The ST-300 (released in February of 2016) builds upon the sterling reputation of the ST-200! It’s hard not to gush over this ground-breaking pedal from Sonic Research. Even a casual internet search reveals the Turbo Tuner to be one of the most highly regarded tuners on the market. It’s easy to see why: — ACCURACY — The Turbo Tuner is simply the most accurate pedal tuner on the market today. Each Turbo Tuner is individually calibrated at the shop to an accuracy of ±1ppm, which is about .0017 cents. The “official” ±.02 cent value listed on the spec sheet takes into account the drift with component aging, so that 20 years from now the tuner will still be within .02 cents (which works out to be ±.005Hz at 440.000Hz) —SPEED— The Turbo Tuner grabs the note almost instantly, without the annoying lag common in lesser tuners. —TRUE Strobe Display— Other tuners on the market feature a display that is generated by a microprocessor. The display on the Turbo Tuner is a TRUE stroboscope since the LEDs are driven directly by the analog input signal. What you see on the display is a direct visual comparison of two frequencies: one being the musical note you wish to tune, the other a precision reference frequency. For those of you that like to work on your own guitars, a true strobe tuner allows you to accurately set the intonation on your guitar! Other Features: The output of the ST-300 is muted when the tuner is on, and when off the input signal is passed directly to the output. It is completely disconnected from all internal circuitry and the tuner puts zero load on the signal. Extreme Accuracy The internal timing generator is calibrated at the factory to maintain a precision of ±.02 cents. Chromatic Mode Permits tuning to any of the 12 notes from C0 to C8, in any temperament. Open Tuning Modes Tunes to preset or user defined tunings. In this mode the tuner only recognizes notes that are defined for the specified tuning. The tuner comes with a number of pre-defined tunings for stringed instruments. These can be edited by the user. Power On Restore The ST-300 remembers the settings for mode, drop tuning and A4 changes. No battery is necessary. Flat Tuning Lowers all pitches up to six semitones. Reference Pitch Change By default, the tuner uses A4=440Hz as the reference pitch. This can be changed in increments of .1Hz, over the range of 300.0 Hz to 599.9 Hz. Temperaments The ST-300 can operate in the equal temperament or any 12 note temperament the user desires. The ST-300 can store a total of 5 different temperaments, in addition to the equal temperament. Battery or External 9 Volt Operation The Turbo Tuner ST-300 can operate for 12 hours continuous from a standard alkaline battery. This is enough for about 1,000 tune ups. It also works with any 9 Volt adapter designed for stomp boxes.