building my adsr generator in real life

Discussion in 'Analog & Mixed-Signal Design' started by Green Bean, Jul 10, 2018.

  1. Green Bean

    Thread Starter Member

    Mar 31, 2017
    123
    1
    I built a very simple envelope generator with just diodes and a transistor, and got it working too, but it only had attack and release settings and I was not satisfied with it. So I spent some time looking around at schematics online and found quite a few but I just didn't have the right parts to build them and I'd like to use what I have and not have to order anything. So I tried to design my own. Here is the original schematic/sim: http://tinyurl.com/ya642f3b

    adsr generator_ya642f3b_Green Bean.png

    The top pot controls the attack time, the middle pot controls the decay and release time, and the bottom pot controls the sustain level. The little "L" is the gate signal (click on it). I designed this with the idea that I could use a 555 timer as a combination schmitt trigger and flip flop. Well, it turns out it's a bit more complicated than that and I had to scrap that idea. However, I was able to figure out some things. Here's the practical design so far: http://tinyurl.com/y926pj7f

    adsr generator_y926pj7f_Green Bean.png

    Now I have some questions:
    1. The inverter going to the trigger on the 555 I is acting like a inverting schmitt trigger in the sim. I do not have any inverting schmitt triggers, only normal TTL inverters. The point of the inverter is to activate the 555 timer once the attack cycle is complete. A cap slowly charges and eventually the voltage is enough to flip the inverter. My question is, do I really need the inverting schmitt triggers for this or can i just use my normal inverters?

    2. The other problem is the opamp (acting as a voltage follower). I don't actually have any opamps. But, I do have transistors and I'm thinking I could just make a simple voltage buffer with one and maybe some resistors. Given that I would be using 3904s and running on 5V, how would I do that?
     
  2. Green Bean

    Thread Starter Member

    Mar 31, 2017
    123
    1
    UPDATE: I figured out the transistor voltage buffer. Here is the new schem/sim: http://tinyurl.com/yaybfo6g

    adsr generator_yaybfo6g_Green Bean.png

    With that out of the way I can actually try to breadboard the circuit and see for myself whether or not the regular inverters will be sufficient. I will report back with the results.
     
  3. ScottWang

    Moderator

    Aug 23, 2012
    6,359
    984
    Mods Note:
    Please upload a *.png file with the simulation links otherwise it may lose the links someday and this thread will be become useless.

    I already uploaded three *.png files followed the simulation link.
     
    Green Bean likes this.
  4. Green Bean

    Thread Starter Member

    Mar 31, 2017
    123
    1
    Ok thanks.
     
Loading...