General Purpose End of Cycle Pulse Generator

DGTom

Hi All,

I was looking at this mod for my Blacet EG1;

http://www.buzzclick-music.com/Blacet_EG1.jpg

& the description here...

http://www.buzzclick-music.com/mods.html

(bout 2/3rds down the page)

... mentions this should work with other AR (and/or AD?) type EGs.

This got me thinking; as I use mostly simple envelopes in my 'music' it would be great to have a bunch of these on hand as a module or built into the EG1s, my pair of Metalbox Dual ADs & any others I build in the future.
So I put it together with a PN2222A, because thats what I could get locally - looking at datasheets I'm not sure this is 100% the same as the metalcan 2N2222 package Confused

The results I'm getting are not an End Of Cycle Pulse tho; the output is (about) 10V then as soon as the input EG is triggered it fires off its pulse (actually way faster than my DMM can register) - regardless of the actual incoming envelope shape.

I've triple checked everything is correct, should this work? is there a better way to do it? I know there is another way to get an EOCish pulse from the EG1 so I may just do that, but a general purpose cct. would be very usefull. Any thoughts or a push (slap) in the right direction would much apprciated Very Happy

frijitz

DGTom · Posted: Thu Oct 01, 2009 5:59 pm Post subject:

Thanks for taking a look Ian Very Happy

See, thats what I thought & as far as I can tell the differances between the 2N2222 & the PN2222 can't really be making that much of a differance.

The "non-inverted" thing thru me I think, because the Blacets have two front panel outs - normal & inverted. I'll have abit more of a play with it today but to be honest I can't see how the cct. is supposed to 'know' when the cycle is finished, with that comparator at the front it sure as heck knows when its started Laughing

I think this one will end up in the " would be nice if it worked... but Rolling Eyes

" file.

Thomas

fadeddata · Joined: Dec 27, 2004 Posts: 43 Location: Nashville TN

Hello Thomas,

I believe the Serge DUSG and CGS VCs do what you are looking for with an LM3900. Check out the "End Out" part of the CGS75 VCs circuit:
http://www.cgs.synth.net/modules/cgs75_vcs.html
http://www.cgs.synth.net/modules/pic/schem_cgs75_vcs.gif

I've had most of the circuit breadboarded up for the last 2 weeks and have been unable to get any kind of trigger from the End Out. It seems like such an incredibly useful circuit...

-dustin

DGTom · Posted: Thu Oct 01, 2009 6:29 pm Post subject:

That was actually the first place I looked when it occured to me this would be a nice standalone module, the End Out of my Frac VCS gets used in every patch & I plan on building some more.

After looking at the schem it seemed to me the EOC section was too integrated into the inner workings of the VCS to be amputatable. The VCS isn't the only device that features an EOC pulse so there must be other ways of doing it.

The EG On section (super sensitive comparator) works a treat tho & that's a cool little function that should be more comman on EGs IMO.

Edit;

Well... it seems I spoke too soon! By processing the Inverted output of the Blacet EG1 it does indeed work! Great Very Happy