2HP Zlob (2016–2018)

A sliver of analog chaos that fits in the cracks between your other modules—noise, random voltages, and sample-and-hold in a 2HP coffin.

Overview

You know that moment when you're patching and realize you're one tiny module away from total mayhem? That's where the 2HP Zlob lives—not as a centerpiece, but as the spark in the dark corners of your rack. It doesn’t sing melodies or hold chords, but it breathes unpredictability into rigid sequences, turning a robotic arpeggio into something alive, twitching, almost nervous. The Zlob is a sample-and-hold module with a built-in noise source, and it’s about as compact as analog circuitry can get without vanishing entirely. At just 2HP wide, it’s the kind of module you install because you ran out of space but still needed one more source of controlled randomness. And somehow, it delivers.

Originally designed by Onur Kalaycıoğlu under the Złob Modular name (later acquired and rebranded by 2HP), the Zlob was never meant to be a flagship. It was a solution—a way to squeeze entropy into a format where every millimeter counts. It made its debut around 2016, a time when Eurorack was exploding in popularity and skiff-builders were fighting over every half-inch of panel space. The Zlob answered that fight with a scalpel: minimal footprint, maximum utility. It didn’t try to do everything—just one thing, and do it well.

Sonically, it’s raw. The noise generator produces white, pink, and brown (also called red) noise, all analog, all slightly gritty in that way only discrete circuits can be. It’s not pristine like a digital noise source; it crackles with character, like an old AM radio tuned between stations. That noise feeds directly into the sample-and-hold circuit, which can be clocked externally or left to free-run. The output is a stepped random voltage, perfect for modulating pitch, filter cutoff, or pulse width. There’s a trimmer on the PCB to adjust the gain of the white noise, which in turn affects the voltage spread of the S&H output—tweak it, and you can go from subtle wobble to full-on stochastic madness.

What’s striking is how much function they packed into such a narrow space. The panel is laser-cut acrylic, available in multiple colors, and while it looks delicate, it holds up fine if treated with basic care. The module draws 15mA from both the +12V and -12V rails, with no 5V requirement—standard for its era. It was sold both as a DIY kit and pre-assembled, appealing to builders and plug-and-play users alike. But be warned: early versions had components that slightly overhung into the third HP, meaning tight module spacing could cause mechanical interference. Some users solved this by mounting it with a 3HP panel instead, though the original 2HP version still fits if you leave a little breathing room.

Specifications

Key Features

Analog Noise with Character

The Zlob’s noise generator isn’t just a utility—it’s a tone generator in disguise. White noise here isn’t flat and clinical; it’s slightly colored, with a warm top end and a low-end thump that feels more organic than most discrete designs. Switch to pink or brown noise, and you get progressively darker textures—brown noise especially has a rumbling, almost subsonic quality that’s perfect for modulating slow-moving parameters or creating atmospheric pads. Because the noise is analog and unfiltered by design, it retains harmonic complexity that digital noise sources often lack. It’s not just "random"—it’s *musical* random, the kind that feels like it belongs in a patch rather than just filling space.

Sample-and-Hold with Normalled Chaos

The sample-and-hold circuit is where the Zlob earns its name (Polish for "rage" or "tantrum"). It’s simple: clock it, and it grabs a voltage from the internal noise source and holds it until the next clock pulse. But the brilliance is in the normalled connection—plug nothing into the S&H input, and it automatically uses the internal noise. That means you can drop this module into a patch and immediately start modulating things without a single extra cable. Want to randomize your VCO pitch? Patch the S&H output to a 1V/oct input. Want to make your filter squirm? Route it to the cutoff. The voltage range is adjustable via a PCB trimmer, letting you dial in anything from micro-modulations to full-scale jumps across octaves.

Smooth Random CV: The Hidden Gem

Tucked away is a lesser-known but deeply useful output: smooth random CV. Unlike the stepped output of the S&H, this is a slow-drifting analog voltage between 0–5V, generated via an infrared-based smoothing circuit. It’s perfect for creating evolving textures—slowly shifting drone tunings, gradual brightness changes, or ambient morphing. The offset is adjustable via another PCB trimmer, so you can bias the range higher or lower depending on your needs. It’s not a feature you’ll use every day, but when you need it, you’ll wonder how you lived without it.

Historical Context

The mid-2010s were a golden age for Eurorack minimalism. Skiff culture was in full swing, and builders were obsessed with squeezing maximum functionality into minimum space. The 2HP Zlob arrived right in the middle of that movement—not as a trendsetter, but as a perfect embodiment of it. It wasn’t the first 2HP module, but it was one of the first to prove that such a narrow format could still deliver serious analog performance. Competitors like Intellijel and Doepfer were focusing on larger, more feature-rich modules, while boutique builders like Złob (and later 2HP) carved out a niche for ultra-compact utilities.

It also reflected a broader shift in modular philosophy: the idea that randomness and unpredictability were not flaws, but features. In an era where digital synths could produce perfectly quantized sequences, the Zlob offered the opposite—a module that embraced analog drift, noise, and imperfection. It stood alongside other chaos-bringers like the Mutable Instruments Marbles or the Make Noise Wogglebug, but with a fraction of the footprint and cost. For a generation of modular users building their first skiffs, the Zlob was an affordable, no-frills way to inject life into rigid patches.

The acquisition by 2HP in the late 2010s cemented its legacy. 2HP, already known for minimalist designs like the VCA and SINE, was a natural home for the Zlob. But production was short-lived—the module was discontinued by 2018, likely due to low margins and the niche appeal of such a specialized utility. Still, its influence lingered. It proved that even in 2HP, you could fit a fully functional analog noise and S&H circuit, paving the way for future ultra-compact modules from brands like ALM and Noise Engineering.

Collectibility & Value

Today, the 2HP Zlob is a sought-after oddity—a module that’s more about charm and utility than raw power. It won’t command the prices of rare VCOs or filters, but it’s not common, either. On the used market, expect to pay between $100 and $140, depending on condition and whether it’s the original Złob-branded version or the later 2HP release. Original DIY kits in good working order tend to be on the lower end, while pre-assembled units with clean panels can fetch closer to $140, especially if they come with rarer panel colors like black or translucent red.

Condition matters. Because the module uses surface-mount components and a double-sided PCB, repairs can be tricky. The most common failure points are the power pins and input jacks, which can develop cold solder joints over time. Users have reported occasional ground loop noise when used with certain USB-controlled gear (like the Expressive E Touché), though this is usually resolved with proper cabling or isolation. The laser-cut acrylic panel is durable but can crack if overtightened or dropped—replacements are no longer available, so original panels in good condition add value.

For buyers, the biggest red flag is functionality. Test the S&H output with a clock source: the voltage steps should be clean and stable, with no stuck values or drift. The noise output should be consistent across all types, with no hum or oscillation. If the module was built from a kit, check for proper soldering—some early build docs had incorrect capacitor values, leading to instability if not corrected. And remember: while it’s labeled 2HP, the PCB slightly overhangs into the third HP, so verify spacing in your case before buying.

Restoration is possible but not trivial. The lack of publicly available schematics (Złob never released them officially) means troubleshooting requires reverse-engineering or community-shared diagrams. Recapping is rarely needed unless the module has been stored poorly, but cleaning the jacks and checking power connections is wise for any used unit. Given its low current draw and simple circuit, it’s not a fire hazard—just a finicky little beast that demands respect.

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