Holy Island Audio Super Freq

The Super Freq by Holy Island Audio is not for the subtle tone seeker, as it is wild and unruly — but in the most wonderful way!

Based on the discontinued Rattle Crow Restive Filter, the Super Freq is an input‑sensitive auto filter which is then blasted with a square‑wave fuzz. Think auto‑wah, but broken and angry. Holy Island Audio say the pedal will “fill a void in your sonic landscape you didn’t even realise was there”. This pedal will take your tone to another world, albeit in a dark and fractured universe.

The vibrant orange enclosure has end‑mounted audio jacks and a standard Boss‑style 9V DC power inlet. On the top panel, you will find seven knobs, an LED and a bypass footswitch. These pedals are all handmade in Cardiff, Wales with the enclosures even being screen printed in‑house. The finish is excellent, and the build quality matches that of any well‑known brand.

It’s best to think of this pedal in two parts: filter and fuzz. The filter section features two controls. Freq sets the frequency peak of the filtered signal, while Sens adjusts the filter’s sensitivity. Cranking the latter increases the interaction between the Filter and the Fuzz circuits. The Filter input is rather sensitive, so if you push the fuzz to an extreme, you’ll be greeted with a wild filter response. In fact, all the controls on the Super Freq interact to some extent, so their apparent behaviour largely depends on how the other controls are set.

On the Fuzz section, Holy Island Audio have supplied controls for several parameters, which means you can access a huge palette of sounds, with effects ranging from classic CMOS square‑wave fuzz right through to ‘screaming banshee’. The most recognisable control to fuzz‑heads will be the Starve knob, which adjusts the amount of power supplied to the Fuzz circuit. As you turn this back from the fully clockwise position you hear the Super Freq sputter and spit as it oscillates. The Strength knob acts as a gain control, giving you authority over the intensity of the fuzz. Structure is essentially a tone control, used to shape the character of the fuzz tone.

The player has so much control over the tone yet, at the same time, it also seems to have a mind of its own. I can’t sing its praises enough!

The Feed knob gives you control over the output of the Fuzz circuit, which feeds into the Filter section and, as you can imagine, this can deliver a variety of tones. Turning it all the way up unleashes a blanket of fuzz hell, whereas as dialling it back produces glitchy, lo‑fi noises, as the filter gets confused and struggles to know what to do. Finally, you have the Master output volume knob at the bottom of the pedal. It’s a fairly standard option but it’s particularly welcome on the Super Freq, given how loud it can become at some settings.

Once I’d read the detailed manual, I added the Super Freq to my pedalboard and plugged it into a Marshall JCM 900 amp. I set the Marshall to a light crunch, and once I activated the Super Freq I was in wild‑fuzz heaven. I found that by cranking the Feed control and dialling back the Starve knob I could then tune the filter with the Freq and Sens controls, creating a wild filter ‘jump’ sound with a lovely thick fuzz. I enjoyed this on monophonic riffs and lead lines, finding that it added a feeling of movement to the fuzz which I loved. Further testing with a Les Paul with P90 pickups led me to discover some vast fuzz tones, which were perfect for big chords or drones. Rolling the Filter controls back added a more subtle movement, without the glitchy breakup found in higher settings.

All in all, I’m a big fan of this pedal. It’s aggressive and wild in all the right places, and it brings to mind the behaviour of the Schumann PLL. The player has so much control over the tone yet, at the same time, it also seems to have a mind of its own. I can’t sing its praises enough!