History buffs will know that Boss launched what is considered to be the original OverDrive pedal the OD-1 - back in 1977. Boss applied for a patent on its circuit design which was then the rather new Asymmetrical Clipping configuration. Then Maxon / Ibanez launched their own competitor to that - the TS808/OD808 Tube Screamer - which had slightly softer Symmetrical clipping to Boss’s Asymmetrical OD-1.
Obviously the TS808 was a huge success - to the extent that Boss needed to come up with their own slightly softer OD-1 style competitor to that. And so the SD-1 was introduced in 1981. In essence the SD-1 has an almost identical circuit configuration to the TS808 - while there are slight component value differences - and of course the SD-1 has Asymmetrical clipping like its OD-1 forebear.
The SD-1 typically has a bit more volume, harmonics, and crunch. While as if you modify it and equalize the clipping to Symmetrical configuration it yields a touch more edge and drive than the TS808 but overall very similar really. With Asymmetrical Clipping applied it gets more volume, edge and harmonics than the comparative TS808.
There still seem to be mostly two firm camps of loyal adherents - for either SD-1 or TS808 varieties - while I celebrate them both! Historically famous users of the SD-1 include The Edge, Jonny Greenwood of Radiohead, and John 5.
My path to the SD-1 was very slightly different to the MT-2 - while I’ve ended up with the same result for the both of those pedals - just in different order of acquisition. My first SD-1 was actually the SD-1W Waza Craft Edition - which was released back near the end of 2014.
I then did an overview of key Keeley-Modded Boss Pedals - where my principal three were the BD-2, DS-1 and MT-2 - but then added a bonus round of the Keeley-Modded SD-1 - so then I had two varieties of that - and of course 3 including the latest one. The Anniversary Edition is an exact inversion of the SD-2 colours - where the original has solid yellow enclosure with black text, the inversion features solid black enclosure with yellow text - a really cool alternative variant to own in place of the standard edition.
Different players will each like aspect of the Standard, Keeley Modded, and Waza Craft editions - while it’s obviously the standard model which is the bestseller - it shouldn’t be too far behind the DS-1 and MT-2 in the sales stakes - actually - possibly pipped by the BD-2 too which most know by now is my favourite overdrive pedal of all time - admittedly in Keeley Freak Fuzz Modded Edition!
So if you like the TS808 - but prefer a little more bite, harmonics, gain and volume - then the SD-1 is your perfect candidate for that - and why not get it in a cool black enclosure!
The 40th Anniversary Inverted SD-1 Super OverDrive should be available at most key Boss dealers imminently - it is priced at €82 / £73 RRP - that edition’s production cycle is limited to 2021.