The DOD Overdrive 250 DIY replica kit from General Guitar Gadgets is a build-it-yourself take on the DOD Overdrive 250, the DOD distortion pedal from the 1970s. The maker describes it as a great sounding distortion pedal reminiscent of some of the great sounds of the 1970s, and considers the 741 IC essential to that sound1. The kit covers two versions of the original: an early version in a gray painted box and the later yellow box version1.
What the kit includes
The kit comes with the Ready-to-Solder Circuit Board (RTS PCB) included, so the board does not need to be bought separately1. The bill of materials is version 2012January30, copyright 2009 JD Sleep, and the build instructions are version 2021October03, copyright 2014 and 2021 JD Sleep1.
Among the parts listed:
- J1 stereo quarter-inch jack and J2 mono quarter-inch jack for input and output1
- J3 DC jack for power1
- Sw1 heavy duty 3PDT foot switch1
- B1 9 volt battery (not included in the kit)1
- IC1 JRC741 op-amp1
- D1 and D2, 1N914 or other clipping devices1
All of the above from the maker's project page1.
Controls
The circuit has two controls, both set out in the bill of materials1:
| Control | Part | Potentiometer |
|---|---|---|
| Volume | R10 | 100k log (audio) taper |
| Gain | R7 | 500k reverse log taper |
For builders adapting the board to an MXR Distortion Plus style build, the volume potentiometer has been traced as 10k log or 50k log on some versions, the reissue has a 100k log potentiometer, and 100k log is recommended for best output volume1.
Gray versus yellow versions
The two versions the kit covers differ in a few part values. R6 is 4k7 in the standard build; the gray version had a 47k value, which should raise the minimum level of overdrive to some extent1. Two other parts vary across versions: R12, a 100 ohm resistor, was present on some versions and not others, and with strictly battery power it is probably not needed; C5, a 25pF capacitor, is present on some versions and absent on others, and with a 741 IC it is probably not needed1.
If you build the gray version, the 47k value for R6 raises the minimum level of overdrive compared with the standard 4k7 build, so the pedal will break up sooner at low gain settings1.
The circuit and its relatives
The DOD Overdrive 250 is very similar to the MXR Distortion Plus pedal, and General Guitar Gadgets uses the same circuit board for the MXR Distortion Plus, the DOD 250 Overdrive, the '77 gray DOD 250 Overdrive and the Ross Distortion, describing these units as very similar, differing in only a few part values, the circuits being almost identical1. Griffin Effects sells a board along the same lines, writing that it is based on the DOD 250 Overdrive and that you can also build the DOD YJM 308 and the MXR Distortion + with it2.
The op-amp is central to the design. The kit specifies a JRC741, with the UA741 and LM741 fitting the same 741 type1. The current DOD 250 reissue keeps the same part: Delicious Audio's Paolo De Gregorio writes that the new 250 sports the LM741 OpAmp just like the original, and that the updated version uses the vintage correct LM741 OpAmp, just like back in the '70s3. MusicRadar's review of the 50th Anniversary 250 notes optional battery power and 1/4-inch input and output jacks with a 9V DC power supply input4.
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Questions
Does the DOD Overdrive 250 DIY kit include a battery?
No. The bill of materials lists a 9 volt battery as a separate part, marked as not included in the kit. If you plan to run the pedal strictly on battery power, General Guitar Gadgets notes that the optional R12 100 ohm resistor is probably not needed, since it relates to power filtering on versions that used an external supply.
Which op-amp does the Overdrive 250 kit use?
The kit calls for a 741-type op-amp IC, listed as a JRC741, with the UA741 and LM741 also fitting the same socket. General Guitar Gadgets considers the 741 IC essential to the sound, and the current DOD 250 reissue likewise uses the LM741, described as vintage correct.
Does the kit include the circuit board?
Yes. If you buy the kit, the Ready-to-Solder Circuit Board (RTS PCB) is included, so it does not need to be purchased separately. Builders who prefer to source their own board can buy the RTS PCB on its own instead.
What is the difference between the gray and yellow DOD 250 versions?
The kit covers two versions of the original pedal: an early version in a gray painted box and the later yellow box version. The main circuit difference is R6, which is 4k7 in the standard build but was 47k in the gray version, a change that raises the minimum level of overdrive. Some versions also vary on the optional R12 resistor and the C5 25pF capacitor.
Which clipping diodes does the Overdrive 250 kit use?
The clipping stage uses two diodes at positions D1 and D2, specified as 1N914 or another clipping device of the builder's choosing. Swapping the diode type is one of the common ways builders tailor a 250-style circuit.
Is the DOD 250 the same circuit as the MXR Distortion Plus?
Not identical, but very close. General Guitar Gadgets describes the DOD Overdrive 250 as very similar to the MXR Distortion Plus, and notes that the same circuit board serves the MXR Distortion Plus, the DOD 250 Overdrive, the '77 gray DOD 250 and the Ross Distortion, with circuits that are almost identical and differ in only a few part values.
Sources (4)
- DOD™ 250™ Overdrive Clone: DIY Kit, PCB & Schematic, General Guitar Gadgets, 2014-05-12
- YJM250 Plus PCB, Griffin Effects
- DOD 250 Overdrive Preamp, Delicious Audio, 2025-02-21
- “Surely the most versatile version yet, putting different flavours of gourmet crunch on the menu”: DOD 250 Overdrive/Preamp 50th Anniversary review, MusicRadar, 2025-02-04
