ISP Technologies Theta Pro DSP

The ISP Technologies Theta Pro DSP is a floor-controlled guitar system: a programmable digital Theta preamp, a vintage-inspired preamp, studio-grade effects processing and a built-in precision tuner in one unit, with ISP's patented Decimator X noise reduction keeping high gain quiet¹². It runs on a DSP platform using a 32-bit floating point processor, and ISP describes it as a comprehensive system built for flexibility³⁴. It was designed and manufactured in the USA, and the product is patented³.

The unit carries dual preamplifiers, one distortion channel and one clean channel, each with the same control set: Gain, Bass, a swept midrange covering 300 Hz to 3 kHz, and Treble. The distortion channel adds switchable high-pass (300 Hz) and low-pass (3 kHz) filters for shaping where the gain sits².

What it does

The Theta Pro DSP combines the pieces most players otherwise spread across a pedalboard. The Theta preamp is fully programmable, and the second, vintage-inspired preamp gives a contrasting voice; both channels carry extensive pre- and post-equalization¹⁵. On top of the preamps sits a library of studio-quality 32-bit floating point digital effects, plus a full-function precision tuner¹⁵. For players comparing approaches, this is the same all-in-one territory as multi-effects pedals, but built around ISP's preamp circuits rather than amp modeling alone.

The noise reduction is a defining feature. ISP's Decimator X technology is patented, and the maker rates it at greater than 80 dB of noise reduction, aimed at quiet high gain performance¹². Players who know ISP from its standalone noise gate pedals will recognize the lineage.

Power and connections

Power comes from an external 9VAC supply; internally the unit generates +/- 15V power rails, which ISP says provide professional headroom and studio-quality equalization². This is not a standard 9V DC pedal supply, so it cannot share a typical DC daisy chain.

The rear panel is built for a full rig¹³:

• Inputs: 1 x 1/4" instrument, 1/8" external audio
• Outputs: 2 x 1/4" stage outputs, 2 x XLR direct outputs
• Control jacks: 3 x 1/4" for volume, expression and expression switch

The dual stereo outputs are a key part of the design: one stereo out drives a guitar rig, while the second carries ISP's speaker simulated output for direct recording or line out to the mixer³. That gives the unit a speaker simulation path for going straight to a desk or interface alongside a conventional amp feed.

Expression pedal control

An external expression pedal connects to its own quarter inch input, which the maker describes as map-able to countless parameters for on the fly control³. A separate volume pedal input and an expression switch jack round out the control connections¹.

Presets

ISP's current product page lists 224 presets organized into 124 songs, with 3 preset patches per song¹. The 2014 introduction press release stated 256 user programmable presets³. The Michael Sweet edition's page also lists 224 user programmable presets for sound library storage⁵.

Where it came from

Premier Guitar reported the Theta Pro DSP's introduction in December 2014, describing it as a new patented ISP Technologies product designed and manufactured in the USA³. The design work was credited to the original designers of the Intellifex, Chameleon, Voodoo Valve and Prophesy, the rack processors of an earlier era, working, in the release's words, "to make the Theta Pro the ultimate" guitar system³. The DSP platform's 32-bit floating point processing was said to allow "over the top gain unlike any other digital preamp without any background aliasing"³.

Allan Holdsworth endorsed the Theta Pro DSP in February 2017 after demoing it at a recent gig, ISP announced⁶.

The Michael Sweet Theta Pro DSP

In February 2017 ISP Technologies introduced a limited edition Michael Sweet Signature Theta Pro DSP, developed with the Stryper guitarist⁴. It has all the features of the standard Theta Pro DSP, with added software features, a Stryper-colored chassis and Michael Sweet presets⁴. Its product page describes the same core: a floor controlled guitar processing system with the THETA preamp and vintage preamp, Intelligent Speaker Simulation, and the studio quality 32-bit floating point effects library, plus inputs for both volume and expression pedals⁵.

The Theta Pro DSP is built in the USA, as ISP states on the product page: "Designed and manufactured in the USA."³ Its noise reduction is the digital version of the Decimator circuit, which ISP describes as "Digital Decimator X Technology / greater than 80db noise reduction"¹, and its early players included Allan Holdsworth, who ISP says endorsed the Theta Pro after demoing it at a recent gig⁶.

Videos

Click to load

Click to load

Click to load

Questions