The Tubescreamer TS-9 and the Boss SD-1 are both very similar and popular pedals and are essential for most blues, rock, indie, and metal artists. The popular 808 mod gives a warmer classic tone with the JRC4558 chip upgrade. The two channel mod installs a second footswitch to change from channel 1 to channel 2. Each channel has independent drive and volume knobs. The LED changes from Red to Green depending on which channel you are on and turns off as usual when bypassed. The added channel has extended range for a bit more gain. Two channels in on convienent package. There are two toggle switches available, one is bass the other is compression. The left one has three settings: to the left is loud crunchy gain like a tube amp breaking up; the center is a HUGE boost with some added grit; to the right is the stock compressed setting. The right toggle has three settings as well: to the left is a slight bass and gain boost which compensates for the huge bass cut this pedal has; center is the stock setting filled with mids; to the right is a HUGE bass boost that will add thumping lowend.
Two channel Mod: $65
Bass switch: $30
Compression switch:$30
TS808 Mod: $25