If you want to go all the way to 15, there's TurboBoost for the Les Paul Futura, SG Futura, Les Paul Classic, and Les Paul Signature. Switch out of bypass mode, and this onboard preamp can deliver a whopping 15dB of gain to overdrive amps, buffer your guitar from “downstream” effects, and drive inputs (like mixers and PA systems) that want a hotter level.
A standard 9V alkaline or rechargeable battery provides power, while the low current drain guarantees long battery life. But if the battery runs out of power, no problem—just bypass the preamp, and you're good to go. In fact if you leave the battery out, then the preamp bypass switch becomes a kill switch that's perfect for “stuttering” effects.
Most importantly, though, Gibson's engineers understood that any onboard preamp would have to sound as sweet as the straight guitar sound. That's why the preamp uses premium discrete components—not cut-rate integrated circuits—and is based on Field Effect Transistor (FET) technology, which most closely emulates tube amplifier transfer characteristics. (Translation for non-solderheads: it sounds smooth instead of harsh.)
The final touch is a trimpot adjustment inside the guitar's cavity that lets you customize the gain for your particular needs. Turn it up all the way when you want your leads to scream, back it off a bit for a big, beefy sound, or choose a gentle boost when you want the guitar to “speak” with more clarity.
The trimpot, circled in red, allows dialing back the preamp gain or maxing it out.
Although overdriving amps is an obvious preamp application, there are other ways TurboBoost can improve your sound. Long cable runs can rob your guitar's tone, and TurboBoost isolates your pickups from cable loading. This prevents “dulling” and is particularly helpful in preserving the shimmering highs of single-coil sounds (all guitars with TurboBoost can switch their pickups to single-coil mode). Overdriving compressor and sustainer inputs can increase compression, and if you want to use a Y-cable to feed two amps (or an amp and mixer for re-amping in the studio), the TurboBoost allows driving several inputs at once.
Sure, going up to eleven is fun—but why not go up to 15 when you need it?