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Third Man + Mantic Flex Review

Jack White’s fave phase-locked loop machine is a ticket to fuzzy fatness and synthy chaos.



Powerful, rich, PLL-driven synth- and fuzz-style tones. Awesomely unpredictable. Loud when you want it to be.

Twitchy controls. Terrifyingly unpredictable.


Third Man Mantic Flex


Ease of Use:



Jack White is a master of weaving ugly-duckling sounds into pop music’s vernacular. So it’s little wonder why he saw the appeal in Mantic’s excellent phase-locked loop (PLL) mayhem generator, the Flex. This new version is co-branded with Mantic and the name of White’s Third Man Records. But it marks a return to the design origins of the Flex, which has since evolved into a more complex variant called the Flex Pro. The Third Man version is the only way to get the original, simpler Flex. But while “simple” may be a useful descriptor for the relative number of controls, it does little to describe the many bizarre and demented tones and textures this circuit generates.

Gone Real Loopy
It’s something of a paradox that PLL circuitry can be responsible for such bizarreness in a guitar signal chain. In essence, a PLL is designed to lend stability to a signal by keeping waves from an input signal and a variable-controlled oscillator locked in phase with each other. They are used in many electronic applications and, among other things, are instrumental in helping you precisely dial in a radio station. In the world of sound synthesis, PLLs can generate steady, sustained output when using a constant input source—say, a sine wave from a keyboard. But the relative irregularity of a guitar’s input—brimming as it is with harmonics and string overtones—complicates the work of the PLL as it tries to keep the guitar input and VCO signals in phase. And when you mate that dynamic to the somewhat “ugly” sounds of a fuzzy square wave, the results range from chaotic to totally unpredictable.

Mantic’s PLL is unique. It’s not derived from the justly revered Schumann PLL that is the starting point for many stompbox PLL circuits. And in Third Man guise, the Flex’s control set is much simpler than the Schumann and many other PLL effects. The “lvl” is a master output (and man, is there a lot of volume on tap here). The focus control determines the range within which the waves can lock, but also feels and performs somewhat like an attack control on a synth. The pump, or VCO discharge control, enables you to tinker with the resistance between the VCO input and phase comparator, which destabilizes the PLL. The two toggles allow selection between short and long decay lengths, and fast and slower attack ranges.

Chaos Generator
It’s best to be prepared for strangeness and surprises when you hunt for sounds in the Flex. And it’s important to note that many sounds can be difficult to produce twice, given the highly interactive nature of the pump and focus controls, in particular. In this way, working with the Flex is much like interacting with an early modular synth.

Many settings are effective in A/B amplifier rigs, where you can devote one signal to the Mantic’s output and another to more conventional fuzz tones.

Nevertheless, there are several ranges where the pedal reacts in a generally consistent manner. With the pump and focus knobs all the way counterclockwise, a D played at the 12th fret on the fourth string will drop by an octave, taking on the fuzzy fatness of a keyboard synth. But nudge the pump knob up about 30 percent and the low octave disappears, replaced by a fast decaying fundamental that’s followed by a sort of fractured police siren tone that seems to rise in three or four glitchy, full-step intervals before dropping off a cliff. Move the pump up another 30 percent and the siren sound follows the fundamental in a fragmented full pitch-up, pitch-down cycle. With the pump control at maximum, you get an even smoother siren cycle. Though such sounds can feel beyond your control at times, you can manipulate the pitch shift in interesting ways with string bends and odd melodic intervals.

You don’t have to move the focus control much beyond its minimum setting before you begin to hear more fundamental note content and recover a measure of pick control. Interestingly, the best bet for preserving the melodic integrity of a passage (a curious motivation, perhaps, if you’ve elected to use this pedal in the first place) is to keep your picking active and the attack on the faster end of the pedal’s range. But there are also settings, usually with the focus and pump situated in the middle third of their respective ranges, where you can take advantage of Mantic’s buzzy, synthy fuzz voice without relying on eighth and sixteenth note picking for sustain. Many of these settings are very musical, if still unpredictable. But they are particularly effective in A/B amplifier rigs where you can devote one signal to the Mantic’s output and another to more conventional fuzz tones. (Mantic’s more “conventional” fuzzy textures are an especially cool complement to wooly Muff and RAT tones.)

In the up position, the “&” toggle activates a slower attack mode—strangling and filtering your note a bit. In the down position, you hear note fundamentals more immediately. The “$” toggle, meanwhile, dictates decay length. In the up position, notes linger longer. This setting is key to more conventional sustaining fuzz tones.

The Verdict
It’s important to reiterate that many of the tones described here can be tough to replicate exactly. And apart from the sensitive and interactive controls, differences in guitars, pickups, and playing approach can become tricky compound variables. But such unpredictability is half the fun of using the Flex. The complex and unusual sounds you can generate can pepper an arrangement in small but striking doses or underpin whole riffs. And if you have the curiosity to learn and understand the controls’ quirky interrelationships, you’ll uncover synth sounds and fuzz textures quite outside clichéd associations with either category.

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