TU-3

Boss TU-3 Chromatic Tuner. The TU-3 is an advancement the previous TU-2. The TU-2 was itself was a reimagining of the Boss TU-12h Chromatic Tuner, which in turn was from the Boss TU-12. The TU-12h was not a pedal, but a conventional tuner that used a bouncing needle-in-a-VU-meter that was housed in a plastic case. The TU-12/12h could fit near the handle area of the Boss 6-pedal-unit, the BCB-60. These previous electronics served as the platform on which the Boss TU-2 pedal was built, and in-turn the TU-3.

Boss tuning device release dates

• 1982: TU-12 Chromatic Tuner unit
• 1990: TU-12h High-Range Chromatic Tuner unit
• 1998: TU-2 Chromatic Tuner pedal
• 2010: TU-3 Chromatic Tuner pedal

Controls

Image from Google Express

• Button 1 - "Stream / Cent": At first glance, this button toggles between "Stream" and "Cent" tuning methods, but there's a lot more functionality described below.
• Button 2 - "Mode": At first glance, this button toggles between
  • Tuning for Bass or Guitar
  • Setting the number of steps or half-steps below standard tuning you may wish to tune your instrument
• Footswitch 1 - "Active/Bypass": Toggles the function of the pedal between "on" and "off". How this footswitch works is dependent on the output jack used.

Jacks

• Output 1 - "Output": When this output jack is used, toggling the footswitch will turn the signal on or off. The signal will be "on" for when the tuner is not engaged or in use, and the signal will be "off" when the pedal is being used to tune. Use this when you don't want people to hear you tuning up.
• Output 2 - "Bypass": When this output jack is used, using the footswitch on the TU-3 only turns the function of the tuner on and off. That means that whether the tuner is on or off, the instrument signal will always be going out on this jack. Use this when you don't care about people hearing you tune up.

• Power In - Standard 9-volt barrel-negative tip Boss-style power supply
• Power Out - The TU-3 *can* power other pedals if using a daisy-chain cord of Boss-style barrel-negative tip terminals, provided those other pedals use the same AC adapter

Note

There's nothing stopping a musician from using both output jacks at the same time. For example, it would certainly be possible to use the Bypass jack as a "direct out" for re-amping while using the Output during a live concert.

Bypass:Buffered

Like all Boss pedals, the TU-3 has a buffered bypass.

General Information

The TU-3 begins at power-on in the "Chromatic" mode for tuning. Using this mode is simple enough: play a note, and the pedal will detect the note, and show which note is being played in the digital display. Pressing the "Mode" button at that point will advance right-to-left through the different tuning modes, as seen printed under on Tuning Indicator.

The TU-3 can handle tuning seven-string guitars, and 6-string bases.

1. In Guitar mode, a musician can press the mode button again to select drop-tunings, all the way to 6 half-steps down.
2. In Bass mode, a musician can tune down by 1 to 3 half-steps.

Tuning Indicator

The Tuning indicator is the LED-filled arc seen spanning the face of the pedal above the digital display showing the note pitch. There are two tuning modes and both work well, they're just configured differently to cater to different player preferences.

"Cent" Tuning

In this tuning mode, the lights act in a manner corresponding to a needle in a VU meter:

• When a note played is

Stream Tuning

While there is no strobe being used to pitch-match, in this tuning mode, once a note is sounded, the lights in the tuning indicator behave like a strobe tuner. The flatter or sharper that the notes are tuned, the faster the lights will rotate. As the note gets closer to the correct pitch, the rotation of the lights will be slows.

• If the lights rotate clockwise when your note is played, then the note is flat and needs to be tuned sharper;
• If the lights rotate counter-clockwise when the note struck, then the note is sharp and needs to be tuned flatter;
• Once and when the note is tuned to pitch, the lights will all briefly halt and then converge at the center into non-moving yellow-green light indicating correct note pitch.

You're tuned!

Tuning Calibration

By pressing both buttons at the same time, it's possible to reset the tuning calibration of the TU-3. Default calibration is A=440, but the calibration can be set as low as A=436 and as high as A=445.

Additional Tricks

If playing outdoors in sunlight, it's possible to turn up the LED brightness in order to see the tuning indicator despite sun glare. Hold down Button 1, the "Stream / Cent" button for 2 seconds. The tuning indicator section will briefly display 5-6 vertical bands to indicate you're in high-brightness mode. To revert to standard brightness, hold down Button 1, the Stream / Cent button, again for two seconds, and the TU-3 will again display the tuning indicator in standard brightness.

Pedal Manual

https://static.roland.com/assets/media/pdf/TU-3_e04_W.pdf

Phase Inversion: No

Given that the note going out the "Output" jack is the same as the note going out the "Bypass" jack, it's easy to determine that this pedal does not invert phase.

Schematic

The Boss TU-3 has no schematic that we've been able to obtain. The closest schematic that we've been able to find is from the TU-12h. As previously indicated, the circuitry for the TU-12h is an antecedent to the TU-2, and therefore the TU-3. We've also included some PCB images if anyone is interested in creating an accurate schematic.

Artists

• Nuno Bettencourt
• Chris Cornell
• Billy Duffy
• Marty Friedman
• Paul Gilbert
• Scott Gorham
• Dave Grohl
• James Hetfield
• Gus G. (Konstantinos Karamitroudis)
• Johnny Marr
• J Mascis
• Duff McKagan
• Dave Navarro
• Nick Oliveri
• Buzz Osborne
• John Petrucci
• Matt Pike
• Alex Skolnick
• Slash
• Michael Sweet
• Steve Vai
• Brad Whitford

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Additional Sources

• http://equipboard.com/items/boss-tu-3-chromatic-tuner