ISP Technologies ISP Decimator II G-String

The ISP Decimator II G-String is a guitar noise reduction pedal from ISP Technologies, the second generation of the company's Decimator G String design. What sets it apart from a simple noise gate is its dual-jack layout: it reads the signal straight from your guitar through its own instrument input, and it can gate at a second point in your rig through a loop send and return. That means the noise reduction tracks what your hands are doing, not just the noise sitting at one spot in the chain¹².

The pedal was released in June 2013 alongside the plain Decimator II, as an updated version of the earlier Decimator G String pedal. Both new pedals added link connections and improved expander tracking over the originals³⁴.

What it does, and how it differs from the Decimator II

The Decimator II G-String is part of ISP's Decimator line of noise reduction gear, which spans pedals, micro pedals and 1U rack units. The core of the line is expander-based noise reduction: instead of a hard gate that snaps shut, the circuit tracks the signal and reduces it as the level falls. The Decimator II generation uses what ISP calls linearized Time Vector Processing in its expander tracking, which the maker describes as giving smooth sustained-note decay virtually free of release rippling⁸. Premier Guitar's review of the original G String pedal put the same idea in plainer terms:

The difference between the two second-generation pedals is the routing. The Decimator II is a single-point gate: one 1/4" input, one 1/4" output, placed wherever you want noise cut in your chain⁸. The G-String version adds the second signal path. Guitar World's noise gate buying guide describes the G String as a version of the Decimator that offers send and return connections, at a somewhat higher price⁹. The payoff is that the pedal can compare the clean guitar signal with what comes back through the loop, and remove noise based on that comparison.

The same tracking-the-guitar approach runs through the wider family. ISP says of its DECI-MATE G Micro Decimator that because the noise reduction directly tracks the guitar output, the threshold needs no adjustment when switching between gain settings². The later Decimator G String X carries the idea further with patented adaptive noise reduction technology, under US Patent 11,641,183⁷.

The Threshold knob and the jacks

The control set is minimal. The G String design consists of one threshold knob and an active/bypass switch, as Premier Guitar described in its roundup review of the original pedal¹. There is no release-time control, no decay knob and no sidechain filter: the Time Vector Processing is meant to handle note decay on its own, so the single knob is the whole user interface.

Setting it up is a two-step process:

1. Run your guitar into the instrument input and out of the main output, and connect the loop send and return to the point in your rig where you want the second stage of noise reduction.
2. Set the threshold knob until the noise is eliminated to taste⁶.

The four 1/4" jacks each have a distinct job⁵:

• Instrument in: your guitar plugs here, and the pedal reads this signal directly to drive its tracking.
• Main out: feeds the next thing in your chain, typically the amp's front input.
• Loop send and loop return: connect to your amp's effects loop send and return, or to another point in the chain, so the pedal can gate there too.

Gearnews's noise gate guide describes this two-place arrangement in the context of the later Decimator X G-String: it gates in two places at once, in front of the amp and inside the effects loop, keyed off the same detection¹⁰. The same principle applies to the II G-String's jack layout.

Linking two pedals

The two 1/8" jacks are the link in and link out. ISP Technologies makes both the Decimator II and the Decimator G String II, and the G String II is a noise reduction pedal³⁴. The second-generation pedals were announced in 2013 as updated versions of the earlier Decimator II and Decimator G String pedals⁴. How the linking function behaves in practice is best checked against ISP's own documentation for the specific pedals you own.

Where it came from

The Decimator II and Decimator G String II come from ISP Technologies³. The G String II is a noise reduction pedal, released as a brand new updated version of both the earlier ISP Technologies Decimator II and Decimator G String pedals⁴. Reviewers took to the high gain noise reduction: the Decimator II G-String was described as "a dream come true for metal players who love high gain but hate the noise"⁶.

What reviewers said

Pedal of the Day reviewed the Decimator II G-String in June 2016 and was positive about it. The reviewer found it "a fantastic way to clean up your signal without sacrificing your tone or your ability to change between channels and settings on your amp," and called it "a dream come true for all of the metal players out there who love high gain but hate the noise"⁶. On the tone question, the same review said the pedal uses the comparison between the guitar signal and the loop signal to remove noise "without killing your sound or your dynamics"⁶. The review also lists Josh Elmore among the pedal's users⁶.

That verdict lines up with what Premier Guitar said about the G String line more generally, describing the Decimator G String Noise Reduction pedal as "a welcomed addition to any noisy guitar rig"¹¹.

Videos

Click to load

Click to load

Click to load

Questions