Published On: Fri, May 6th, 2011

Boss ST-2 Power Stack & PS-6 Harmonist

From the mighty roar of a big rig to crazed squeals and insane octave jumps, these two pedals from the faithful Boss are on the extreme side. Review by Martyn Casserly.

There’s something about the arrival of a couple of new Boss pedals that always warms the cockles of this reviewer’s heart, and in this weather we could all use some hot cockles. From the reassuringly the solid colours to the boxes hewn from purest hard, truly they are a place of refuge in the storm of life. Joining the none-more-boxy lineup today we have the ST-2 Power Stack & PS-6 Harmonist units, both of whom promise much in the way of sonic delectation.


With a name like Power Stack and the no-nonsense black livery, there’s no prizes for guessing the nature of this one. Essentially the ST-2 claims to give your combo the sound of a stack, without the need for roadies or the purchase of snug leather trousers. Controls are clear and simple with Level, Bass, Treble, and the all-important Sound. Whereas you might expect this to be your normal Gain control and in many ways it is the tonality also changes as you move through the three settings of Crunch, Drive and Ultra.


On a clean amp setting the Crunch adds a cool bluesy bite with a bit more oomph, great for those funkier Hendrix and SRV licks. There’s a subtle increase in the gain across the Crunch third of the control, meaning you can fine-tune the sound to taste before the Drive circuit takes over. Entering the Drive portion things get a bit spicy, with more overdrive and grunt available. Big Foo Fighters-type chords launch themselves from the amp with gay abandon, with a surprising amount of clarity retained for picking out individual notes in the chords. Dial in the Ultra and you’re away in metal land with enough chug and fizz to raise Cthulhu himself from his watery abyss. Using the pedal with an already driven amp results in even more aggression, and the ST-2 proves to be an excellent solo booster.


Now the name might sound a bit like a new-age life coach, but beneath the electric blue paintwork lies some rather clever circuitry. The controls on this pedal are far more complicated than the ST-2’s. Each of them serves more than one function, depending on the mode you are in. Balance adjusts the mix of dry and e? ected signal; Shift selects the pitch for the harmony (ie down or up an octave, third, fourth or sixth, etc); Key allows you to tune the harmony to the song you’re playing, and with Mode you can select whether it’s a minor or major.

Other options on the Mode control are for a Pitch Shifter (which you adjust using the Shift control), a Detuner (same again) and what will no doubt be the most used feature the S-Bend. If you’ve ever wanted to emulate the wild octave jumps of Tom Morello, Satriani or Vai but didn’t really want to buy a Digitech Whammy for the pleasure, then the S-Bend might be of great interest.

In S-Bend mode the pedal acts as a whammy-style control by always being o? until you press it, then it instantly bends the note you’re playing to either hilariously high frequencies or equally amusing low ones. Adjusting the Shift control alters where the pitch will go, with the Balance and Key dials now controlling the attack and decay rates. It’s hard to explain just how much fun this trick is, but we know that this feature alone will sell a tidy quantity of the PS-6. A word of caution, though: overuse of the S-Bend such as deciding to play every single solo with it will have your bandmates whacking you around the head with the nearest available chair at your next pub gig. You have been warned.

The Harmony mode itself is also seriously impressive. Once you’ve done the maths and worked out what key it should be in (this really isn’t a hit-and-hope sort of pedal) you’re rewarded with laser-pointed tracking for anything you can throw at it, and as the unit is polyphonic it can even handle chords with ease. Every mode is quality, and the accompanying manual helps make sense of it all.


The ST-2 is a great overdrive/distortion pedal that will beef up any weedy amp with stack-style tones. By itself it's cracking, but add an already cooking amp and you're in for a hell of a ride. For the more musically aware the PS-6 is an incredible pedal, with plenty of functionality, features and enough smileinducing charm to last for a very long time. Well done Boss... again.

Build Quality Playability Sound Value Vibe Score
18 17 18 17 18 88

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