Boss BD-2 Mods

Although I don’t own a BD-2 any longer, I could probably kick myself for letting it go after playing a modded one. Stock it’s a good sounding pedal but once you apply some mods to it, such as what Robert Keeley has done, it’s like an entirely new pedal altogether. Now I want one again. Below are some mods that you can do to your BD-2 provided by Mr. Keeley himself.

This is not all-inclusive in what can be done to the Blues Driver. It is meant to give an idea of where the tone can be improved or changed. All of the changes are subtle but when packaged together offer a nice improvement.

  • D3 - Change this 1SS133 to a different (1N4002) diode for asymmetrical clipping. This adds second order harmonics. This adds to the tube type sound. I like the sound of this change.
  • D7 D8 D9 and D10 - Change 2 of of these diodes from 1SS133 to a single 1N4002. More second order harmonic distortion. Although the change is slight, I like it. We actually take out one of the two pairs and replace it with a single 1N4001.
  • C1, C7, C6, C12, C13, and C15 - Change this electrolytic capacitor to a 10uF Non-polarized caps. Non-polarized caps sound better . I like these anywhere there is signal coupling at this high a value.
  • C14 - Increase input coupling capacitor value to 0.1uF for increased bass response from your guitar.
  • C100 - Here is where we can affect the tone control. I prefer a little more lower-midrange and bass frequencies through the tone section. You can increase the lower frequencies by increasing the capacitor value to 0.033uF. Install a switch to add a 0.068uF cap in parallel with this value for the Phat Mode!

Most of the ceramic caps are changed to Expensive Silver Mica (available through Small Bear Electronics www.smallbearelec.com or www.mouser.com or www.digikey.com). This is what makes our mod sound so good. A noticeable reduction in noise. An increase in the smoothness and no harshness left. This type of upgrade is not found in anyone’s mods. The best sound is right here.

Copyright by Robert Keeley
December 2002, Updates on August 2004