Ideology Behind the Mod:
After playing with Boss BD-2 for a while I was not impressed. No blues player would ever need the gain this unit puts out. Even the minimum gain was blowing my head off. This pedal was very shrill sounding, I couldn’t use the tone control at all, way too piercing. There was also fuzziness and buzz when the gain control went past noon.
Anyways I like bright clear tones and fat tones and I am not a huge fan of over the top gain. With this is mind I started moddifying the pedal’s circuit.
Before you Modify your Pedal:
Before you go slap happy tearing out components and “modding” away. Though this is not an intensive mod it still involves quite a bit of work. To make sure your pedal sounds great and works at the end I recommend testing the pedal after you finish desoldering and soldering in four or so new components. That way if your pedal doesn’t work it’s easier to find the problem. I did this but with every component. I did this when I was developing the mod and wanted to hear things rather than make sure they worked.
A hint for removing Boss’ industrial lead free (RoHs) solder. First heat up the joint so the solder melts, then heat again and apply a bit of your own lead solder (i.e. 60/40). After this is done you can go about removing the solder with your desoldering braid or pump.
R21: 2.7K (could wire a 5KΩ pot here for a contour control)
C17, C19: 0.01µF
C19: I didn’t touch this cap but for a mid boost remove this cap. More mids, more gain.
C101: Wire a DPDT (On-On) switch on C101 to select between a 0.033µF and a 0.068µF cap. This switch allows you to go from a normal tone to a fat thick tone.
D7, D8, D9, D10: 3mm Water Clear High Brightness Red LEDs. These are clipping diodes. LEDs make the pedal fatter, tighter and more compressed. I also find they add some dynamics to the pedal. They also clip much less than a standard diode so you get more headroom!
The next part of the mod is what I would call a Hi-Fi mod. No values of parts are changes. Instead the material of certain capacitors (di-electric) is changed to a nicer better sounding material. Don’t cheap out here and not do this part of the mod. Without this part I seriously doubt the pedal would sound so good. It may not be the most interesting part of the modifications but it’s worth it.
Use all Silver Mica caps here.
C21, C23: 47pF
C20, C25: 470pF
Use tantalum capacitors here
C1, C6, C7, C12, C13, C15: 10mF (16V or higher)
This part of the mod is great. All the fuzz and fizzeyness when the gain control was turned up was gone. Clarity was increased and the pedal had more dynamics and felt like it responded better to my playing.
D10: 5mm Water Clear High Brightness Blue LED (this is a new indicator LED)
After performing the above mods the pedal sounds much better. It is nice and clear and warm or with a flick of a switch it is fat and compressed both ways retaining excellent clarity though. The tone control is totally useful now and much more versatile. The gain control is quite useable and one can actually have a low gain sound now.
You can set the gain so low the pedal can be used as a straight up clean boost. It can still do some great crunch/post crunch tones but no more metal. It responds to my touch and feel. I tested this pedal with nine different tube amps, one solid state and three guitars and it sounded great with all of them, mission accomplished.
A cheap pedal turned into a cheap very useable pedal!