Zombie Chorus - some questions to begin with

[egasimus]

The Small Clone was my first DIY FX project some years ago. It passed clean signal, and I didn't really know what to do or where to ask for help, so I eventually abandoned it. I recently came across the Zombie Chorus, and I must say it sounds awesome. However, I've read about its ticking problems, and its pickiness about opamps (not that a TL062 is hard to procure for me), so I must ask - what is the most recent version of the Zombie? I'm interested in making my own layout, and will readily share it with the community.

[deadastronaut]

hi adam, i built he zombie a long time ago, i did the ticking mod and it was a great chorus...no ticking at all, and very lush...

i havent got the pedal anymore, but i would definately build another...but with a blend pot on it too ...i had to stick a trimmer on the output to get bypass unity...

i can't find the tick fix link at the mo...sorry, but a new layout would be cool....1590b would be great!...

http://www.youtube.com/user/100roberthenry?feature=mhum#p/u/30/HxvZKri-5QA

[egasimus]

I've seen the de-tick mod, and could probably recreate it from memory - just separate voltage dividers for the audio path and for the LFO as far as I remember... However, some thread of some guy asking for help about it had a reply along the lines of "how do we even know which version you're building?", so that made me think there were at least several ones. Sticking to the one from J. Hollis' site (+tick mod) would probably be safe, but I'm trying to build the best that can be... so if there's another mod or redesign, I'd like to add it to my layout.

P.S. I'm using either 125B or ??x8x4 boxes (made from aluminum profile, open from the side), but I'll definitely try to fit it into a 1590A. Although I don't have such an enclosure, and have some concerns about height - I guess it's finally time for me to try out Eagle3D...

[lopsided]

I have build Zombie Chorus on perf without the deticking mod, and it works fine. It doesn't tick just sometimes does kind of silent swooshy sounds in the background .
There is a perf layout in the galleries http://www.aronnelson.com/gallery/main.php/v/Xaviers-shrine-of-noise/Layouts/Zombie_001.gif.html?g2_imageViewsIndex=1
which I used, but it has a couple of mistakes as much as I remember.

Besides the Hollis schematic there is a slightly updated verison at geofex with a PCB layout http://www.geofex.com/PCB_layouts/Layouts/zombie.pdf
The deticking mod is elaborated at mark hammer's site http://hammer.ampage.org/?cmd=lt&xid=&fid=&ex=&pg=4

[egasimus]

Hello again. I still have no progress, but it's for a good reason - I remembered that the original Small Clone had a stereo mod, and decided I'd like to add that, too. What does it even do, though? And can it be incorporated into the Zombie, too?

[Mark Hammer]

Attempts at de-tickification will be far more successful if the  builder does NOT use a quad op-amp.  It is the LFO portion that produces the tick.  De-ticking mods provide for separated power lines for the LFO portion and audio path.  If the 2 op-amps for the audio and 2 op-amps for the LFO are rolled into the same quad op-amp, you can't do the separate lines thing.  So, as much as I appreciate the effort he put in, and the seeming convenience of it, you should probably avoid Tomboy's layout for the Zombie (at least the 2004 version I have in my files), since it uses a TL074 quad op-amp that precludes separate filtering of the LFO power line.

[egasimus]

That's something I would've overlooked. Makes perfect sense though, and I'll definitely take it into consideration when designing my layout

[Mark Hammer]

It's something a lot of folks would have overlooked because one's attention is usually quickly drawn to things like cost, footprint, etc.  It took me years to learn to pay attention to stuff like this.

[egasimus]

I decided that there's no point in adding the stereo mod. I finally found Moosapotamus' site and heard some samples of it, and wasn't really impressed. How about a mix pot? Would just putting a 20k pot instead of the two 10k mixing resistors at the output work?