BOSS TU-3 Chromatic Tuner — The World's Best-Selling Stage Tuner

The BOSS TU-3 Chromatic Tuner sets the standard for stage tuning reliability. Built on decades of BOSS tuning technology, it combines a sharp 21-segment LED meter, pinpoint +/-1 cent accuracy, and a road-tested all-metal chassis into the most trusted compact tuner pedal on the market.

The TU-3 covers an extraordinary tuning range from C0 to C8, supports 7-string guitars and 5-6 string basses, and offers multiple flat-tuning options for down-tuned playing styles. The High Brightness mode ensures clear readability under direct sunlight, while the Accu-Pitch Sign function provides an unmistakable visual confirmation the moment your instrument is perfectly in tune.

A built-in DC OUT jack lets the TU-3 serve double duty as a power supply for other pedals on your board. With buffered bypass to preserve signal integrity and compatibility with the full BOSS PSA adapter family, the TU-3 is an essential, always-on foundation for any pedalboard.

Key Features

• +/-1 Cent Accuracy: High-precision tuning detection ensures you're always spot-on, whether on stage or in the studio.
• 21-Segment LED Meter with High Brightness Mode: Crystal-clear readability even in direct outdoor sunlight; brightness is user-adjustable.
• Accu-Pitch Sign Function: The entire meter flashes when tuning is confirmed, giving instant visual feedback without staring at the center needle.
• Wide Tuning Range (C0-C8): Covers everything from the lowest bass frequencies to the highest guitar harmonics across all standard and extended-range instruments.
• Multiple Modes for Guitar and Bass: Chromatic, Guitar (with up to 6-semitone flat), and Bass (with up to 3-semitone flat) modes support 7-string guitars and 5-6 string basses.
• DC OUT Jack for Daisy-Chaining: Powers additional pedals directly from the TU-3, reducing the need for separate power supplies.
• Silent Muting on Engagement: Engage the tuner for completely silent tuning between songs.
• Buffered Bypass: Maintains signal strength across long cable runs.

Technical Specifications

• Tuning Range: C0 (16.35 Hz) - C8 (4,186 Hz)
• Reference Pitch: A4 = 436-445 Hz (1 Hz steps)
• Tuning Accuracy: +/-1 cent
• Tuning Modes: Chromatic, Chromatic flat x2, Guitar, Guitar flat x2, Bass, Bass flat x3
• Display Modes: Cent mode, Stream mode
• Nominal Input Level: -20 dBu
• Input Impedance: 1 MΩ
• Nominal Output Level: -20 dBu
• Output Impedance: 1 kΩ
• Recommended Load Impedance: 10 kΩ or greater
• Controls: Pedal switch, MODE button, STREAM/CENT button
• Indicators: 21-segment LED meter, CHECK indicator (battery check function)
• Connectors: INPUT jack (1/4" TS), OUTPUT jack (1/4" TS), BYPASS jack (1/4" TS), DC IN jack, DC OUT jack
• Power Supply: Carbon-zinc battery (9V, 6F22) or Alkaline battery (9V, 6LR61); AC adaptor PSA series (sold separately)
• Current Draw: 20 mA (standard); 80 mA (High Brightness mode)
• Battery Life (Carbon-Zinc): Approximately 5 hours
• Battery Life (Alkaline): Approximately 21 hours
• Bypass Type: Buffered bypass
• Width: 73 mm (2-7/8 inches)
• Depth: 129 mm (5-1/8 inches)
• Height: 59 mm (2-3/8 inches)
• Weight: 390 g / 14 oz (including battery)

What's In The Box

• BOSS TU-3 Chromatic Tuner
• Carbon-zinc 9V battery (6F22)
• Leaflet "USING THE UNIT SAFELY"
• Information sheet