Guide to dating DOD FX-series pedals by serial number

Some early DOD FX-series pedals have stickers with the date of final assembly, but unlike Boss pedals, the month and year of manufacture is not encoded in its serial number. However, like vintage guitars and amps, the date of manufacture of most any effects pedal can be estimated by examining the date codes of its components. 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 160+ 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. The main limitation to such an approach is that the date of assembly of the complete pedal would necessarily lag the newest component date code, perhaps by 2-8 weeks. Because the exact lag time is unknown, we decided not to include a "fudge factor" in our plot below:

Several features of the plot are immediately apparent:

• The curve appears to start after serial number 100k (100000) in 1982, and indeed we have never seen any FX-series pedals with a serial number lower than 100k.
  
  
• At the beginning of 1983, serial numbers appear to abruptly step up to 200k. We have never seen a DOD FX-series pedal with a serial number between 117k and 200k.
  
  
• Between serial number 200k (1983) and 1600k (1996), the correlation is sequential but nonlinear as production increased or slowed down. Even with a couple of outliers, the correlation between serial number and component date is nearly perfect (r² = 0.995 for a 4th order polynomial curve fit). As DOD's FX100 pedal board (made in the 1980s) required one to remove the pedal's bottom plate for attachment, which could result in the wrong plate being re-installed after the pedal is removed from the board, such a high degree of correlation during this time is especially striking.
  
  
• One such outlier is a FX15 Swell Pedal at serial number 408k. As the FX15 was a slow seller, it is reasonable to assume that many circuit boards were initially assembled but not immediately housed in an enclosure, which would explain why the component date was about two years older than its serial number.
  
  
• Five related pedals (represented as red circles, including four DigiTech PDS-series twin pedals and one DOD Master Switch 225, each using the same type of serial number sticker) fit very well with the FX-series data. 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 curve is obviously no longer sequential. We have not yet opened up enough pedals from this time period to completely explain the bifurcation of the curve.
  
  
• By the end of the century, all DOD production had moved to China (VFX and GFX series, usually with a leading "V" in its serial number). Given the scope of this website, we have not examined the correlation between serial number and component date for Chinese-made DOD pedals.
  
  

Feel free to download this plot for your own private non-commercial use, to "date" your DOD pedals, but please do not post our work elsewhere on the internet. We reserve the right to update the plot at any time, so it would be better to just link to this web page.

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