Screwdriver (700 +/- made)(ZoSos and Lucky Charms are screwdrivers)(Tonebender derivative? Modded Fuzzface with Treble Booster input?)(released when? – #4 dated 10-10-05)(retired 10-12-11)(A few units got “Smokey Mods” to balance some early treble issues)(How many made?)(Highest known number – )

Typical 3-knob Screwdriver, additional trimpots are on each side of the pedal
Marc's Screwdriver origin story (Via TGP):?

"I did have the basic building blocks of a Tone Bender in mind when I designed the Screw Driver. For a long time I had used a homebrew Fuzz Face as my primary dirt. Then I made a Range Master and used that as my #2 dirt. Then I noticed a magic happening when I stacked them. Then I noticed that the Tone Bender schematic uses a similar idea (there are many versions, but 2 of them are like a Fuzz Face and a Rangemaster combined--the two different versions differ mainly in the order in which the building blocks are combined). So my prototype idea was to combine the two into a fuzz and have the order switchable. But playing with the idea opened up lots more areas of inspiration and convinced me I didn't need to worry about switching order. I decided to focus in on the awesome overdrive tones instead of fuzz. Lots of evolution and constant tweaking eventually got me to the Screw Driver in its current form. It still resembles some of the lighter tones of a fuzzface or a tonebender; the kind you get with the guitar volume rolled back."

Long story short, the Screw Driver was invented to do 2 things:
1) Get a Pagey sound, but using a Strat
2) Get all those cleanish, in-between tones you could get by using a Fuzz Face with your guitar volume rolled back, only without needing to fiddle with the guitar volume.

The SD doesn’t clean up as quickly or suddenly as you roll down the guitar volume. But that’s kind of the point. With some Fuzz Faces, you are at fuzz on 10, overdrive on 8, and clean on 7. Also, the SD rolls off a bit of treble as you turn down the guitar volume. I actually did not design the SD to work well with the guitar volume but rather to sound exactly how you would want it to sound but with the guitar volume full up. The idea was “just step on it” and not have to fiddle with your guitar volume. (I was having trouble dialing in just the right overdrive sound before the beginning of a song using a fuzz, so I designed the SD to have that sound on tap.)

I did, however, design the HFD and the HOD to work well with both humbuckers and with the guitar volume, since a Les Paul is typically played in terms of varying the volumes on the pickups, and that’s an essential part of designing something to work well with humbuckers.

First Screwdriver Top
First Screwdriver Guts and Plate
Courtesy of Marc Ahlfs, he decribes this image as: “experimental prototype of what was the basis for the Screw Driver circuit”
Quite literally, the FIRST Screwdriver, courtesy of Marc Ahlfs: ” The first actual Screw Driver, before the trimpots were added”