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Hands-On Review: Peterson VS-R StroboRack Virtual Strobe Tuner

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The most accurate rack tuner on the market

Dan Day
Musician’s Friend Staff Writer

WWJD—What Would Jimi Do? It’s a question that seems to occur naturally at some point to guitarists or music fans in general. How would Jimi Hendrix, if he were alive today, deal with the explosion of guitar-related technology that started not long after microchips began to be mass-produced? Jimi loved going to music stores and walking out with the latest gadgets such as the then-new wah-wah and Univibe. If you’ve listened to his concerts you’re all too familiar with his occasional bouts with tune-itis. With his exuberant whammy-bar playing and string bending he could have used a decent tuner to save time between songs. According to Peterson, Jimi’s road crew used a strobe tuner backstage before concerts, but Jimi did not use it onstage. I believe that Jimi would have eventually gone to a rack-based system; the tuner would have been something like the Peterson VS-R StroboRack Virtual Strobe Tuner.

Strobe: None more accurate

Peterson, the oldest electronic tuner manufacturer in the world, celebrates its 60th anniversary in 2008. Their latest triumph is the VS-R StroboRack—the most precise rack tuner on the market—with one-tenth of a cent accuracy. Because it uses a high-resolution display it is more sensitive and accurate than other types of tuners with LEDs, needle-type displays, and imitation strobe patterns that can do no better than ±1 cent. Which is OK but no match for the human ear. With no moving parts to wear out, the StroboRack uses Peterson’s exclusive Virtual Strobe Technology to continuously read the input signal in real time. Minute changes in pitch are displayed instantaneously in the scrolling image of the virtual strobe display at literally the speed of light. The image slows down the closer you get to the correct pitch; the strobe stops when your instrument is in tune.

If you’re a guitarist, this has probably happened to you: you’ve tuned to a perfect-sounding open E chord, but when you played the D chord it sounded off—especially the G and B strings. So you tune the D chord so the intervals sound perfect but now the E chord is off. Back and forth you go, twisting and tweaking until both chords sound OK but neither is perfect. You have stumbled, my friend, onto what musical experts call equal-tempered tuning, a compromise tuning scheme for fixed-interval instruments such as fretted instruments and keyboards. With equal-tempered tuning all of the intervals are just slightly out of tune (thirds a little sharp, fifths a little flat) so you can play reasonably in tune anywhere on the fretboard or keyboard in any key.

Of course, the StroboRack does equal-tempered tuning and does it well. The StroboRack also allows tuning in 11 historic temperaments useful for organ, harpsichord, brass, and early string instruments such as the lute and viola de gamba.

Peterson VS-R StroboRack Virtual Strobe Tuner

Sintonizzazione dolce

The StroboRack goes beyond temperaments with even more flexibility. What makes the StroboRack especially powerful are the temperaments that Peterson created and named Sweeteners. These are specially formulated tunings that are optimized for (relatively) modern instruments such as the guitar and have intervals that sound pleasingly resonant and pure, with no beats. In other words, they sound sweet. Being able to do your own professional guitar setups means the StroboRack will save you money. You can even make money doing intonation jobs for other musicians.

There are 23 Sweeteners programmed into the StroboRack for acoustic, 12-string, baritone, and pedal steel guitars. There are seven Sweeteners for electric guitars, basses, and 12-strings set up to use the Buzz Feiten Tuning System. The Peterson Sweeteners include a guitar Sweetener that makes fourth and fifth intervals—used in power chords—more consonant even when played through an overdriven amp. The acoustic guitar Sweetener provides useful compensation when a capo is used. It uses a unique stretch tuning that compensates for the human ear’s tendency to hear upper register notes as flat even though they are technically in tune. Dobro players, or players of any type guitar, have two Sweeteners to choose from for tuning to open A, D, or G. There is one Sweetener each for violin, viola, and cello, and there is even a Sweetener for the popular DADGAD tuning. If you have an unusual tuning that you’ve come across or developed your own Sweeteners, there are eight setting locations available to store your user-programmable tempered tunings.

