My Minipulse VCO upgrade

[dbanner]

So I modified my original Minipulse to coincide with the Rev D specs and I'm in the process of building up a VCO add-on board. I'm tapping the circuit at the first integrator output (TP4) to drive the VCO control voltage. Chopping the output of the second integrator to ground using a CD4066 switch, then unto the audio output. A second switch of the C4066 is configured as an oscillator to provide a " normal" audio which can be toggled instead of the VCO. So you can have an option of normal audio or VCO with the flip of a switch.
I'll post the circuit, please give your comments.
I've included the ltspice file.

[dbanner]

I know my ltspice circuit is a bit under drawn. Don't really care about that.

I'll be needing to select a value for C1 to get the range/response just right for the TP4 voltage. A 47k trimmer on non inverting leg of opamp2 (note there is a mislabeled resistor there) adjusts the base frequency of the VCO.

[6666]

How does it sound.

[surfdetector]

Yes, it would be great to hear the actual sound of your modification if you could post a short video.
Cheers

[dbanner]

Finally got around to working on this project again. The circuit is just about ready for testing.
Just need to run all the connecting wires and begin to experiment with tweaking the circuit for optimum performance. I have a few LM387 chips in the junkbox, thinking of using this chip to drive a speaker, may need a separate power supply. We'll see.

[surfdetector]

Looking forward to hearing the results.
Cheers

[dbanner]

Just some thoughts, output of dflop the way it is configured is half of the input. 0 volts logic low to +5 volts logic high. Bilateral gate Vdd +5 volts, Vss ground.

Supply for CD4013 is 3-18volts. I use +5 volts Vdd, Vss ground. Tl062 use bipolar power supply +5/-5 volts.
Just trying to get the correct power supply connections sorted out.
MPP battery positive is ground(0 volts).

[dbanner]

I'm just about to connect the wires from the daughter board to the main circuit.
Hopefully no magic smoke today.

[6666]

I'm just about to connect the wires from the daughter board to the main circuit.
Hopefully no magic smoke today.

Good luck

[Xtrem]

So I modified my original Minipulse to coincide with the Rev D specs and I'm in the process of building up a VCO add-on board. I'm tapping the circuit at the first integrator output (TP4) to drive the VCO control voltage. Chopping the output of the second integrator to ground using a CD4066 switch, then unto the audio output. A second switch of the C4066 is configured as an oscillator to provide a " normal" audio which can be toggled instead of the VCO. So you can have an option of normal audio or VCO with the flip of a switch.
I'll post the circuit, please give your comments.
I've included the ltspice file.

This is a very nice VCO , its working perfect , but i think its better to use the VCO , as standard tone.
and the 4066 only for select between VCO and standard.





but you are using the other 2 switches fo sampling, let it so .

[surfdetector]

I'm just about to connect the wires from the daughter board to the main circuit.
Hopefully no magic smoke today.

How did this turn out? No smoke I hope.

[Vadim18]

I'm just about to connect the wires from the daughter board to the main circuit.
Hopefully no magic smoke today.

Nice circuit! Guaranteed 50% duty cycle output
Awaiting for audio record)

If i am right the is little optimisation possible if modulate tone through flip-flop "CLR" input.
Also an excessive current can go through CD4066 switch since 74hc74 work in push-pull mode, what if exclude U6 and put instead D6 diode?

[Nightryder]

I'm just about to connect the wires from the daughter board to the main circuit.
Hopefully no magic smoke today.

Hello dbanner,
Did you get any encouraging results? I'm interested because I've got sick of the 555 growl! Very sick to the point where I'm thinking to use a car horn