Whether you’re a high-profile artist or a guitar hobbyist, there’s a good chance you’ve had reason to pay attention to the work of Alex Aguilar. From his time building bass amps at Aguilar Amplification to his work as a guitar columnist, Aguilar has been chasing great tone for more than 40 years.

His newest company, Alairex, is thus far a fairly small outfit, with the H.A.L.O. overdrive reviewed here being the company’s first and only product so far. But what the Alairex line may lack in quantity, it makes up for in terms of thoughtful design and engineering, because the H.A.L.O. is hardly another run-of-the-mill overdrive. Aguilar designed the H.A.L.O. to get natural amp overdrive but with more touch sensitivity and response than you typically get from a stompbox. Impressively, the unit achieves many of those aims, giving you tone-crafting power that you don’t often get from an overdrive.

Heaven Sent
The robust little H.A.L.O. weighs in at almost 1 1/2 pounds, and you’ll definitely notice how sturdy and stage ready it feels. But you’re more likely to be struck by the myriad ways you can tweak its tones. The all-analog circuit controls two footswitchable gain modes, each with its own dedicated gain and master volume controls. Three smaller knobs at the top edge let you boost or cut sub frequencies, midrange response, and upper mids. There’s also a master tone control that sweeps through a range of voicings from super bright to dark and mellow. You can also power the pedal with an 18V power supply to increase headroom if the tone is too congested for your liking.

The pedal’s 3-way shape toggle enables you to switch between two diode-clipping modes or a clean boost mode in the middle position. Most analog overdrives use either symmetrical (Ibanez Tube Screamerstyle) or asymmetrical (Boss SD-1 Super Overdrive-style) diode clipping, but the H.A.L.O. attempts to give you the best of both worlds by opening up access to the smooth, natural response of even-order harmonic distortion that’s a hallmark of power-tube overdrive, or the more fluid and compressed odd-order harmonic distortion that’s common in gained-out preamp overdrive. Its 3-way saturation toggle adds the option of piling even more distortion and compression on both gain modes, or on the second gain mode exclusively.

Tone Evolution
The H.A.L.O.’s control layout looks daunting at first, but it’s actually very intuitive and responsive once you’ve done a little homework.. There are a lot of different tones on tap, and really the only hurdle you’ll face is deciding which of the many flavors works best.

With a Vox AC30 and a Stratocaster, I set the H.A.L.O. for asymmetrical clipping and the gain and tone-shaping controls at noon. Even at these relatively conservative levels, there was a very obvious jump in volume. Turn the asymmetrical mode’s gain control up to about 1 o’clock, and you get even more volume, in addition to a thicker midrange and more robust low end—perfect for Zeppelin riffs and crunchy ’70s-rock staples. It’s not unusual for a good overdrive to send an AC30 to Page-ian heights, but with the H.A.L.O., you also notice how much detail remains intact within the snarl and grind. And the bass, contour, and presence knobs are all very effective for fine-tuning the distortion and tailoring output to your guitar and amplifier.

At extreme levels, the gain control will drive most amps into Van Halen-heavy raunch that works as well for clear chords as legato leads. But you can also use your guitar’s volume to take advantage of the pedal’s exceptional sensitivity—it cleans up without obscuring picking dynamics.

Alairex doesn’t bill the H.A.L.O. as a pedal for metal guitarists, but it works beautifully for heavy rock in the second gain mode, especially when you put highoutput humbuckers at the front of the signal chain. You’ll hear a lot of aggressive mids, though the bass can lose some of its stand-and-deliver tightness under barrages of staccato picking or palm-muted triplets. Backing off of the bass control brings back some low-end foundation and a little more softness in the bass attack, illustrating just how vital the tone controls are to getting the most out of the H.A.L.O.

Engaging the saturation switch makes the second gain mode monstrous—capable of grind that would turn the head of any metal fanatic, as well as a broad range of high-gain colors that you can transform subtly or radically with your guitar’s volume knob. You’ll also hear and feel a little sag at this point, which is great for lower-gain rhythm tones. Paired with the AC30, this mode yielded a voice reminiscent of a 50-watt Marshall JCM800.

The Verdict
Alairex’s Alex Aguilar is a tone-shaping veteran, and his new H.A.L.O. lives up to the lofty expectations that come with a resume like his. It’s a multifaceted overdrive machine capable of everything from velvety drive to raging distortion. But what’s even cooler is the extent to which the H.A.L.O. enables you to do much of that work yourself with pick attack and your guitar’s controls. This is the rare pedal that can move between a strong personality and a natural, near transparency, depending on how you set it up. And that makes it one of the most musical overdrives you’ll find anywhere.