DOD 250 Overdrive Preamp

DOD began in 1973. Or 1974. Or 1975. The history isn't clear.

What year did the 250 arrive?

Hmm...

In Art Thompson's "Stompbox," founder John Johnson says the began building guitar effects in 1975, with the "650 Phase Shifter" (the 650 model number is for a mini amp; this model number was either quickly deleted or Johnson's memory failed him for the interview) being the first effect. Later in the interview he says they were "already making our 601 Phasor [in 1975]." Again, no 601 Phasor can be found, but they did have 201 and 401 Phasors, so he must have simply forgotten the numbers. The 250 is only mentioned as being the top selling alongside the "650 Phasor."

The above schematic is undated, but it mentions the TL081, which to my knowledge did not appear until circa 1978, so this schematic is presumably no older than 1978.

This is an early high gain, op amp based amplifier with passive diode clipping.

Seems to be regarded as a copy of the MXR Distortion + (release date also vague). No one seems to care too much about this poor fellow, except for fans of shredder YM.

The earliest version of this pedal seems to be a fairly large version simply bearing the words "OVERDRIVE PREAMP" with no model number. Pictures of it can be seen here: http://www.effectsdatabase.com/model/dod/first/overdrivepreamp

I first notice this version in Art Thompson's "Stompbox" book.

The date codes can't be clearly read in the database.com photos, but the op amp is a 741 and appears to say '76.