The original transparent overdrive, this pedal has a mountain of clones, reissues and derivatives. Due to the low parts count and flexibility of the circuit it is a great starter pedal for beginners and a great way for more experienced builders to get into modifications.
A great article on this circuit can be found at premierguitar.com that was written by Brian Wampler about some of his go to mods for it.
- Output – Controls the overall output volume, this is actually quite low and unity isn’t until about 3 o’clock on the dial. Common modification is to increase the potentiometer from A10k to A100k
- Distortion – Controls the amount of clipping in the circuit. As you turn this dial up the bass will start to roll off making the highs more pronounced.
- Designed for a 125B enclosure with top-mounted jacks
Zach Omega (verified owner) –
I built this as a DOD Overdrive 250 so many of the values don’t match the board. I used a C taper put on the gain control as well instead of linear.
I used a jumper instead of the series diode to keep the voltage up. I also placed a current limiting resistor for the led on the board where the led goes and wired the switch output from the board to the anode of the led and the cathode of the led to the switch input on the foot switch board.
It sounds fantastic! Kind of the original transparent overdrive.
I’d have given it a perfect score if it had the current limiting resistor on the board. And really that is only a minor inconvenience. It really deserves 4.75/5 stars as it is now.
I’ve now built 2 of these at this point, one a Distortion + with N134A germaniums and another as a DOD 250 ’77 Grey with C3 modded to 220nF, C4 at 10uF and A500K and A100K for pots. Both are awesome but the DOD version really screams. This is an easy build and a nice fit in a 125B so you can really clean up on the wiring.
Bixbillion (verified owner) –
Built 2 of these: one to the original layout which I believe is closer to a plus and another based on grey spec 250 mods found the forum. Both sound excellent and are really simple satisfying builds! The 250 has become my new main overdrive and the distortion plus sounds suprisingly good on bass.
LeftyPicker (verified owner) –
For some reason I had the idea that hard clipping was the way things were done before we figured out to really do it with soft clipping, so I built this out of curiosity and respect having read some DoD 250 history. Well I learned that hard clipping is in some ways more authentic because it actually loads the output of the miniaturized push-pull amp in the classic 741. Saturates quickly into thick distortion with Ge diodes, so you’ll use most of the available volume knob, and there isn’t a lot of boost available. I like the gain pot in the base leg of the feedback network that with the cap tightens the bass as you add drive. More dirt than I drive daily, but glad I built it.