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 almost 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 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. 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:
One caveat when using this plot is that when DOD rolled over from serial number 999999 to 1000000, the leading "1" was included in smaller text in the line above the rest of the serial number. Thus, be sure to include the leading "1" in your pedal's serial number when it is present.
Several features of the plot are immediately apparent:
- Production 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 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.
- Between serial number 200k (1983) and 1600k (1996), the correlation is sequential but nonlinear as production increased or slowed down. Even including a couple of outliers, the correlation between serial number and component date is remarkable (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 of the outliers 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 assembled but not immediately housed in an enclosure, which would explain why the component date was about two years younger 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 of which used 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 plot is obviously no longer sequential. However, the bifurcation of the scatter plot might be explained if pedals are sorted by series and then by the type of serial number sticker used.
- The x-axis of the plot was modified to include the year 2000, and the date code of three final-series pedals (a FX25B, FX84, and FX91) that had been previously assumed to have a date code of late 1999, were revised in April 2011. With respect to component date codes, the rollover of two-digit year codes from 1999 to 2000 was not clearly understood at first, but started to make more sense as we re-examined component-side circuitboard pictures of those pedals. For example, we now believe that a pot stamped "2009" is a date code meaning the 9th week of the year 2000. However, additional pedals will need to be opened up and examined to verify this hypothesis.
- By the end of 2000, 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 it 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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