Treble Setting: Don't reflexively leave your Treble setting at noon, as a lot of players seem to do with tone controls on their pedals. The Treble control is capable of providing subtle gradations in high-frequency response and is usable and natural-sounding throughout its entire range; trust your ears, and use the control.
Output Setting: To use the unit as a true overdrive - hitting whatever follows it in your signal path harder than your straight-through signal would - your Output setting will almost certainly need to be above 10:00. Different amps and pedals have different input-stage headroom characteristics, so take some time to experiment with the Output to find whatever setting gives you the best results with your particular setup; often settings in the 11:00 - 1:00 range work well.
Clean-boost Mode: With the Gain control at its minimum setting, the unit is in clean-boost mode. In this mode the circuit has enormous headroom and will not generate any distortion of its own. Clean-boost enables you to hit the front end of your amp harder, or the next pedal in your signal path harder, without changing any of the essential characteristics of the signal the unit received - instant same-pickups-but-hotter capability.
Slide Switch: The output of the unit's predecessor, the Centaur Professional Overdrive, was buffered, an effective solution to the problem of signal degradation due to cable capacitance. This unit, informally named the KTR, allows the user - via the switch - to choose between buffered output or so-called true-bypass output the former almost always yields a signal with more presence than the latter.
Outboard Power: Most regulated 9-volt power supplies should work fine. Do not attempt to power the unit with more than 9 volts, as damage to the circuitry will result, necessitating the replacement of the entire circuit board; please note that this kind of damage is not covered under the unit's warranty.
Battery Power: As it did in the original Centaur, the standard Duracell Coppertop works well and sounds good in the KTR as well, so use that particular battery if possible. Expect about ten hours' life from a new Duracell; replace the battery whenever you hear a loss of dynamic range, a high-pitched tone (the symptom of a very weak battery), or anything else out of the ordinary.
Velcro: Standard inch-wide Velcro along the very top and bottom edges of the unit's die-cast bottom will neither hide nor harm the screen printing.
Warranty: Three years, parts and labor, to the original purchaser with no evidence of abuse or attempted modification; please keep your sales record.