The ins and outs

The StroboRack, a standard 1U rack-size unit with all-metal construction, is stompbox sturdy: you can put it on the floor and stand on it and not leave a dent.

Front and rear input Neutrik jacks accept a 1/4" TRS instrument cable. A front mute button activates the tuning mode. An optional footswitch to control the mute can be connected to a rear-panel 1/4" TRS jack. A rear-panel 1/4" TRS output jack connects to your amp or sound system. Six menu pushbuttons and a data wheel change the value of each menu selection.

A big advantage of the rackmount design is the large display. The part of the display that indicates sharp or flat tuning can be easily read from across a room. The entire display scrolls in either direction to indicate sharp or flat so you don’t have to stand right in front of the tuner to use it. When the tuner is in the non-muted play mode the display can scroll or flash a custom message such as your name or your group’s name. A built-in mic makes it possible to tune acoustic instruments and a reference tone output can be played back through an external amp/speaker.

If your amp or sound system uses balanced inputs or you would like to run stereo output, you can upgrade the StroboRack to accept any type of signal with the optional SR-EX Pro Input Expander. Its unique input configuration allows direct hookup for hybrid, balanced, and stereo instruments such as the Stick, electric guitars with piezo bridges, and basses or mics with balanced outputs. It has a combination 1/4" stereo/XLR input that automatically recognizes the type of input—1/4" mono, 1/4" stereo, or XLR—and routes it to the appropriate output. In auto mode, the built-in DI detects if a ground is present and automatically switches the signal ground. The Pro Module also lets you control Presets (the combination of a Sweetener and Drop Tuning value in half-steps) with an optional footswitch.

Peterson SR-EX StroboRack Pro Input Expander

In addition to the rackmount tuner, there are two other options. If you prefer pedals, the StroboStomp2 is the stompbox version of the world’s most accurate tuner. It has 22 Sweeteners for a variety of stringed instruments, plus four user-programmable Sweeteners. It has 100% true bypass switching to allow you to mute both the regular and DI outputs for silent tuning.

The StroboFlip has a compact flip design, large bright LCD, and full user programmability.

The Peterson VS-R StroboRack Virtual Strobe Tuner has the range and accuracy to handle any tunable instrument. With its array of exclusive Sweeteners and ability to store your customized tuning schemes, it can make your instruments sound even better. Its sturdy rackmount design with large display make it a valuable addition to your onstage or studio setup.

Features & Specs


  • 0.1 cent accuracy (within 1/1000th of one semitone -1/10th of one cent)
  • Concert A range: 390Hz to 490Hz (adjustable in 0.5Hz increments)
  • Range: 16Hz to 3.6kHz
  • Large, backlit Virtual Strobe display
  • Exclusive Sweetened tunings for electric guitar, acoustic guitar, bass, Dobro, baritone, pedal steel guitar, electric violin
  • 7 Buzz Feiten Tuning System presets
  • 8 user-programmable Sweeteners
  • 2 input jacks
  • 1 output jack
  • Built-in mic
  • Mute button footswitch jack
  • Reference tone output jack
  • Neutrik jacks
  • Rear 12V BNC output for optional gooseneck light
  • Built-in power supply (no wall wart)
  • All-metal construction
  • Weight: 5.7 lbs.
  • Dimensions: 19" x 1-1/4" x 8"

SR-EX Pro Expander (Optional)

  • Inputs: 1 combo TS, TRS, XLR jack (mono, stereo, and balanced), 1 DI input
  • Outputs: 2 TS jacks, 1 XLR jack
  • Controls: Ground lift switch
  • Channel switching options


  • 100% true bypass switching
  • Improved battery life
  • 22 Sweeteners


  • Compact
  • Large, bright flip-up LCD

Tags: Tuners

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