The latest project I've been working on is a simple synthesizer, I don't know why I allways feel the need to keep my projects secret, perhaps it stems from being a mad scientist? Anyways I wanted to get some help, opinions and knowledge from you chaps regarding envelope generators and voltage controlled amplifiers. Primarily the envelope generators. Somewhere online I found this circuit (typically I can't find the website now) It looks so nice and simpl but it didn't work in simulation. Can anyone explain why? Is the circuit wrong or is my simulation software just not working? I spent hours faffing around with capacitors and resistors trying to make it work, but didn't get very far. In the end I came up with something based on a 555 timer monostable circuit which works in theory. At which point I was thinking "Why did I even consider using any other IC?" (circled numbers are pins of 555 timer chip) Taking the voltage from the capacitor (with a voltage follower) I should be able to get those shapes. Do you chaps think this will work too? Do you think my trigger input circuit will function correctly; making the monostable circuit trigger on the rising edge of the input pulse? Just thought, I could take the diode in series with R3 and connect it directly to +V allowing for very steep attack. Any envelope generator circuits you chaps can suggest would be much appreciated.