Almost all IC chips have date codes, and other components such as potentiometers, transistors, and electrolytic capacitors can also have date codes.After opening up 175 different DOD pedals and examining the components of their circuit boards for date codes, we plotted serial number as a function of the latest component date code found in each pedal.Although we only have data from four PDS-series pedals, it may be reasonable to use this plot to estimate the production date of all PDS-series pedals.In 1996, coinciding with the release of the re-designed final series of DOD pedals (FX64 Ice Box, etc.), the plot is obviously no longer sequential.We reserve the right to update the plot at any time, so it would be better to just link to this web page. There are 3 different versions as far as I know: Made in Japan - black label (1979 - 1984? Is this something that needs to be done at some point of time?Thus, be sure to include the leading "1" in your pedal's serial number when it is present.At the beginning of 1983, serial numbers appear to abruptly step up to 200k.
Feel free to download this plot for your own private non-commercial use, to "date" your DOD pedals, but please do not post it elsewhere on the internet.Whether it actually sounds better is debatable and down to opinion IMO.From Analogman's site: "The early Boss CE-2 used the 3007 chip, later Japanese and most Taiwan made CE-2 pedals used the 3207.We had never seen a DOD FX-series pedal with a serial number between 117k and 200k, until Jeff Kehoe sent us photos of his FX25 (SN 118400).It is possible that others may exist, probably closer to 118k than 200k. ) I wonder if there are any noticeable differences in sound between these models? I've seen some Ebay auctions where it says that the pedal has been recapped.