The HBL-4 is the latest incarnation of the Heat Blaster, an ultra-dynamic distortion from the Japanese Providence line. It’s a fine option for players seeking crunch tones with sufficient edge to slice through a band.
While the HBL-4 employs a standard 9V battery or power supply, the circuit includes a voltage doubler that runs the effect at 18 volts. The resulting headroom keeps the high end crackling while preserving note attack. There are the usual gain, level, and volume controls, but their ranges and tapers are uncommonly musical. Low-gain/high-level settings growl. High-gain/low-level settings are fat. Cool in-between settings are legion. And when you roll back the guitar volume, tones clean up in ways no Screamer or Rat can equal.
There are usable sounds throughout the entire tone knob range. There’s also a bass-cut switch (labeled “bass boost,” but whatever) that excels at bright Bluesbreakers-style leads. And as any savvy low-tuned/7-string rocker will tell you, cutting lows can make the bottom register speak. Just one caveat: Between the bass cut and the bonus headroom, highs can run rampant. You can definitely rein them in, but it may take a moment.
Test gear: Les Paul Custom with unpotted PAFs, Carr Lincoln amp.