ISP Technologies Empyrean

The ISP Technologies Empyrean is a preamp pedal built around two separate preamplifiers, a Distortion channel and a Clean channel, with the company's Decimator X noise reduction built in. It was developed through a collaboration between ISP Technologies and Michael Sweet of Stryper, and ISP unveiled it on 31 May 2024¹. On the pedalboard it can stand in for an amp's front end, giving you a dirty and a clean voice, each with its own set of tone controls, in one box. It sits in the wider family of preamp pedals.

Two preamps, one pedal

The Empyrean carries two independent preamps. ISP's product page describes the pedal as bringing "Michael's new tone machine with dual preamplifiers"², and the press release spells out the split: "Dual preamplifiers: Distortion and Clean channels"¹. ISP frames the two voices in the language of the music Sweet is known for, saying the pedal covers "the raw, gritty distortion or the sparkling clean tones that defined the 80s rock scene"¹.

Each channel has its own control set, so the two voices can be dialed in separately²¹:

The semi-parametric Swept Midrange is the control worth spending time on: rather than a fixed mid band, it lets you choose where in the 300Hz to 3KHz range the mid control acts, which is how players typically dial out boxiness or pull forward a solo voice. ISP says the pedal provides "true professional headroom allowing you the use the full capabilities of the Pro Studio quality equalization"².

The Distortion channel also has a switchable high pass filter at 300Hz, which ISP describes as a way "to tighten up that bottom end"², a common need in high-gain and dropped-tuning playing where low-string flab can crowd the sound.

Stacking the channels for more gain

Beyond running the two channels as separate voices, the Empyrean lets one drive the other. ISP explains that "for those who want even more gain you can switch on the Clean Channel to over-drive the Distortion channel," giving what the company states as "more than 160db of distortion gain"². In practice that turns the pedal into a two-stage gain machine: the clean preamp pushes the distortion preamp the way a boost or overdrive would push an amp's input, for players who find the Distortion channel alone not enough.

Noise reduction on board

High-gain preamps are noisy, and ISP has addressed that directly. On board is what the company calls "the newest generation, patented, Decimator X, Noise reduction technology, G String version which tracks the direct Guitar input"². The G String approach follows the guitar's signal directly rather than only the processed signal, which is ISP's method for keeping noise down without clamping the ends of notes as hard as a simple gate can. For players comparing options, ISP's Decimator designs also exist as standalone units, and the broader category is covered on the noise gate pedals page.

Volume boost for solos

Michael Sweet also specified a solo tool: "foot switchable and adjustable Volume Boost for that extra volume needed for solos"². The press release lists it as a "Footswitch for instant volume boost"¹. The boost level is adjustable, so the jump in volume can be set to taste rather than fixed.

Power

The Empyrean runs on an external 9VAC power supply, which ISP says is "internally multiplied to provide +/- 15 volt power supply rails"². The higher internal rails are what the maker points to for the pedal's headroom, but the AC supply is the practical detail to note before adding it to a board.

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