This is the first Boss “compact” chorus pedal, because its predecessor (the CE-1) used a much larger gray box. Settings are straightforward: “Rate” for speed and “Depth” for effect level.
Sound is somewhat a classic, and lots of people prefers this to later models from the same manifacturer like the CE-3, CH-1 or CH-5, and even to any other chorus around.
There are different versions of the circuit, all of them using the MN3007 BBD chip. Moreover, there are both Japan-made and Taiwan-made effects: while some people says that the Japanese one sounds better, I must say that I’ve tried them both and couldn’t find any relevant difference in listening.
The unit has been sold from 1979 to the eighties: in the photo, you can see my slightly used old japanese one 
Specifications:
- S/N Ratio: 90dB or better
- Input Impedance: 470 kOhm
- Recommended Load Impedance: 10 kOhm or higher
- Current Draw: 9 mA
Resources:
CE-2 Schematic (and lots more) on Schematic Heaven website
CE-2 Schematic on Free Info Society site
CE-2 On Michele Cricco’s Blog with photos and samples (in Italian language)
CE-2 : a couple of great photos on Mode Zero site
Want to build a CE-2 style chorus? Check Tonepad site
Artists using the CE-2 on Guitar Geek site
An interesting comparison between the Japanese and Taiwanese versions