Guitar Overdrive + Sub-octaver




About: Music: my profession for over 40 years... Electronics: my beloved hobby always.

Intro: Guitar Overdrive + Sub-octaver

Guitar overdrive circuit based on CD4069 cmos IC. This digital logic IC contains 6 identical inverters composed of a complementary pair of mosfets. In this circuit they are used as analog amplifiers. Overdriving yelds a "warm" tube-like overdrive distortion sound. CD4013 is a dual D-register or flip-flop cmos IC. Here it is wired as bi-stable flip-flop and output Q is half the frequency of clock input. In music, one half frequency is equivalent to one octave below. Balance potentiometer sets the ratio between overdrive and sub-octave signals. Keep in mind that 4013 is a digital IC and will only understand a monophonic audio wave. Its output is a square wave with no envelope.

Step 1: Device Views

Step 2: PDF Download Link

click here for direct download

I made this PCB with the Heatless Toner Transfer method

Instructables - youtube

Step 3: Circuit Diagram & Details

Step 4: Balance Potentiometer Sets Ratio Between Overdrive & Sub-octave

Step 5: Drive Potentiometer Sweeps From Soft-clip to Hard Clip Distortion.

Step 6: For More Details Watch the Video. Thank You!

Step 7: Sample Soundfile Link

link to sample soundfile

only added a little delay to "sweeten"

Last minute mods: replaced R9 was 100K now is 47K. Added 470p ceramic cap in parallel with R12



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5 Discussions


1 year ago

Is this your own design? I wish you would have provided a before sound and after sound so we could hear this circuit. But nice design either way. I may have to make one and drive it to see what it can do.

4 replies

Reply 1 year ago

Hi! nothing really novel in this circuit but yes, it´s my design. I´ll include a soundfile shortly. Thanks!


Reply 1 year ago

Yes, please do a clean sound and with a gadget sound audio file. Thank you.


Reply 1 year ago

soundfile link

Only added a bit of delay.

Mods: replaced R9: was 100K now is 47K. Added 470p ceramic parallel with R12