CV GATE keyboard -- Keys contact de bouncing needed?

alanwilder81 · Joined: Sep 03, 2016 Posts: 310 Location: italy

Dear folks,

I built the cv gate keyboard shown below, schemo found in the Yves's blog archive.
Although it does work (outputs CV and GATE as expected), i keep getting a note shift on key press, and most often on key release.
Almost always it's a sharp pitch drop.

In my setup im using momentary switches of varying quality.
The best ones minimize the pitch shift (often unnoticeable), but the bug is still there.
In the red square it's the RC filter debounce section, which cant seem to do much at all.
Is the rough switches contact bouncing the culprit, in first place (as i may assume) , causing a make-break make break contact, hence feeding the sample and hold a dirty signal?
And would the circuit benefit with further debouncing?

I've seen tons of methods. 555 debouncer, flip flop, schmitt trigger.
Just curious to hear your opinion about this .

cheers ! Wink

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gabbagabi · Posted: Sat Nov 03, 2018 3:37 pm Post subject:

ma che cazzo hai fatto Smile

You are back!
hope you are fine!
party time!

must be destiny, the first real house party tonight in this forgotten place - and you are returning the same evening!

i will go and see Daft Punk now,
see you tomorrow Smile

cheers,
gabi

Grumble · Posted: Sat Nov 03, 2018 4:09 pm Post subject:

increase the 6n8 cap.

gabbagabi · Posted: Mon Nov 05, 2018 7:56 am Post subject:

well, what i would question are the two low-passes in serie

in the simulation they even start to swing a bit

i would try to decrease ( down to bridge them ) the resistor values

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