2nd Generation Boss Overdrive - Cloning the OD-2r Turbo Overdrive!

It's been over a week since I posted my last Boss clone, and sadly I'm still debugging one of the Boss PCBs I've been working on to no resolution yet. I'll keep banging away at it though. In the meantime I've finished up another one of the recent releases from AionFX, the Aurum project, which clones the Boss OD-2 pedal's Turbo mode. The original OD-2 had a "Turbo" mode which could be turned on or off - this particular clone only includes the circuitry for that Turbo path. The non-turbo mode is not included, even as a toggle switch. The standard BOM also will build the OD-2r version of the pedal, as the volume control on the original OD-2 had to be pretty much cranked to 100% to get unity volume coming out of the pedal. The OD-2r fixed that issue, and that fix carries through to the standard Aurum build. That being said, if you want the original, AionFX calls out where parts should be substituted to build that version of the pedal.

As with many Boss pedals, this one is incredibly dense, and AionFX officially lists this as an intermediate build. There is no individual part that is tricky, but rather there is a very high component count - including no fewer than twelve transistors of three different types - including the 2SK209-GR transistors that you can purchase on adaptor boards for the SMD versions (photo below). Another unusual feature is the sheer number of 4K7 Ohm resistors used in the build. In many modern pedals, the 4K7 resistor is used as the LED current-limiting resistor to control its brightness, but in this build it appears all over the actual circuit as well (a total of 15 of them!). Needless to say, I had to solder the 4K7s as their own group!

During assembly, you have to be careful as the board gets very tight. Putting resistors and diodes in first, followed by film capacitors, then transistors, and finally electrolytic capacitors seemed to work to ensure there weren't awkward reaches - at least in setting the components. Actually soldering that tone pot down once all of the other components were installed around it was challenging!

Once again, the enclosure draws on the original to a large extent - including labels for the controls themselves. I'm working on a slightly updated version of this design that I may use when / if I sell a few of Boss pedals down the road. That being said, I'm not sure that this one would be a great choice. While I can make one for myself cheaper than I could buy one, these are fairly common pedals with price points starting at around $75 for one with both the turbo and non-turbo modes (though from what I hear most of these spend their time living in Turbo mode anyway). Mint copies run about $110 - so honestly I don't know if I could beat that price point.