Info from the manufacturer about the original:
The Signa Drive can go from a clean boost all the way to a Marshall crunch and every thing in between. If you are looking for a very versatile OD this is it. I am very proud of this pedal.
This pedal is so good, it most likely will replace both the Tubeslammer and the Tubeslammer Deluxe!
Updated 4th September 2014 - new compact layout added