2hp Mixer (2008–2020)

Name: 2hp Mixer
Brand: 2hp

Four channels, one output, and a faceplate so tiny it disappears.

Overview

The 2hp Mixer is 2HP wide, one of the narrowest functional modules in Eurorack. It's a sliver of brushed aluminum that fits where other modules won't. Plug in four audio or CV signals, set their levels with the four knobs, and the sum goes to a single output. That's all it does. No panning, no mute buttons, no trim pots, no polarity switches. There's no op-amp circus under the hood and no digital brain, just passive summing with minimal buffering. The sound is transparent with a slight analog warmth.

Despite its size, it's not a toy. The Mixer handles both audio and control voltage with equal competence. It sums oscillators, blends modulation sources, or collapses a stereo field to mono before a filter or effects chain. It's the module for when you've run out of mix bus space but still need to glue a few elements together. At 2hp, you can fit two or three of them in the space most modules take up alone.

It's not the loudest mixer out there, and you shouldn't expect pro-level headroom. 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 exploit for saturation. For quiet, clean summing, it's excellent. For aggressive blending, it's forgiving. Because it's passive-first, it loads the output of whatever feeds it slightly, which can subtly round off sharp transients. Sometimes that's a feature and sometimes it's a quirk, depending on the 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 keeps noise low and power draw minimal, and it avoids the phase shifts and crosstalk that can plague poorly designed active mixers. The resistors are precision 1% tolerance, so each channel contributes evenly. Because the front end is passive, the module presents a consistent load to upstream modules. That 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 act as a subtle tonal tweak.

Compact Form Factor

At 2HP, this module saves a lot of space. It's narrower than a single banana jack on many cases. That makes it a good fit 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, which is nearly impossible with standard 8-10HP mixers. The knobs sit close together, so large fingers or thick cables can make patching a bit fiddly. Most users accept the tight quarters for the density.

Audio and CV Versatility

It's marketed as an audio mixer, but 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. It's DC-coupled, so there's no low-frequency rolloff and slow CV signals pass through unchanged. That makes it useful for adding offsets, averaging modulation sources, or building complex control voltages from simple ones. It's not a quantizer or logic processor, but in a pinch it can do basic analog computation.

Historical Context

The 2hp Mixer arrived in 2008, as Eurorack was shifting from boutique curiosity to mainstream modular format. At the time, most mixers were 8HP or wider, often with 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 because it did less in less space. It appealed to minimalists, skiff builders, and anyone tired of giving up 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. Modules were getting bigger and more complex, and the Mixer went the other way.

Collectibility & Value

The 2hp Mixer was discontinued in 2020 when 2hp ceased operations, and all their modules, this one included, are now sought after on the used market. Unlike rare boutique oscillators or filters, the Mixer isn't flashy, but demand stays 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 and cause intermittent signals. Both are easy fixes with a soldering iron, but buyers should test all inputs and outputs before purchasing. The knobs are plastic and can crack if over-tightened. Replacements are available but not always exact matches.

Counterfeits are uncommon, since there's little profit in cloning a $100 passive mixer. 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. Original 2hp units are preferred for build quality and resale value.

If you're building a system today, the Mixer is still a smart buy, assuming you can find one. It's not a centerpiece. Because it does one job so efficiently, it rarely gets in the way of your workflow.