Save for its singular single-knob control panel in bright red finish, a quick glance at the new Vox AC30 Brian May Custom Limited Edition amplifier reveals little if anything that separates it from the typical AC30. With its familiar brown-diamond grillecloth, black tolex, white and gold piping, trio of carrying handles, and full-radius plastic corners, it does indeed look like plenty of other Vox amps.

But look closer (then plug it in) and you’ll see there are many things that help the AC30BM Custom stand out…

An amp set for limited production (500 units, 200 bound for the U.S.), the AC30BM control panel plays host to May’s autograph in white silkscreen, a Power switch, Standby switch, Volume control, and… well that’s it. There are no for controls for tone, presence, or gain, no jacks… just volume. It seems that for this amp, Vox and Brian May did all the tweaking for us, and while the implied lack of control may throw some players into shock, it can also be liberating to simply plug in, flip a switch, and start playing without having to “find your sound” by noodling with knobs.

In reality, there are ways to adjust the AC30BM. The back panel has a micro slide switch for boosting gain in the preamp. This circuit compensates for differences in pickup output and approximates the effect of a custom-made treble/mid-boost pedal May traditionally used in his signal chain. There’s another switch for adjusting the amp’s output mode to 15 or 30 watts, and a Treble Boost switch that engages the renowned Vox treble/top-boost sound.

Vox’s approach to the 15-/30-watt circuit is a bit different than most others in that it not only takes two EL84 power tubes out of the circuit and changes the value of the output-cathode resistors that bias the output tubes, but it also changes the impedance of the output transformer (which then gives true half-power with full-power performance). Pretty trick.

The cabinet is made of Baltic birch plywood with a steel/aluminum chassis and a combination of point-to-point wiring with printed circuit boards (for the boost circuit only). Our test amp used a pair of 12″ Celestion Alnico Blue speakers.

To have a listen to the AC30BM, we plugged in a G&L Will Ray ASAT, a Gibson Les Paul Studio with stock humbuckers, and a Hamer Daytona with single-coils. With the amp’s boost switch off, the single-coils in the Hamer and the Z-coils in the ASAT produced a full, fat tone with plenty of chime to the highs and big, round 2×12″ low-end. The more we pushed the amp’s Volume control, the more bark and drive it delivered. Not over the top, but teetering on the edge of distortion. And it cleaned right up when we rolled off the guitar’s volume control, never surrendering any of what makes the tone from this amp so cool.

Kicking in the boost circuit opened a whole new world of tone, with huge mids, tighter low-end response, and plenty of that sweet Vox overdrive that makes single notes and chords alike pop. Midrange response was very present, even a bit in-your-face, but not nasally, while the treble boost made the highs sizzle with a crisp, singing quality. Backing down the guitar’s Volume again cleaned up the sound for a less-aggressive rhythm tone that stayed crunchy.

The humbuckers in the Les Paul proved a little dark with the treble boost off, but very at home with it engaged, producing a full, thick overdrive with the Gain switch on the low setting and an aggressive, raunchy distortion that was still clear and dynamic on the higher gain setting.

When you consider that this amp has just one knob, with the help of the three backside slide switches and the controls on the guitar, it produces an amazing variety of good, usable sounds, each with their own character. And yes, its bold, clear treble boost nails Brian May’s tone so convincingly it could only be more authentic if May himself showed up with his homemade Red Special. Plus, the amp’s dynamic range and half-power capability (which works without sacrificing one iota of tone) give it huge potential, even for smaller-venue gigs or studio work.

So, though it (eh hem) may lack a bunch of knobs, the AC30BM certainly does not lack tone. A good axe and setting a couple switches will instantly help any player make killer British tones.

Vox AC30 Brian May Custom Limited Edition
Price $3,000 (retail).
Contact Korg U.S.A.,316 South Service Road, Melville, NY 11747; www.korgusa.com.

This article originally appeared in VG‘s JulY ’06 issue. All copyrights are by the author and Vintage Guitar magazine. Unauthorized replication or use is strictly prohibited.