From Analogman:

We modify the Boss SD-1 Super Overdrive to basically Ibanez TS-808 specs, including the chip. This is the yellow pedal, not the orange DS-1 Distortion. The yellow SD-1 has the same basic design as a Tube screamer but with asymmetrical clipping. I can leave the clipping as-is (Boss style asymmetrical clipping) if you wish, but I normally change it to the Ibanez (symmetrical) style on my standard SD-1/808 mod. Ibanez told me that Roland (Boss) has a patent on asymmetrical clipping, which gives it a bit more volume, harmonics, and crunch. With Ibanez style clipping, it sounds very much like a TS-808, but still has a touch more edge and drive available. With Boss style, it gets yet a bit more volume, edge, and harmonics. The Brown option is standard on the SD-1 as it really helps to smooth out the sound.

Our is also available on the SD-1/808, by customer demand. I thought the silver mod would be too expensive for this pedal but people really like the Boss pedals (they are more reliable than the Ibanez). FROG from Elderly Instruments was the 1st, as his TS9/Silver switches were failing too often, so he requested the SD-1/808/Silver. He likes them a lot, so we have been doing more silvers for other people. We now install a super bright GREEN LED for this FROG mod (looks cool too!!). I miss Frog, I used to hear from him every several months when his TS9 switches would die, now he never calls...

Please see all pics for condition. This one has no rubber on bottom (great for the velcro users) and one screw is broken off in the casing - obviously does not affect function

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