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 "High Range Chromatic Tuner". Additionally, the TU-3 Chromatic Tuner took the TU-2's existing functions and improved upon them by offering more tuning modes, and a greater calibration range. The original inspiration for the TU-3 were the original TU-12 and TU-12h. These tuners were housed conventional plastic enclosures that tuned using flat/sharp light indicators, and bouncing needles in-a-VU-meter-style. The TU-12/12h originally 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 Anderton's Music

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 six-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 Arrows

In addition to the Tuning Indicator (meter) described below, there are also two tuning arrows. One on the left side of the pedal face pointing right, the other on the right side of the pedal pointing left. If your pitch is flat, the left arrow will light up, telling you that the pitch needs to increase. If your pitch is sharp, the right arrow will light up, telling you to tune down.

© Copyright 2009, Boss Corporation. Reproduced here under Fair Use.

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

Per the original Boss-TU12 and -TU12h tuners, this method of tuning is the original. In this tuning mode, the lights in the Tuning Indicator act almost like a needle in a VU meter. The more extremely flat or sharp that the note that is detected by the TU-3, the further the light-indicator-needle will be from the center of the tuning indicator.

• If the light-needle on the meter is on the left side of the tuning indicator, the note played is flat and needs to be made sharper;
• If the light-needle is floating on the right side of the tuning indicator, the note played is sharp and needs to be flattened.
• Once and when the note played is in-tune, the light-needle will hover in the center of the tuning indicator. A couple of lights from each side of the tuning indicator will converge in the center of the tuning indicator, and the light of the indicator will change from red to yellow-green, indicating that the note is tuned properly.

"Stream" Tuning

While there is no strobe or strobe-simulator used by the TU-3 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 notes are tuned, the faster the lights on the tuning indicator will rotate. As the note gets closer to the correct pitch, the rotation of the lights will slow down.

• 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.

After having used either one of these tuning methods, the end result is the same: Your instrument is 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.

Sun-Glare Display

If playing outdoors in sunlight, it's possible to increase the LED brightness in order to see the tuning indicator despite possible 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

Regardless of whether the "Output" jack or the "Bypass" jack is used, this pedal does not invert phase, as this pedal only inspects the signal going into it. It's not an effect that will change the signal. This means no phase inversion from the TU-3

Schematic

The Boss TU-3 has no schematic that we've been able to obtain. The closest schematic that we've been able to muster is from a first-edition TU-2 manual (issued by RJA) from Japan. Since the circuitry for the TU-2 is an antecedent to the TU-3, we've included it to aid in possible trouble-shooting.

Assuming Fair Use. Copyright claims on TU-2 Service Manual are not to be found.

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