A Slightly Easier Boss Chorus - The CE-2

This build is based on another gem in the recent Boss releases from AionFX. The Azure project is a slightly modified clone of the Boss CE-2 chorus. The original pedal was released in 1979 with a bass version following in 1987 using the same basic circuit. Unlike the Dimension C with only four modes that toggle, the CE-2 is a more conventional pedal with potentiometers controlling Rate and Depth. The Bass version included a Mix function to blend clean signal back in, which is brought over in the Azure project (as it can build both versions). Setting the Mix knob to full makes the effect identical to the original guitar circuit. You can get an updated version of this pedal as a Waza Craft for about $220, and prices for originals go north from there. So again, this is a great candidate for a clone.

Once again, this pedal has a high parts count, though nothing like the Dimension C. The build is also a little tricky because the bucket-brigade delay chip (MN3207 or MN3007) has to be matched with the clock driver chip (MN3102 or MN3101 respectively). Because the two delay chips have positive / negative supply pins inverted relative to each other, you have to add jumpers to the board to set the correct polarity. Unfortunately I forgot to take a picture of the back of the board which shows the jumpers, but I added an image from the build instructions to show their placement below underneath IC2.

In addition to matching the BBD and clock driver, the Zener diode (Z1) has to be matched to the BBD as well. The initial revision of the instructions had the wrong part listed in the build documentation for the Zener diode, but the right part listed in the parts spreadsheet. This was updated in late January to reflect the correct part number - so make sure you're using the most recent version of the build documentation!

For this particular build I also managed to dig up original transistors for the project including three SC732 and two 2SC945. Because these are long out of production, and the board is so tight, AionFX simply set the board up with the E-B-C layout for the recommended substitute transistors (2N5088) rather than the four hole set-up often used to accommodate different layouts. I therefore had to do a bit of gymnastics with the transistors to ensure they were aligned correctly (and I ended up shrink wrapping the legs to prevent any contact. As you can see in the PCB photo at top, most of the transistors are slightly rotated - except for the one sort of trapped between two of the film capacitors.

As with most of my recent builds, I decided to go with a fairly standard enclosure on this one. It's just in the basic light blue used for the "real thing." I've seen some people adding a black field at the bottom of their boss enclosures to simulate the foot pedal. If I ever end up doing more of these, I may go that route as well.

Getting the bias adjusted correctly was fairly easy as it can be done by ear. There are instructions to set the bias with an oscilloscope, but that seemed like overkill since it is very easy to hear whether or not the pedal is distorting. The sound itself is great, but I'm not sure it is going to supplant my Dimension C on the board for the time being. Honestly what I'd really love to be able to build is a clone of the CE-1 Chorus because Alex Lifeson used one early on with Rush. Unfortunately there doesn't seem to be a clone available - largely because it appears some of the ICs for it are long out of production. Maybe with advances in home semiconductor fabrication (yeah, that is a thing!) some of the long out of production chips may come back to life.