Thanks for your help, I did all that, I always power my modules without ICs to check the various voltage supply points.
I have inspected all traces with a loupe and scraped the gaps with a blade to ensure there are no shorts.
I am really looking for input about the circuit, a schematic, or an explanation of which part could cause the output to remain constantly up.
Stripboard often fools me and i can take an age to find which hole I’ve missed. Post a side by side photo so we can all have a go at spot the difference. The thread @analogoutput posted is a great fault tracking start.
Can you post a link to the diagram you’re using?
Disconnecting everything from the center pin of the mode switch.
Disconnecting the LED.
I’ve been over the board several times, hopefuly someone will have sharped eyes.
I will reprint the layout in the morning and draw over all the traces again, but I am pretty sure I built it right, I did both at the same time…
Hello everyone! I hope you are all doing great ! I am posting here because I am facing an issue with the simple envelope circuit, designed by LMNC.
I’m a beginner so I focused on the basic envelope design (no push button just Attack, Release, Gate, CV out). I finished the build but for some reason the envelope cv out goes negative whenever I dial the release parameter almost all the way down.
Do you think this is normal? When I plug my Neutron’s ADSR into the oscilloscope, it never returns negative values.
Do you think you could have a look please?
I add pictures of my build so that you can have more information on this issue.
I thank you all in advance for your help or comments have a great day.
(also this is my first post so you can let me know if this needs to be moved somewhere else, I did not want to start another thread)
I don’t see how that can happen if it’s built right. There’s a diode between the buffer op amp and the output (and resistor to LED). If the capacitor voltage is negative then current cannot flow backwards through the diode, so there can be no voltage drop across the load to ground, so the output must be zero volts.
Furthermore the capacitor shouldn’t be charging quickly up to a negative value. The incoming trigger should charge it quickly to a positive value, and then it’ll decay to about -10 V, but it shouldn’t charge quickly up to that.
So I’d say something’s wrong with your build. See:
Since you have a scope, check directly:
Voltage on the capacitor, should shoot up to (about) +10 V and then decay to -10 V
Voltage on the op amp pin 1, should alternate between (about) +10 V and -10 V
Hi and thank you very much for the detailed reply!
Yes the module is powered on, on the picture (I had this other cable sticking out of the case which made everything confusing sorry). I checked the circuit many times and found nothing wrong.
I recalibrated the oscilloscope just to make sure but this negative voltage still occurs when the release is at 0. As visible in the pictures below, when the release is not at 0, the signal goes to the negative territory as well but at -0.48V only, this issue is more dramatic when Rel = 0.