Sadly, I can’t. Even if I hold the push button for eternity, nothing happens.
I double-triple checked the board, and everything seems in place. Nevertheless, I’ll check it again, maybe I’m missing something obvious.
Sorry if i 'm not clear, you can’t use the Attack pot with a Trigger signal, it’s normal with this module. A trigger signal is too short for that .
You can only use this attack pot with the switch on Gate position,and with a Gate signal in.
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Ah, that’s sad. Thanks for your help!
This cannot be overcome with some simple modifications, can it?
I don’t now, maybe look here
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I tried this but now AD mode works just like AR.
EDIT: this was because I messed up soldering. Correctes the mistake, AD does not act as AR - - but the original issue is back, AD only works with minimum attack.
That’s what it says on Bergman’s stripboard layout: “Triggering only works with short attack times”.
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Yes, you all must be right. It’s just a bit confusing for me, I thought maybe I messed something up. Anyways, AR works great and AD can be used for cool percussive sounds with this short attacks!
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Hi, I made a simple AR env-gen and it seems to not work somehow. I altered the stripboard layout slightly to fit it on a smaller bit of stripboard, but I’m confident what I’ve done should be fine. I believe my problem is coming from the TL072, but I’m not 100% sure. It’s getting +/-12V fine, but the voltage readings on some pins are peculiar… If anyone could let me know what sort of voltages should come from the op-amp that’d really help.
My readings of the TL072’s pins are as follows
1: -10.75V
2: 2.09V
3: 0V
4: -12.05V
5: -5.39V
6: -10.69V
7: -10.69V
8: 11.97V
Sorry i don’t know for the pin Volt
but here’s a thread maybe can help you to check your build
what the problem ? with what are your testing it (to send a trigger/gate signal) ?
have you some pics ?
(btw maybe you can deleted your other thread about that 
)
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The pin voltages aren’t all that useful for most pins because the inputs and outputs should be varying. Pin 2 is the comparator threshold and should be constant at 12 V x (10k/(10k+47k)) = 2.1 V. Pins 4 and 8 are power and should be -12 V and +12 V respectively. The rest should depend on the input gate and where you are in the envelope evolution.
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Is there a reason this circuit needs a bipolar supply? Aren’t envelopes positive-going only?
If i look at the synthnerd envelope, which i have myself and works, it only has the positive supply.
It seems to me that if the comparator has a bipolar supply, the output will swing to the negative rail when there is no signal at the gate/trigger input. This will then bring all the pins of the second opamp, a voltage follower, to negative 12 volts and also charge the timing capacitor to -12 volts.
It’s been a while since i had opamp theory in school and circuits like these are not my strongest subject, but it seems to me something isn’t right in those conditions.
Will the timing capacitor ever go positive? The diode at the output will prevent any negative voltage from coming out, but i’m thinking you might get a ‘negative going’ envelope at pin 7?
Maybe someone can elaborate 
I might be completely wrong though…
https://www.bristolwatch.com/ele2/comparator.htm
This article confirms that the output of the comparator will go negative. I’m guessing either that at gate/trigger input, the comparator will bring the capacitor from -12 to something less negative or 0 volts, or that the envelope might be inverted or something and not coming out because of the diode at the output
Edit: have you tried connecting pin 4 to ground instead of -12?
The TL072 isn’t a rail to rail opamp. If you power it with +12 V only, the output won’t get anywhere near ground.
Here’s my stripboard layout, excuse the mess of breaks on there, that’s just how I mark out my stripboard size.
I’m using gate signals via a midimuso CV-12, not triggers.
As I say, I think power is fine, and pin 2 is pretty much 2.1V so that’s fine, it’s just the rest of the pins I’m confused about. I’ll test what I sort of voltages I get when sending in my gate signal.
Ok, pins 6 and 7 are getting a consistent -10.69V. Pin 1 is jumping between -10V and +11V (excluding the decimals) in a rhythm consistent to my gate turning on and off. Pin 3 is going between 0 and 2.17V, which I think is a good sign that the signal is getting to the non-inverting input. Pin 5 is going between around -10V and -2V depending on where the release knob is set, no release being approximately -10V to -3V, full release being around -5V to -2V. It is moving slowly rather than jumping line pin 1, but not in a way consistent with release time.
The attack knob doesn’t seem to do anything.
By pure chance I’ve just noticed that if I connect pin 5 to ground the gate works, but the attack does nothing and the release acts like sustain?? Even on a simple circuit like this I feel way out of my depth
Pins 1–3 are a comparator; when pin 3 (gate input) is below 2.1 V pin 1 should output ~ -10.8V and when it’s above 2.1 V pin 1 should be ~ +10.8V. It seems your gate is only going up to 2.17 V which is enough to change the comparator but only barely. The two 100k resistors form a voltage divider that cuts the gate amplitude in half, so you need at least 4.2 V for your gate amplitude at the input. (Oh, wait, I guess there’s a diode drop to figure in too.)
Pins 5–7 are an output buffer. Pin 5 connects to the capacitor whose voltage is what makes the output as it is charged up (attack) and discharged (release). It should vary with time so any particular value isn’t very useful. Pin 7 is the buffer output and it’s fed back to pin 6, so both should read the same voltage, but again it will vary.
Yes. When it’s +11 V it charges the capacitor through one diode and the attack pot, when it’s -11 V it discharges it through another diode and release pot. So pin 7 should swing between ±11 V, and then there’s an output diode that makes it 0 V to ~10 V. Rather a crude approach giving a delayed and truncated envelope, but it does say “simple”. And indeed one could use a rail to rail op amp like an MCP6002 and then eliminate the output diode, with better results.
@CTorp’s K25 envelope generator, schematic here, is like that but uses an LM358 (which isn’t rail to rail but does go down to 5 mV).
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So I dont know where I saw this, but thsre was a link on this forum to a guy testimg all these out and he mentioned swapping a bunch of 100k resistors for 10ks, and then the 1uf capacitor for a 5uf one? Ive been trying to find a 5uf capacitor but all i can find are fridge parts and that wont do! Anyone know some keywords I dont so i can get the right part?
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“On top of the 1µF cap I put an extra 2,2µF bi-polar cap to get 3,2µF in total. (put in 5µF if you can)”
5 µF is a non standard value, but 4.7 µF should be easy to find.
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