I made a Deadbug style LFO bank with 555 timers. The panel has 4 lfos all with the simplest timer/clock setup, but I wired up an input into each circuits cv pin (pin5) so that if you patch the output of one LFO to the cv pin of another it will mix the triggers or “sync” them sort of. I think it’s neat, but I really don’t know what to call the effect. Anybody ever use 555 in this way? I will post a schematic after work and maybe a demo if anybody’s interested.
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It is kinda a mix of FM and PWM when you modulate pin 5 of a 555. If you modulate pin 4 (Reset) it is more like soft sync.
Pretty cool idea! 
EDIT: I cant get the google drive link to work, keep getting an error code 400.
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This demo should be easier to view. Sorry for the inconvenience. https://youtu.be/Cuyk4wo5McI?si=wGukOyCAJbaTmFwF
To get sync I just added an input jack to pin 5 of each 555 (easy to remember)
And 1uf electrolytic cap for the outputs
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I think Ive worked out how the oscillators are synching via pin 5.
See below, Oscillator 1 (OSC1) is modulating OSC2 as youve described, and When OSC 1 goes low OSC2 switches off as pin 5 is not supposed to go below about 1-2 Volts the result being the same result (Sync) as modulating pin 4 (Reset)
Now we have OSC3 being modulated at pin 5 BUT importantly via a 2k2 resistor. The effect of this resistor is to reduce the amplitude of the voltage on pin 5 which now goes from 5.5 to 8.8 volts performing frequency and pulse width modulation as expected.
A good mod would be to put a pot before pin 5 of the next 555 being modulated in the chain.
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And the JFDI accreditaion would be yours!
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I will at some point but Ive already got too many projects in development!
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This is way cool! I’ve just filled up my first rack. I just installed the last module yesterday. I made them all. Not all my designs but all made by my hands. The next rack will start soon and I intend to make these mods for another 555 LFO panel for the new rack. Thanks!
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Its very addictive isnt it?!
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NICE!! 
Looks like you could squeeze in another narrow one if you closed the 3 gaps on the bottom row.
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Yeah…the gaps…was possibly gonna shrink those gaps and make another dual vca. The dual vca is narrow enough and it is in fact on a scraped panel that broke down the middle while drilling on it. Don’t remember what it was supposed to be for originally, but it was the perfect size and I was just lazy. Sooooo, if we pretend it’s on a full sized panel, as was the original intention, we don’t have any gaps…
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