Rene Schmitz 555 ADSR

ErichBreakfast · Joined: Nov 30, 2008 Posts: 20 Location: Massachusetts

I just built two of the Rene Schmitz 555 based ADSR's and I cannot seem to get either of them to work. The schematic on the site seems a bit open-ended. I noticed that the 2.2 uF capacitor is not shown as an electrolytic although it is in all of the other ADSR's similar to it. Also it does not specify what kind of NPN's to use. I built mine with BC547s but I'm not sure if this was a good choice or not. I'm still very new to electronics and synthesizer building. Has anyone had any experience building these and found anything funky about the schematic that should be noted or anything else that would help in getting this circuit to work? I'm pretty sure my wiring is correct according to the schematic in both circuits. I'm considering trying to build the design from the magazine on yusynth that's very similar to the Rene Schmitz circuit but without the transistor buffer circuit to see if I can at least get that to work. Any insight would be greatly appreciated. Thanks!

Erich

scriptstyle · Joined: Jan 22, 2008 Posts: 250 Location: nj

I have not built this or even looked at this schematic. But I know a common problem when using bc547 as a replacement is the pinout is differnt from similar trani. But it should be fine. Hope that helps.

slacker · Posted: Sun Mar 22, 2009 6:58 am Post subject:

Try having a look at the Yusynth version it's basically the same and he gives a really good explanation of how it works that might help with debugging yours.

synthmonger · Posted: Sun Mar 22, 2009 11:15 am Post subject:

I built one and bread boarded it to see how it worked. Any NPN will pretty much do. It's a great ADSR and you can get it to repeat by running the output back into the gate in.

What application are you using it for?

ErichBreakfast · Joined: Nov 30, 2008 Posts: 20 Location: Massachusetts

I've been trying to test it with my VCO, VCF and VCA to see if I can get any kind of signal coming out of it but it's just not doing anything.

ErichBreakfast · Joined: Nov 30, 2008 Posts: 20 Location: Massachusetts

I built two of these and was finally able to get one of them to work. It turns out my mounting hardware, although insulated was still managing to short the +15 to somewhere it should not have been. On the second one I'm getting +15 where I should have ground and now I'm tearing my hair out trying to figure that but at least now I'm hopeful and have a working circuit for a reference. Spring break needs to be a week longer I think. Thanks for all your help!

Erich