Stomp King SK-7 Chorus Freeware VST Effect

Bob Leggitt | Sunday, 23 September 2012 |

New for autumn 2012, the Stomp King SK-7 is a great virtual stereo Chorus pedal, evoking memories of some of the rich and intricate vintage modualtion sounds of the 1970s and early 1980s. The SK-7 differs markedly from the SK-2 Sympho, which is also a chorus, but is designed to produce a more sophisticated, symphonic effect, as opposed to the SK-7’s fat, retro, analogue type sound.

The SK-7 is actually a dual chorus. So rather than simply duplicating the input signal and modulating the duplicate, the device creates three additional signals. It then runs the total of four signals (including the original input) as two pairs – each pair generating its own chorus effect. The modulation times of each separate chorus are automatically staggered. Therefore, however you set the Rate control, the second pair of signals will always have a proportionally faster modulation rate than the first. This drastically increases the complexity of the tonal animation when both choruses are running and beating against each other. The stereo image adds a wealth of spaciousness to the full, evolving sound.

You can choose either to hear the pure chorus effect of a single modulated pair, or the much lusher and richer sound of the dual chorus arrangement. I’ll explain how that works in the parameter descriptions below…

The SK-7 Chorus has three parameter knobs. A Rate, a Depth, and a Thicken. The Rate simply increases or decreases the modulation speed. Because both incorporated choruses are programmed to run at different speeds, the Rate will adjust both proportionally, but will not alter the staggered effect.

The Depth increases the width of the modulation, and thus the intensity of the chorusing. Higher Depth settings will create a more pronounced and obvious chorus.

The Thicken control is actually a volume knob for the second chorus unit. With Thicken set to 0, the second chorus is inaudible, so you get a pure chorus effect in keeping with a standard stereo chorus pedal. As you increase the Thicken value, you increase the volume of the second chorus. The sound gets thicker and a lot more complex. There’ll also be a boost in volume because you’re adding extra components to the signal. If you feel the need, you can compensate for this extra volume by reducing the volume slightly on your VST mixer. However, the volume increase is not dramatic, and to me it feels natural for the volume to be slightly higher when the full effect of the twin modulation circuits is active.


Your own ears should always be the judge of what’s right and what isn’t, but you may find some of the following guidelines useful… The effect is designed so that it’s very difficult to get a bad sound. However, if you set the Rate at a high level, you’ll probably find you want to back off the Depth. This is something which applies to chorus units in general. High Rate and high Depth settings tend to produce an exaggerated sense of pitch modulation, which can sound unnatural. Conversely, with the Rate set lower (below 40), you may want to use a higher Depth setting to keep the sense of spaciousness.

The Thicken control relies on both the Rate and the Depth (but particularly the Depth) for its effectiveness. Remember, the Thicken control is progressively adding in a second chorus effect, whose rate and depth is controlled by the Rate and Depth knobs, just like the first chorus. So if you set the Depth very low, when you add in the second chorus using the Thicken knob, you’ll only be adding a very shallow effect. Hence, the sound won’t get anywhere near as thick as it does when the Depth is set high.


Hopefully, all that makes sense. But here are some example settings to give an idea of what to expect in practice…

Rate: 45, Depth: 80, Thicken: 80… A rich and powerful chorus sound with a huge amount of movement in the sound. This is ideal for thin-sounding instruments. Even the plainest, cheap organ sounds should take on an interesting and engaging quality.

Rate: 100, Depth: 55, Thicken: 0… A classic ‘70s style chorus with a slight sense of wavering pitch. Very multi purpose as far as instrument types are concerned. This sound isn’t as fat as the one above, and has a slightly cheesy personality which some old chorus units seem to exude.

Rate: 10, Depth: 20, Thicken: 100… Using the chorus almost as a phase-shifter. The phasing of the split signals changes as they work through their cycles, and without much in the way of pitch modulation, you hear something like a cross between a phaser pedal and the old 1960s tape flange effect.

Rate: 29, Depth: 100, Thicken: 20… A really attractive deep standard chorus with just a touch of extra complexity from the second chorus circuit. The second ciruit, modulating at a different rate, has a smoothing effect on the sense of shifting pitch, and gives spaciousness without any hint of cheesiness.


To download, click the download link at the bottom of the page. You'll get a .dll file of between 2 and 3 megabytes.

Place the .dll file in your VST Plugins folder, and when you start your VST host it should detect the new software. If you normally have to add your VST instruments and effects manually, you’ll need to use the same process here.

Please be aware that the Stomp King effects are home-made products, released as freeware, with no guarantees of any kind. Every effort is made to ensure that the effects work well and enhance your recordings. However, they cannot be tested on a wide range of systems, and therefore there exists the potential for problems. In downloading, you agree to absolve Planet Botch of all responsibility should a problem of any kind arise as a result of you downloading, installing and/or using the .dll file. 

Once the effect is installed, simply switch on the SK-7 by clicking its On/Off stomp component, then use the three parameter knobs to adjust the effect to taste. The SK-7 has digital readouts under its parameter knobs, allowing you to note your settings (and perhaps pass them on) when you dial in a combination you really like.

Download the Stomp King SK-7 Chorus

The rest of the range is available via the main VST FX Download Page.

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