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YellowSquash Sound Labs IronFist Compressor Review

With a name like YellowSquash and Iron Fist you might assume this compressor device is an all out squash machine. While it is capable of squashing your signal and serving as a limiter it is so much more.

Notably, it can be a punch machine!

More on that later.




The IronFist is a 4-knob compressor/sustainer pedal with a built-in noise gate. The pedal works by making loud notes quieter (the compression circuit), and quiet notes louder (added sustain) with minimal altering of your original tone. There is no added distortion that is audible.


The most notable feature is the noise gate circuit which eliminates and audible noise that is quieter than the set threshold.


Have hum or hiss in your signal? The noise gate feature of the IronFist is for you.

The folks at YellowSquash suggest that to take full advantage of the built-in noise gate feature, the general recommendation is to place IronFist after your biggest noise contributors in the signal chain, but before any gain stages (things like overdrive, fuzz, distortion, etc) because these types of pedals tend to make any input noise much worse. The gate feature is quite remarkable and works very, very well.




Turn the Gate dial clock-wise to reduce or eliminate hum and hiss. Depending on how you have the other dials set, and what is ahead or behind the IronFist will determine how high the gate knob must be rotated. You will need to find the right balance as too little rotation (too far counter clockwise) will let noise through, but too much rotation (too far clockwise) will choke off the useful signal. It is a delicate balance but is so handy.


The Comp dial is more of an attack control. Rotated more clockwise brings on more squish. At first it seems fairly subtle, until you turn the pedal off and realize just how much squish was there. It's a very natural across the whole dial and is useful across the entire range unlike so many compressors that enter squash territory quickly or just feel unnatural.


As you rotate the Sustain dial more clockwise you definitely get more added sustain. Notes become longer. I'm not exactly sure how the Sustain dial functions though it feels a lot like a threshold control where settings to the left of noon allow more signal through before feeling clamped down.


Rotating both the Comp and Sustain dials to 3:00 or higher gets you into limiter territory. Again, it feel very natural. If you aren't a fan of limiting function, using the IronFist might change your perspective.


There is some dip and swell, but not overly dramatic.


The Volume knob is there for makeup gain and there is enough gain on tap. One thing to note is that the higher the Gate dial is rotated (more clockwise), the more Volume increase will be required.


The pedal has a soft knee feel and there is minimal popping sound on the attack, even at higher settings. Natural feeling is really the best way to describe it. At first I felt like the IronFist was a very transparent compressor, until I connected several other compressors in a line and compared. It's not that the IronFist isn't transparent, because it isn't colored in the sense that the Diamond or Forest Green compressors are colored, for example.


But there is this noticeable punch that is inherent to the pedal across the entire range of settings.

For example, put the Comp dial at 11:00 or noon and the Sustain dial at 10:00 - 11:00 and everything is just fuller, rounder, with more "umph". Very nice. It's not an EQ alteration like the tilt EQ of the tone knob on the Diamond, it is just always there. It's the goodness of a quality compressor that you miss when you turn it off.


There is minimal loss of highs and lows until you get into the more extreme squashing and limiting side of the pedal. With a more subtle setting, a low E or B on a bass will sound tighter and bigger at the same time, but not in an unbalanced way.


I really like this one. On the downside, the YellowSquash IronFist is not the most versatile of compressors. You don't have full control over threshold, input gain, and release, etc. There is no LED for threshold/gain reduction metering. I'd prefer having more control over release. This is personal opinion, but it isn't the most sexy looking compressor on the market but beauty is in the eye of the beholder.




The foot switch is the soft switch type and is true bypass taking the pedal completely out of the signal path.


Input and output jacks are top mounted as is the power input. Power requirements are standard 9 volt center negative barrel.




A blue LED illuminates when the pedal is activated. There is no gain reduction/threshold meter.




The enclosure itself has nice weight to it and is of high quality. The paint is black with a multi-color speckle. Depending on the light it will appear mostly black or with more light the glitter effect will come out more. It comes in a plain white box with user guide. The pedal is blanketed in a black felt bag.


There is room inside for a 9-volt battery.



If you are looking for sustain and something to smooth out your tone and add punch at the same time, look no further. The IronFist would make a great choice.

Prefer all out control of every facet of compression? Look elsewhere.


That said, the IronFist will deliver punch, smoothing of tone, evening out of dynamics, sustain, and a high level of squash/limiting. Not bad for a pedal that costs just $179 retail. That's not bad.




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