£184, www.intensivecareaudio.com

The last thing some of us want to be reminded of when we’re making music is blood, pain and hospitals. But there’s no denying the quirky appeal of Intensive Care Audio’s medical-themed pedals, designed for the treatment of what its maker calls Bland Guitar Syndrome… and the Vena Cava Filter might just be the most powerful blandness-obliterator of the lot.

• READ MORE: Ritual Devices Grimalkin review: an ultra-wild fuzz that’s never knowingly sensible

‘Filter’ is a word with many meanings, but in this case there are two points to bear in mind. One, it’s a dynamic auto-filter, so the tonality of your guitar will shift around to a fixed pattern as you play; and two, it’s combined with a high-gain distortion circuit and a ring modulator. On paper at least, that adds up to some pretty fruity sonic concoctions.

It’s a black wedge but nobody’s going to mistake this for an old Shin-Ei fuzz box, mainly because it’s got more controls than an X-ray machine: six knobs, a large eight-way rotary switch, two toggles plus a pair of footwitches each fitted with a custom topper.

Let’s look at that rotary switch first, because it’s probably the most important bit of the pedal. This is for selecting the LFO mode – that is, the shape of the up/down tone-filtering waveform. There are a couple of randomised options here, plus a standard sine wave, some ‘stepped’ effects and more. Be a patient patient – I will go through them all.

The right-hand footswitch is for tap-tempo, while the toggle switches let you mess with the ring modulator and the filter’s tonal range. The rest is fairly straightforward, including a blend knob for the filter circuit and just one control for the distortion, setting its gain.

What does the Vena Cava Filter sound like?

The base upon which this heady medicine has been brewed is a simple distortion circuit, so my first step is to pull the blend down to zero in order to check that out on its own. It’s bright but smooth, getting seriously gainy towards the top end of the dial and turning somewhat scuzzy near the bottom. Not surprisingly, this being a sensibleness-free zone, there are no clean options.

And so to the filter. Starting with a pure sine wave (curving up and down like a phaser), it’s instantly clear that its chewy swirl is a perfect match for the character of the distortion. The rate of the cycle can be set anywhere from several seconds to a rapid judder, while the peak knob and voice switch allow for fine-tuning of how dark it gets at the bottom of each swoop and how bright at the top. It’s bold and biting, but eminently likeable in a way that might make you decide for a brief moment that unfiltered guitar is dull and should be banned.

To the left of that on the mode dial, you’ll find a stepped wave that makes things just a little less smooth; then a random stepped wave (aka sample-and-hold) that takes us into the glitchy zone; and finally a random curve that basically arcs around at will like a broken auto-wah pedal.

And on the right? ‘Step down and ramp up’ is the least interesting option on offer, but it’s followed by an up/down square that’s great for aggressive tremolo-like effects; then a percussive down-ramping mode that brings in an element of sci-fi laser pew-pew; and finally up-ramping, which sounds properly scary at faster speeds.

Now, bear in mind that all of this is with the ring modulator locked away safely in a cabinet… but if you turn the bottom-left dial anywhere short of maximum, a whole new texture of fast-ripping weirdness is introduced. Flip up the far-left toggle switch and it gets even wilder, the stutteriness of the ring mod turning a strange sound into an entirely alien one. Top tip for scaring the neighbours: set the filter to a slow sine wave, hit a big chord and play with the ring knob as it decays.

Is the Vena Cava Filter easy to use?

Somehow, through all of these snowballing levels of extreme tone-chomping, the Vena Cava Filter remains musical at heart – yes, these are insane sounds, but I for one could conceivably find real-world uses for quite a few of them. An envelope-following mode would have been nice, and the ability to control the LFO speed with an expression pedal even nicer, but maybe those are ideas for a future Deluxe version. For now, this formula is more than potent enough.

Like this? Try these…

• Dreadbox Disorder £139
• Walrus Audio Kangra £170
• AC Noises Urla £229