http://www.olaenglund.com
These are distortion pedals to be used in front of a amp with a clean channel input. Unlike the Legend amp series that are actual pre-amps.
S-Drive : 0:10
B-Drive : 2:23
P-Drive : 4:38
E-Drive : 6:35
For more info check: http://www.amtelectronics.com/products/drive_series_effects/