ISP Technologies Hum Extractor + Decimator G

The ISP Technologies Hum Extractor + Decimator G is a two-channel noise reduction unit that tackles two different noise problems in one box. The Hum Extractor section, which ISP Technologies describes as patent pending, eliminates power line frequency hum, the low-frequency buzz that comes from ground loops, lighting dimmers and electrical wiring. The Decimator section handles broadband noise, the hiss and hash that high-gain amplifiers and distortion pedals add to a signal, with up to 80db of maximum noise reduction¹.

ISP Technologies positions it as a "two channel, ultimate noise reduction system"¹. For a player whose rig suffers from both hum and hiss, it addresses the two problems in a single unit rather than requiring a separate hum removal pedal and a separate noise gate.

Hum removal and noise reduction in one two-channel unit

The unit's two channels divide the work. The Hum Extractor channel targets power line frequency hum, the steady low-frequency tone that sits under a guitar signal and gets worse with single-coil pickups, long cable runs and poorly grounded stage power. ISP Technologies describes this section as patent pending, meaning the company has filed for legal protection on the specific method it uses to remove hum¹.

The Decimator channel is the noise reduction side. Where a conventional noise gate simply mutes the signal when you stop playing, the Decimator section is specified to deliver up to 80db of maximum noise reduction, pulling down the broadband hiss that high-gain preamps, distortion pedals and overdriven amplifiers generate¹.

For players comparing options, the two-channel approach is the distinguishing feature. A pedal such as the Electro-Harmonix Hum Debugger addresses hum alone, while a gate like the Boss NS-2 Noise Suppressor or ISP's own Decimator II G String addresses broadband noise alone. The Hum Extractor + Decimator G covers both jobs in one enclosure²¹³.

Levels, trim and matching the unit to a rig

The unit gives the player a way to set how hard the circuits are driven. It offers 21.5db of input level trim, with an input level range of -8dbu to +13.5dbu¹. In practice, input trim lets a player match the unit to the output level of the gear in front of it, whether that is a low-output vintage pickup or a hot line-level signal from a preamp, so the noise reduction circuits work from a known starting level rather than guessing at what is signal and what is noise.

The published specifications for the pedal and the rack version match on the core numbers: both are two-channel designs with up to 80db of maximum noise reduction, 21.5db of input level trim and the same input level range¹³.

Power and physical format

The Hum Extractor + Decimator G runs on 9V AC RMS at 1.5 amps¹. That is an AC power requirement, not the 9V DC center-negative supply most pedals use, and the 1.5 amp draw is far above what a standard pedalboard power brick offers on a typical 9V output.

Physically, the pedal measures 7.15 inches wide, 1.85 inches high and 4.5 inches deep, and weighs 1.2 lbs¹. At more than seven inches across, it takes up substantially more pedalboard real estate than a compact mini gate, so board space is worth considering alongside the power requirement.

The rack version

ISP Technologies also builds the design as the HUM EXTRACTOR + DECIMATOR G RACK, a rack unit that carries the same two-channel architecture and the same core specifications as the pedal, including the 80db of maximum noise reduction, the 21.5db of input level trim and the 9V AC power requirement³. Players who keep their effects off the floor, in a rack drawer or in a studio setup, can get the same hum extraction and noise reduction in that format. The rack unit has its own page covering it in detail: ISP Technologies Hum Extractor + Decimator G Rack.

Where it sits among ISP Technologies noise reduction products

ISP Technologies sells a family of noise reduction products, and the Hum Extractor + Decimator G is the one that combines hum removal with Decimator noise reduction in a single pedal, a design RockBoard's PedalPedia describes as patent pending². Its other Decimator pedals, such as the Decimator II G String, the Decimator II and the compact Deci-Mate, are listed alongside it in the company's range¹.

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