2hp Mixer (2008–2020)

Name: 2hp Mixer
Brand: 2hp

Four channels, one output, and a faceplate so tiny it disappears—this is mixing stripped to its bones.

Overview

You don’t so much install the 2hp Mixer as you forget it’s there—until you need it. At just 2HP wide, it’s one of the narrowest functional modules in Eurorack, a sliver of brushed aluminum that fits where others wouldn’t dare. Plug in four audio or CV signals, dial in their levels with the four tidy knobs, and send the sum to a single output. That’s it. No panning, no mute buttons, no trim pots or polarity switches. There’s no power-sucking op-amp circus under the hood, no digital brain—just passive summing with minimal buffering. What you get is transparency with a slight analog warmth, the kind that doesn’t color your sound so much as let it breathe together.

Despite its size, it’s not a toy. The Mixer handles both audio and control voltage with equal competence, making it useful for summing oscillators, blending modulation sources, or collapsing a stereo field down to mono before hitting a filter or effects chain. It’s the module you reach for when you realize you’ve run out of mix bus real estate but still need to glue a few elements together. And because it’s 2hp, you can fit two or three of them in the space most modules take up alone. That kind of density is rare, even in the crowded Eurorack ecosystem.

It’s not the loudest mixer out there—don’t expect pro-level headroom—but within a modular context, it performs cleanly up to line level. There’s no clipping circuitry, so hot signals will distort, but in a soft, musical way that some users actually exploit for saturation. For quiet, clean summing, it’s excellent. For aggressive blending, it’s forgiving. And because it’s passive-first, it loads the output of whatever feeds it slightly, which can subtly round off sharp transients—sometimes a feature, sometimes a quirk, depending on your patch.

Specifications

Manufacturer	2hp
Production Years	2008–2020
Original Price	$99 USD
Module Width	2HP
Power Requirements	±12V, 20mA total
Inputs	4x 3.5mm jacks (audio or CV)
Output	1x 3.5mm jack
Input Impedance	100kΩ
Output Impedance	1kΩ
Frequency Response	20Hz – 20kHz (-1dB)
THD	<0.1% at +4dBu
Max Input Level	+10dBu (before soft clipping)
Weight	35g
Depth	35mm
Panel Material	Aluminum, black anodized
Knobs	Black plastic, pointer tip

Key Features

Minimalist Summing Architecture

The 2hp Mixer uses a passive resistor network for summing, followed by a single buffered output stage. This design keeps noise low and power draw minimal while avoiding the phase shifts and crosstalk that can plague poorly designed active mixers. The resistors are precision 1% tolerance, ensuring balanced channel contribution. Because it’s passive at the front end, the module presents a consistent load to upstream modules, which can slightly affect the behavior of certain oscillators or filters—especially those with high output impedance. Most users won’t notice, but in sensitive patches, it can be a subtle tonal tweak.

Compact Form Factor

At 2HP, this module is a space-saving marvel. It’s narrower than a single banana jack on many cases. This makes it ideal for skiff builds, travel systems, or any setup where every millimeter counts. You can fit a stereo mixer (two units) in 4HP, or a 6-channel bus with three units in just 6HP—something nearly impossible with standard 8–10HP mixers. The compact size does mean the knobs are close together, so if you have large fingers or use thick cables, you might find patching a bit fiddly. But for the trade-off in density, most users accept the tight quarters.

Audio and CV Versatility

While marketed as an audio mixer, the 2hp Mixer handles control voltage with equal ease. Summing LFOs, envelopes, or sequencer outputs is common in modular synthesis, and this module does it transparently. Because it’s DC-coupled, there’s no low-frequency rolloff, so slow CV signals pass through unchanged. This makes it useful as a mathematical module—adding offsets, averaging modulation sources, or creating complex control voltages from simple ones. It’s not a quantizer or logic processor, but in a pinch, it can perform basic analog computation.

Historical Context

The 2hp Mixer arrived in 2008, right as Eurorack was shifting from boutique curiosity to mainstream modular format. At the time, most mixers were 8HP or wider, often with features like panning, level meters, or multiple outputs. 2hp—the company—bet that a growing number of users valued density over features. They were right. The Mixer became a staple, not because it did more, but because it did less in less space. It appealed to minimalists, skiff builders, and those tired of sacrificing oscillator or filter space for basic summing.

It wasn’t the first small mixer, but it was the first to gain widespread adoption at 2HP width. Competitors like Intellijel and Doepfer offered mixers, but they were broader and often included extras like mute switches or polarity inversion. 2hp stripped all that away, betting on utility through minimalism. In an era where modules were getting bigger and more complex, the Mixer was a quiet rebellion—a reminder that sometimes, a knob and a jack are all you need.

Collectibility & Value

The 2hp Mixer was discontinued in 2020 when 2hp ceased operations, making all their modules, including this one, sought after in the used market. Unlike rare boutique oscillators or filters, the Mixer isn’t flashy, but its utility keeps demand steady. Used units in working condition typically sell for $100–$140, depending on finish (black or silver) and included hardware. New-old-stock units with original packaging can fetch $160 or more, especially in Europe where shipping costs drive up prices.

Failures are rare but not unheard of. The most common issue is cracked solder joints on the power pins, especially if the module was frequently removed or installed. The 3.5mm jacks can also loosen over time, leading to intermittent signals. These are easy fixes for anyone with a soldering iron, but buyers should test all inputs and outputs before purchasing. The knobs are plastic and can crack if over-tightened, so replacements are available but not always exact matches.

Because it’s such a basic module, counterfeits are uncommon—there’s little profit in cloning a $100 passive mixer. However, some third-party clones exist in the DIY community, often labeled as “2HP-style” mixers. These can perform similarly but may use lower-tolerance resistors or cheaper jacks. For purists, original 2hp units are preferred, both for build quality and resale value.

If you’re building a system today, the Mixer remains a smart buy—assuming you can find one. It’s not a centerpiece, but it’s the kind of module you miss the moment it’s gone. And because it does one job so efficiently, it rarely gets in the way of your workflow. That’s the hallmark of good design: invisibility through excellence.