Let me say that this pedal only sounds good on one setting (really) and only sounds INCREDIBLE with a Stratocaster/Fender Amp combination (really). This pedal is quite possibly the best kept overdrive secret in the world PERIOD.
When I originally bought one of these in 1994, I was looking for a Tube Screamer, or something similar. The store I went to at the time did not have any new or used Ibanez overdrive pedals except for the SD-9.
Well, I only had $70 in my pocket anyway, so I decided to try ALL of the used overdrive pedals available. There were about 11 or so there. Since it was closing time, the owner locked the doors and I proceeded to play all the overdrives back to back. The selection included original Rat and MXR distortions along with several Boss and DOD units. There was even an Electro Harmonix Little Big Muff. It took about an hour to play them all.
The verdict? The SD-9 blew them all AWAY. With a real bassy tone, a TS-9 vibe and just a hint of "fuzz", the SD-9 makes a Strat sound KILLER. I can't describe how good this pedal sounds.
The settings I use (and these are the ONLY ones that sound good) are:
Overdrive: 9 o'clock
Tone: 9 o'clock
Volume: Open ended
This pedal is real picky. With the tone turned up any more, it starts to sound thin. With the overdrive turned up more, it gets more fuzzy and extremely muddy. This pedal sounds flat out BAD with the settings on anything else but those listed above. My favorite is running this with a 4 x 10 Bassman and a Strat with a maple fretboard.
These pedals are still relatively cheap, but since some big players (including one of the Pearl Jam guitarists) have started using them (gee, I wonder why?), the prices have been on a steady incline. I actually owned four at one time! Aye carumba.