Running several 555 Control voltages from one source

Dr. K · Joined: Jan 15, 2020 Posts: 52 Location: wisconsin

I've been trying to work out how to drive 2 of 3 different 555 control voltages from the same sourece. From the same sequencer, or as in the attached, from the same modulating frequency in a dub siren.

The dub siren circuit is the upper part--their is a LM741 stage between the modulator and oscillator.

It seems like you could drive several 555 CVs, simply by running each through it's own LM741 buffer stage (and a pot, if wanted).

If I split the output of the first stage into 3, all 3 should be at the same voltage. But I'm assuming the reason the op-amp stage is in there is to isolate the 2 circuits, and provide a current source.

Is my thinking on that correct? I think it would be interesting to run a couple of oscillators, which would be perfectly synched with the siren effect.

I'm sorry for all the dumb questions lately. When I started building, I just wanted to find schematics and wire up whatever the device was. As I'm revisiting this project, it was clear if I really understood the cirucuits I would be able to have a lot more freedom.

siren with 741s.png

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my proposed modification on the bottom, circled in red

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