The Blackbox Cobalt ($225) is a clean boost and overdrive pedal designed for use with guitar and bass. Like all Blackbox pedals, the Cobalt is assembled, soldered, and painted by hand. Optimum audio performance is achieved by using only the highest quality components, and three coats of baked enamel ensure that the Cobalt looks as good as it sounds.

The Cobalt has a very high impedance input to reduce pickup loading and is designed to interact well with the widest variety of guitar and bass electronics. True bypass switching removes all circuitry from the signal path when the pedal is not engaged.

GAIN THEORY

The unit has four knobs and a heavy-duty footswitch but no LED status indicator — Blackbox feels that LEDs consume too much battery power, which is important, as the Cobalt has no external power jack. Three of the pedal's knobs control individual stages of gain, and the useful Bias knob adjusts the signal bias, affecting compression, waveform symmetry, and other crunch factors. The Gain control adjusts the input gain level and can be used to pad hot input signals or to drive the two subsequent gain stages into a tube-amp-like overdrive (even at unity gain). The Drive knob controls the second gain stage, which also pushes the pedal into overdrive. Overall output volume is adjusted with the Volume knob.

This arrangement may appear quite simple, but all of the controls are highly interactive and significantly affect the operation of the others, meaning that while it is possible to get a good clean or overdrive sound fairly quickly, a wide variety of distinct sounds can be created if you are willing to invest time in experimentation.

BOOST AND BLAST

Most of my testing was done using a PRS Custom 24 guitar and a Rivera Thirty Twelve amp, but I tried the pedal with an old Les Paul Custom and a stock American Strat as well. Besides connecting the pedal in-line between the guitar and amp, I also patched it in to the Rivera's effects loop with excellent results. The very high impedance input and ample headroom on the output probably explain why it worked so well in the loop. Patched in to the loop, the pedal came after the input preamp in the signal chain and functioned best at unity gain.

With the gain structured correctly, I generated a ton of extremely clean boost with negligible signal breakup. Not only was the signal loud and clear, but the sound of each instrument was enhanced without losing any of its essential character. Increasing the pedal's output volume pushed my amp's input just enough to break up the sound in a pleasant way, and slightly increasing the Drive and Gain added just a bit of crunchiness to the blend.

The Cobalt's overdrive is rich, smooth, and throaty — though a far cry from “distortion,” so don't expect ultrasaturated shred tones. That said, if you crank up the Drive and Bias controls and push an already distorting amp, the Cobalt adds tons of creamy sustain and harmonic sparkle — particularly on instruments with humbuckers. Blues, country, and most pop and rock players should be able to find lots of great sounds to work with.

The Cobalt is pricey, but considering the construction and sound quality, it's still a good value — particularly compared with the one or two clean boost pedals that might be considered its competition. If you want a pedal that delivers lots of headroom and sophisticated overdrive without changing your instrument's basic tone, check this pedal out.

Rating (out of 5): 4.5

Blackbox Music Electronics; tel. (612) 623-7957; e-mail blackbox@blackboxmusicfx.com; Web www.blackboxmusicfx.com