Pork Barrel (CE-2) Chorus 12v w/ Mods

[satriale]

This is Mad Bean's CE-2 clone project running on12 volts via charge pump with a couple of mods. It was my 3rd build and I learned a lot with this one. I think these mods were originally part of the project but were left off in later builds. I found them on another project (Chorale) and compared schematics to get it right. Initially I wanted to do the speed shift, bass, and depth mods. I planned to put the depth mod (C21) on a foot switch but when I wired it up with the extra 100pf it was just way too deep — the range was maybe a semi-tone. So I ended up with just the speed shift and bass response switches.

After the initial wire up, some of the scrap 26 awg wire I used broke off so I decided to replace it with some new silicone 24 awg, which is pretty good (doesn't burn). As you might be able to see, I had some trouble removing the wire and burned the 9v for the led.

The first time I put it together I had the pots soldered directly to the board and everything sounded great. However, after wiring them so they would fit my layout I had some fairly loud ticking from the LFO that wouldn't go away regardless of how I positioned the wires. I ordered some MC1458P op-amps for the LFO to replace the TL062 and that didn't do anything to help. Their legs were also extremely brittle and both 1458 chips I bought now only have 7 legs. I ended up doing some more research about adding capacitors to the op amps. It turns out the 1uf electrolytic across pins 2 and 3 reduced the ticking a great deal. Moving the wires around a bit got rid of the rest, so there's 0 ticking now. Can anyone explain why the 1uf capacitor across the in- and in+ reduced the ticking so much?

The fat lettering is a result of smeared toner from the attempt at an acetone transfer. I had settled at 4:1 acetone to 90% isopropyl for pcbs and maybe I pushed on the text too hard. I have a brother printer so it's been pretty tough. I figured it sort of looks like the letters are underwater with the octopus so I just etched it. I use the copper sulfate method with root killer and salt for enclosures (doesn't work for copper pcbs).

By the way, it sounds amazing. I had been using an old digitech hardwire chorus and when I compared them I was blown away. I'm also a fan of alternative 80s music so this is basically the sound that I'm looking for. I'll probably build a Julia eventually but I'm really happy with how this turned out.

[satriale]

Gut shots

[jimilee]

That looks damn good. Nice etch.


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