Doubleplusbass (Kick drum by Juanito Moore)

His version based on the Thomas Henry BD++

My Doubleplusbass module is a dedicated kick drum with TEN knobs. Some of the component values need to be tweaked, as evidenced by this video, and my mixer may be clipping the waveform, adding some harmonics.

It’s a triangle-core kick drum, with a waveshaper that can take the signal to a sine wave, and beyond into a saturated sine and then the wave folds back on itself.
The decay has been decoupled from the pitch sweep, so the pitch sweep can be very sharp even with long decay times.
The pitch control response is exponential, so you can tune the kick more easily to that exact pitch, even if that pitch is very low.
There’s a CV input that can theoretically get a 1 volt per octave response with the CV attenuator knob carefully adjusted.
There’s an envelope signal available that can swing between about 10V and ground. There’s an attenuvertor on that control, which winds up basically moving the voltage offset from around ground up to about 10V, with the envelope signal fading out at about 5V, and then becoming inverted to go between an offset of 10V (to make your VCAs open up) and swinging down to ground (to make your VCAs close down). Good for sidechain.

schematic :

good quality here :


hey !

This is the last version of juanito he have post on a Facebook DIY group.

He have mentionned this too :
“I forgot the 1nf capacitor in the feedback path of the CV managing opamp. It should go between the output and the inverting input of the opamp, right by the two PNP transistors and the 4.7k resistor”.

So I suppose that the 1nf cap should go here ??

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It’s there in the EasyEDA schematic:


which however has the transistors NPN instead of PNP… ???

And the hand drawn one says “Oct 2012 version”. Typo I guess?


thank you so I was right :slight_smile:
No idea for the transistors, that look strange but I think it does work. Maybe I test it today if I have time…

yes the date is wrong, he have inverting the number… back in the past doc ! ahah

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Yes it would be nice to clarify the PNP / NPN change
which one is really the right one (surely the last one , or a mistake ?)
we are waiting for your news :slight_smile:

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again a fresh version of the doubleplusbass circuit, this time I hope this will be the last modification of juanito… hihihi

The output socket with the volume pot is the last op amp on the right with the 10K pot attached to it.

(I haven’t tested it yet)

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