This is a custom pedal that I built that was based on the DOD 250 Preamp Overdrive. This is a great pedal to build for someone looking for a DIY project. The circuit is very basic and has a 741 op-amp at its core. The original grey 250s (pictured left) go for a pretty penny on eBay, and the newer reissues (also pictured left) are also climbing in value. The pedal even garners a special fan, Yngwie J. Malmsteen, and his fandom of the small grey box has earned him a signature YJM 308 Overdrive – again based off of the 250 circuit. In my opinion, it is a very under-rated overdrive pedal and had the potential, with some cubisteffects mods, to really become a versatile low/mid gain drive pedal.
This custom 250 has two footswitches – one for bypass and one to activate a clean boost. The boost can be used independently of the 250 circuit, thus providing three levels of gain (boost, custom 250 and custom 250+boost). The white knob controls the output volume of the boost.
The four black knobs control the Volume and Gain (as per the original design) plus a few modifications. There is an “Edge” control that limits the amount of signal hitting the clipping diodes. This provides a smoother tone and effects the character of the gain in a different way than rolling of the Gain knob. The fourth knob is a Tone control that rolls off high or low frequencies, and can be bypassed by the small toggle beside it. Bypassing the tone stack increases the output volume significantly and can really drive your preamp! The large toggle is a three-way switch that selects between three diode selections providing three different tones – fuzzy, boost and smooth. All of this in a hand-painted custom black and white swirl paint job as well.