2hp Attenuator (2010s)
Two channels of passive signal taming in the smallest footprint you can plug into a Eurorack case
Overview
Patch in a modulation source and the sound can spiral into screeching feedback. An external synth's output can slam a mixer into clipping before the knob is even touched. The 2hp Attenuator sits in the trenches for exactly this. It doesn't generate sound, it doesn't filter, it doesn't make envelopes - it just turns things down. In a modular system, where voltage levels are wild and unforgiving, that is essential.
This isn't a fancy VCA with CV control or exponential curves. It's two independent, passive attenuators, each with a single knob that rolls off signal from unity gain all the way to silence. There's no power draw and no circuitry to fail - just resistors and potentiometers. It fits in 2HP, so you can tuck it next to a noisy oscillator, a hot LFO, or a runaway envelope without giving up much panel space. In a format where every millimeter counts, that matters.
It has quirks. Being passive, it can't boost signals, only reduce them. If you're trying to amplify a weak CV or bring up a quiet audio line, you're out of luck. It also doesn't buffer, so long cable runs after attenuation might still pick up noise. But that's not what it's for. It's for precision trimming, for dialing in the right amount of modulation depth, for making sure your sequencer's gate output doesn't overdrive your vintage-style synth module. Think of it as the trim knob on a DAW channel - invisible when working right.
Specifications
| Manufacturer | 2hp |
| Production Years | 2010s |
| Format | Eurorack |
| Width | 2HP |
| Depth | 27mm |
| Power Requirements | None (passive) |
| Channels | 2 |
| Function | Passive attenuation |
| Attenuation Range | 0% to 100% (unity to silence) |
| Signal Type | Audio and CV |
| Input Impedance | High (passive design) |
| Output Impedance | Depends on potentiometer position |
| Knobs | 2x rotary attenuators |
| Panel Color | Black |
| Mounting | Standard Eurorack screw holes |
| Weight | Approx. 20g |
Key Features
Passive by Design, Not by Compromise
The 2hp Attenuator is passive because it doesn't need to do more. There's no op-amp, no power rails, no risk of noise injection from a poorly regulated supply. It's just a potentiometer per channel, wired as a voltage divider. That means it loads the source slightly, but in most Eurorack contexts that's negligible. What it gains is reliability: no power, no failure points. It should work just as well in 2040 as it does today, assuming the pots don't get dusty. And because it draws no current, it costs nothing on your power cable.
Skiff-Friendly Signal Control
At 2HP wide, this module is barely wider than a single Eurorack mounting screw. In a skiff or a travel case where space is at a premium, you can dedicate one to each critical signal path: one for your external audio input, one for a modulation source feeding a filter cutoff, another for a clock divider's gate output. It's the kind of module you buy in multiples. Some users even mount them directly next to modules that lack input attenuators.
Audio and CV Agnostic
It doesn't care what kind of signal you throw at it. A 10V LFO? Fine. A 5V gate? No problem. A hot 20kHz oscillator output? It'll roll it back without coloration. Because it's passive and linear, it treats control voltages and audio signals the same way - no frequency-dependent roll-off, no phase shift, no added distortion. What you put in is what you get out, just quieter. It won't sweeten your sound or add grit.
Historical Context
The 2hp Attenuator arrived in the early 2010s, as Eurorack was shifting from boutique curiosity to mainstream modular format. Back then, many modules, especially from smaller builders, lacked input attenuators. You'd patch in an LFO and your filter would self-oscillate at maximum resonance because the modulation depth was full-on. The market responded with utility modules, and 2hp, known for minimalist design and extreme space efficiency, leaned in hard. The Attenuator wasn't the first attenuator, but it was among the first to deliver two channels in 2HP.
At the time, other companies were packing more features into wider modules - VCAs with CV, attenuverters, offset controls. 2hp went the opposite direction: strip it down, shrink it, make it ubiquitous. As systems grew more complex, the need for signal management grew with them. The Attenuator, along with modules like the 2hp Trim (a nearly identical sibling, likely the same module under a different name), became a workhorse in thousands of racks.
Collectibility & Value
This isn’t a module that appreciates. It’s not rare, it’s not discontinued, and it’s not particularly sought after as a collector’s item. But that’s not a knock—it’s a sign of success. The 2hp Attenuator is so useful and so well-priced that it’s considered a staple, like patch cables or power distribution. You don’t collect it; you use it. That said, condition matters. Original units with clean, smooth-turning pots are common, but older units might suffer from scratchy knobs or intermittent output if the potentiometers have degraded. Cleaning with contact cleaner often fixes this, but if the pot is worn out, replacement is straightforward for anyone comfortable with soldering.
On the used market, expect to pay between $25 and $40 depending on condition and whether it's sold as part of a bundle. New units, if available from dealers, might list for $50 - $60, but they're often sold out or available only through secondary markets. Because it's passive and simple, there's no firmware, no calibration, no alignment. That makes it a good first module for beginners, and many skiff builders include one or two as standard equipment. There's no counterfeit market and no "vintage vs. reissue" debate.
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