Boss SD-1 Super Overdrive Plus

riktig bild och ljudfiler kommer... The Boss SD-1 is probably one of the most known pedals on the planet, but at the same time it has always been something of an outsider. It has always stood in the shadow of the Ibanez Tube Screamer (even though the SD-1 has been in production continously since its introduction, while the Ibanez offering has floundered a bit), and the truth is that its circuit is very close to the TS-9. There are a few differences here and there, but overall it is extremely similar. And just like its green sibling, the SD-1 suffers a bit in the low end - some would argue even more than the Ibanez. Boss based the SD-1 on the OD-1, and it shows - it has more gain than a tube screamer, and a slightly dryer, raspier sound. Unfortunately, the sound is also a bit boxy and distant - it definitely has room for improvement!

One thing that makes the SD-1 extra attractive to use as a base for modifications is of course its low cost - you can buy a brand new pedal for less than half the cost of a reissue TS-9. For quite some time now, I have therefore wanted to make something out of the SD-1, and after trying a number of different variants (full-on 808 mod, 808 with twice the gain range, a booster version among others), I decided it was time to put something proper together. So... here's my version of the Boss SD-1. I call it the "Super Overdrive Plus", partly because it was the best I could come up with , but also because it is something of a three-in-one pedal, with more than just one trick up its sleeve.

The modification

As always, I start out by replacing the stock LED for a larger superbright yellow one.
The output section is then modified to TS-808 specs, which opens the sound up a bit.
The input section is modified for an increased input impedance, which gives the pedal a slightly clearer sound in the bypass mode as well.
A number of capacitors are replaced to give the whole circuit better bass response, change the response of the tone control and to smooth out the distortion.
The silicon diodes that generate the distortion are removed and replaced by a separate circuit board that contains three separate sets of clipping diodes (see below).
A three-way switch is then installed below the drive knob, giving you access to the following settings:

left	center	right
4 silicon diodes for symmetrical clipping with slightly lower compression than stock.	2 LED's provide very low compression and a very high output level.	2 Mosfet transistors provide a highly compressed sound with long sustain.

And the result?

The modified pedal is a very versatile creature, that can handle most playing situations. With the switch in the center position, you have yourself a clean-to-slightly-dirty booster with lots of output. Turn the gain/drive knob up, and you will enter the heavy blues -> AC/DC territory. Flip the switch to the left position, and you have a fairly traditional overdrive (slight mid-boost and all), with good dynamics and a firm, not very buzzy tone. And finally, with the switch to the right, you get maximum sustain and lots of compression for solo playing and rock distortion (hint: this mode works best with cleaner amp settings).

Watch out for volume jumps when you switch modes - a level knob setting that provides a reasonable output level in the mosfet mode (switch to the right) will be quite a bit louder with the switch in the left position, and extremely loud in the center position. Make it a good habit to always compensate with the level knob when you switch modes - preferably before you start playing. (Naturally, just because I wrote that you will instantly want to check exactly how big the difference is... oh well, consider yourself warned! )

Price:

400 SEK / 44 EUR

Prices do not include shipping.