Caesar Chorus

Locrian99

Well-known member
Build Rating
5.00 star(s)
Hello all, built this one a bit ago and thought I’d share my experience with it.

I was very excited to build this pedal, was top of my list since I started in this hobby back in. Chorus has always been a staple for me one of my first amps was was fender ultra chorus (yes ultra, think just the first year they were ultra then changed to ultimate.) Then I picked up a dod fx65 ice box, which i used for the last 20+ years. Built the Caesar and the ice box found Craigslist. Anyways.

So before I ordered the board I had to find some mn3207 and 3102. At this time I hadn’t found any from “reputable” sources. Seems like they’ve come available since. So I found a Chinese eBay seller and ordered three sets for I think 8$ after shipping. 3 weeks later my chips arrived. This was easily the largest project I’d taken on since starting building pedals so I knew I needed to test these so I wouldn’t be guessing when it came to trouble shooting. I found a circuit over on diystompboxes for a slapback type delay that used these chips so I put it together on a breadboard (also by far the biggest thing I’d breadboarded up until then) 91562983-750A-4DA3-B52F-4AAA4049AA97.jpeg 81B91E69-39E7-4DBF-94DD-B8F1E0821D09.jpeg

So here we go time to test this out. Plug it all in and I let out the magic smoke. The 3207 got very hot very quick. I inspect everything, if I remember correctly the problem was I attach pin 8 of the chip straight to ground accidentally. Fixed this, crossed my fingers and tried again with the same chips (maybe?). Nothing. Tried another set and it worked! But I had a terrible high pitch whine, had a cap by the 5088 coming back to mix in with the dry signal not right. Fixed that and were ready to roll. 3rd set was good as well. So I package all 3 back up label the bad ones bad and store them (more on this later.). Order my pcb.

Pcb shows up and start in on it. I was pretty nervous with just the sheer number of parts. But it really wasn’t any different than any other build. Just more of them. I didn’t know about the mlcc instead of led mod so I just did the red led’s plan on going back to change this. Also I was just wanting to make sure I got it right so I just wired the rate led normally (typically for rate leds I like to connect them to pin 8 of the 3pdt so they aren’t always on). Got it all put together and no effect. Wtf. I get my multimeter out start checking voltages. Stuff looks good then I get to the mn3207 and they looked way off to me comparing to the schematic. Started to wonder if my test circuit didn’t push the chips as far maybe? Didn’t know, but I knew I tested it and it was good. I decided to try another set of chips anyways. And voltages look better, plug in and we have signal. Bias it with the trimmer and we’re good to go. Decide to test the one labeled bad and it worked. So apparently I got my bad one confused… so glad I tested…


Anyways I love the pedal it is exactly what I was looking for and really while it looked intimidating was very straight forward and easy. 97C65E04-DC71-4429-9E90-C4AE3C98DC7F.jpeg B3A2801B-6ECA-4361-A6DC-DA2178A57098.jpeg 4C74067A-0690-4180-B22E-699FECA7C803.jpeg

Now this being such a cool pedal I wanted to do it up a little for the enclosure. I was thinking a nautical theme. And I always love the looks of old maps. Start searching around online and found what I wanted. Got it all done put the circuit in, flip it over to tighten down the pots and I put the blend label on the wrong side! Ugh, it’s just for me so I decided to leave it as a reminder to check. One of these days I will pull the red leds out and try the caps and order a 5mm red/green led so I can get the same rate look as that old fender chorus amp I had as a teen. B1E26949-8C25-46DC-9E55-A49525960FCD.jpeg

It’s got a permanent home now on my board. Very happy with it
 
That "looking at the pedal from behind" will get you every time hahaha, honestly bo big, pedal looks AWESOME and this is not an easy build by any means, great accomplishment!!
 
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