Question about syntetiser + sequencer

[sushyoshi]

Hello

Anyone got any experience with CMOS 40106 to create square waves? And what about 4017 counters to create sequencers?

Now I am trying to build this : 555 clock for the 4017 sequencer that ouputs for each 40106 input making it a square wave sound output.

I´ve been trying to make it work to get each step of the sequencer to drive a square oscilator ( 40106).
I could get it working but each step of the counter adds sound to the next one. Like this:

step 1 - drive square oscilator 1 - speaker
step 2 - still getting sound from step 1 and driving oscilator 2 - speaker
step 3 - getting all the previous sounds + driving oscilator 3 - speaker.
and so on....

What i dont seem to get it working is to get each sound only of each step. I have tried 1n4148 diodes at the end each output oscilator but they cut the signal and all i hear is a metronome.
I have tried resistors in series but they end up mixing each step signal.
I dont understand the diodes should work preventing current to go back to the input.

Anyone got any advice or could share some knowledge on the 40106 and 4017 synth and sequencer?

[wavley]

Try this, I'm pretty sure he has the schematic for his sequencer in the pdf.

http://www.clockworkrobot.com/synth/index.htm

[slacker]

Something like this will turn on one 40106 oscillator at a time. When the output of the 4017 is low the diode between the 4017 output and the 40106 input pulls the input low which stops the oscillator. When the 4017 output is high, it's like the diode isn't there and the oscillator runs.  



EDIT: Changed the drawing the original thing wouldn't work.

[sushyoshi]

Thanks for the asnwers. I saw the pdf but it was nothing  Andiferent of i was hoping , that circuit used a motor.

As for your sugestion on the picture, i cant really understand it, why are the ouputs of the 40106 connected again to the input of the 40106? Anyway ive tried that and got nothing ( no sound at all).

Here is what i´ve been doing and working but still with the overlapsing outputs of each step:



Sorry forgot the caps

I just did that with each step. If i change the ouput R with a diode i can only get pluck sounds on the speaker. Also without the transistor i could not get enough signal.

Any advise?

[slacker]

The 40106 on the end acts like a buffer and mixer for the signals, if you add a large capacitor to the end of it, it will drive a small speaker or you can send the output of that to where ever else you want. It should work fine, the diodes on the inputs to stop the oscillators is a common trick, are you sure the 4017 is working properly?

[sushyoshi]

So i should connect the outputs of the 40106 to a new input of the 40106? Something like pin 5 ( input #3 of 40106) and the apply a caps in series for the speaker?
I am gonna try again tomorrow.
The 4017 seems to be working because i can get it to sequence LEDs. The problem is to drive the oscilators.
Also the +V connected to the outputs and final input i cant really understand it? Is it to power the 40106 inputs and regulate the voltage with the pots? I though i could use the signal that eas coming from the 4017 alone.

Sorry for my newbness i´m still trying to learn these stuff.

[slacker]

So i should connect the outputs of the 40106 to a new input of the 40106? Something like pin 5 ( input #3 of 40106) and the apply a caps in series for the speaker?

Yeah that will work, this should be able to drive a small speaker like the "beeper" in a PC. I probably will not work very well with larger speakers. To drive bigger speaker you can use something like an LM386.

Also the +V connected to the outputs and final input i cant really understand it? I

The diodes and the resistor to V+ make the 40106 gate act like a NAND gate, this lets the signal through from which ever oscillator is running. Have a look here for more information http://www.musicfromouterspace.com/analogsynth/mmlogic.html

[sushyoshi]

Ok I´ve tried it and it works  . But i need a amp for it. Is there any other way so that i can drive it directly through a speaker even without the 386? Because when i was playing with the 40106 and made the square oscilator with a pot to varie the frequency i could get great sound without an amp, driving directly to a 8ohm speaker and had great control over the frequency. Why cant i get that same sound and frequecy control when combined with a sequencer?