(Originally written by masstoman/translated from Audiofanzine FR)
Square wave tremolo (chopper) + classic tremolo effects (sinus or triangle, I don't know exactly). Both effects work independently or simultaneously when you use the unit in stereo mode. The speed of each tremolo can be controlled either with an expression pedal or with a classic rotary control (and the pedal only has an on/off function). The chopper square wave impulse width can be adjusted with a ratio control for effects ranging from wide tremolo to machine gun shots. A depth control adjusts depth/intensity of the classic tremolo for effects ranging from light tremolo to a tremolo with silent phases
The circuitry is fully analog with digital control.
The unit offers a Midi input for tempo sync with a Midi clock signal.
It has also one audio input and two stereo outputs (also usable in mono mode).
The configuration is simple and quick, effects immediately sound good and you can adjust the effect's speed with the expression pedal. It's fun to find the right speed with the foot. The action is smooth and responsive. It can produce strange and inspiring results. You can adjust the stiffness of the expression pedal.
The unit works good in Midi sync mode and it has an immediate response to tempo changes. If you tune the tempo changes in your sequencer and choose a high ratio setting to get very short impulses, you will even get chopping sequences. Coooool!
The effect develops its full dimension in stereo mode. The chopper springs from left to right, very exciting! In stereo mode, the classic tremolo effect is like a panner which progressively sends the signal from left to right as if you were playing with the pan knob of a mixer. This way, you can use both effects at the same time. Listen to the sound demos on the manufacturer's website, they are very eloquent.
The chopper produces an organic sound especially when you take the time to carefully set the impulse width to get the desired square tremolo effect. Although it produces a sharp sound, the effect has not such a hard attack as the one provided by other square tremolo effects. I don't know if it's the result of the analog circuitry but I love it.
When the effect is on but without a signal you'll hear a high-output noise (pop) on time (it's probably the impulse of the chopper square wave). But it isn't annoying. And if there is no signal, you can simply switch off the effect! And then the unit becomes exceptional. It's a strange statement but you'll discover one of the advantages of the unit when the effect is turned off. It's simply as if the pedal wouldn't be present anymore but your mono guitar signal becomes stereo. I play a Gibson Flying V equipped with high-output level ceramic pickups and I haven't noticed signal loss. It's simply transparent. I didn't know that I had also bought a stereo splitter! Excellent for dual amping applications!
IMO this is the best and most comprehensive product of its kind. Awesome audio quality. Maybe I'm really enthusiastic because I've only used it one week... but honestly... wow!
I looked for sequence tremolo/filter effects with tempo sync for a long time and I first bought the Roger Linn Adrenalinn III. Although it is well conceived it wasn't that convenient. With high output levels in an overdrive channel, I could hear the digital stage making a sort of overloaded-HDD noise. And I noticed signal loss when the effect was turned off. I plan to buy the Mega-Wah and couple it with the Pro-Chop to get huge modulation effect possibilities!
I only want to add that the staff at Gig-Fx are very responsive and nice. I sent them technical questions before buying it and the boss immediately answered me. They also responded to my (very positive) feedback.