Replacing a 7555 chip with a TLC555

DIY STUFF
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Hi! I’ve been lurking on this forum for a few months as I’m building my modular synth.

But now I’ve finally stumbled upon a question that I can’t quite find the answer to:

I’m currently working on a Yusynth 7555 ADSR. Unfortunately, I can’t find any 7555 chips in my country (Netherlands) for a decent price. There’s Reichelt of course, but I’m not gonna pay €6.95 to have €2 worth of components delivered.

I still have a few spare TLC555s left from a VCO-555 build. Would it be okay for me to use those instead? Do I need to change any components if I do (resistor values etc.)?

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Both are CMOS so that’s favorable.

https://forum.allaboutcircuits.com/threads/7555-vs-555.46821/ :

A 7555 might replace a TLC555, but even then there are differences between the two CMOS chips. For one thing the TLC is rated up to 2Mhz.

So if you want to run your ADSR at 2 MHz…

If I were doing it I’d try it on a breadboard first. But if that’s not possible, I would guess it’d work. Worst that happens, if you use DIP sockets, is you have a module you can’t use until you can find a 7555 for it.

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Go for it, it will work!

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Thanks guys! I think I’m just gonna try it and see. It’ll be a while until I have time to finish this one, but if it works out I will give an update. Meanwhile, I’ll order some 7555s from AliExpress, like the dirty cheapskate I am.

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The r/c values might be recalculated to lower the frequency in the 556… I’ll get my coat!