form, thank you so much.

Make this Project a Better Project:

If you would like to contribute,  have comment/clarification or want to improve this project,  kindly contact me.