Hi everyone!
I have just built the LMNC simple envelope generator with ad/ar switch but I can’t get it to work quite right…
The button doesn’t work but when i flip the switch it can do a sweep (when plugged in to an oscillator)
The trigger in doesn’t work either (when tested with a beatstep pro…)
I filmed this to help explain the problem: https://youtube.com/shorts/JSmioRiSSi0?si=wkEt1UGMsa5W-kT2
Here are some pics of the module and stripboard:
Am I missing something totally obvious or is this something a bit more complex? I am a bit new to building modules so if anyone would be able to help I would be very thankful!
All the best!
//Vincent
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I can’t tell at all what’s happening in the video, I think you need to explain it in words in more detail.
I will do my best to explain the problem, sorry for the bad video!
So the button doesn’t work at all, no matter what position the switch is in, when the switch is in down (gate mode) nothing happens, but when I flip the switch up (trigger mode) it works as if you would push the button in Sams version, I can adjust the envelope time and use the switch to trigger envelopes, (witch the button is for, if I am understanding everything right) this is what I tried showing in the video…
Hope this helps explaining the problem a bit better…
Well, that’s weird.
Here’s a schematic
I assume by “gate mode” you mean what is labeled “AR” here and “trigger mode” equates to “AD”.
The button should be almost foolproof. Your multimeter should show it has +12 V on one terminal and on the other terminal it’s 0 V when not pressed, +12 V when pressed, and the latter terminal should connect to the middle terminal of the switch so you should see the same there. When the switch is set to AR (gate mode) you should see the same at the upstream end of R4 and about the same at TL072 pin 3, except the “on” voltage will be lower, around 6 V. With AD (trigger mode) you’d maybe see a short blip on R4 and pin 3 but back to zero right away.
If that’s all right then I offhand can’t think of any way the switch could trigger an envelope but the button can’t.
The one thing I can think of is: Is there any chance your pushbutton is normally closed? (+12 V on the output when not pushed, 0 V when pushed.) I can sort of imagine how that might produce some of the behavior you’re seeing.
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It appears that the problem was me being stupid and not checking the button, it is a normally closed button!
(Slams hand against face)
I soldered on a normally open button I had laying around and now everything works fine!
Thanks so much for the help!
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Did exactly the same thing with an envelope generator build once.
One of these buttons is not like the other two…
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It’s that kind of thing you do once (hopefully 
) and remember every time you go and order something…
