2hp MIDI (2013–2024)

A tiny translator that speaks MIDI and Eurorack. It turns your laptop into a synth command center without the cable spaghetti.

Overview

The 2hp MIDI is only two horizontal pitch units wide. Slide it into your rack, plug in a USB mini cable, and your modular system is talking to your DAW, your MIDI keyboard, or that old Roland groovebox. No firmware updates, no menu diving, no drivers. A blinking red LED pulses as MIDI data comes in. You don't set up the 2hp MIDI. You plug it in and it works, which is not something you can say about every USB-MIDI-CV translator.

Don't mistake the plug-and-play ease for limited functionality. Behind the minimalist silver or black faceplate, the module parses MIDI into four operating modes: monophonic (one CV/gate pair tracking your lead lines), duophonic (two-note polyphony with dedicated CV outs), dual mono (two independent monophonic channels, good for layering), and quad trigger (four independent gate pulses from a single MIDI channel, ideal for drum sequencing). Each mode changes how your modular system interprets incoming data. Switching between them means holding a button during power-up. That was rare in the early 2010s Eurorack boom, when many MIDI interfaces demanded complex configuration or external hosts.

At only 2hp wide, it's skiff-friendly, power-sipping, and mechanically simple. There are no moving parts, no patchable configuration inputs, no parameter screens. It draws a negligible 27 mA from the +12V rail and nothing from the 5V line, which makes it one of the most efficient MIDI-to-CV converters ever made. It's class-compliant, so it shows up as a standard MIDI device on Mac, Windows, and Linux with no special drivers. That reliability made it a staple in desktop setups, travel rigs, and starter systems where space and stability were at a premium.

It has trade-offs. The 12-bit resolution on the CV outputs is adequate but not stellar by modern standards. It's fine for pitch, but less ideal for smooth filter sweeps or nuanced modulation. The quad trigger mode doesn't offer per-step velocity or aftertouch routing, which limits expressiveness for advanced performers. It also lacks internal quantization, so if your MIDI source plays slightly sharp or flat, your VCOs will follow it off-key. For bridging digital control and analog synthesis with zero fuss, it remains one of the most trusted translators in the Eurorack ecosystem.

Specifications

Manufacturer	2hp
Production Years	2013–2024
Original Price	$109
Width	2hp
Depth	45mm
Power Consumption (+12V)	27 mA
Power Consumption (-12V)	3 mA
Power Consumption (5V)	0 mA
CV Outputs	2 (12-bit resolution)
Gate Outputs	2
MIDI Input	USB Mini-B
MIDI Output	None (MIDI-to-CV only)
Operating Modes	Monophonic, Duophonic, Dual Mono, Quad Trigger
MIDI Message Support	Note On/Off, MIDI Clock, Control Change (CC)
Class Compliant	Yes (Mac, PC, Linux)
Status Indicator	LED for MIDI activity
Weight	Not specified
Manual	Available at twohp.com

Key Features

Four Modes, One Purpose

The four operating modes are where the 2hp MIDI gets smart. In monophonic mode, it tracks a single pitch with CV and gate, which suits leads and basslines. In duophonic, it splits incoming MIDI notes across two CV outputs, so you can play two oscillators in harmony or stack two different voices. Dual mono turns it into two independent monophonic converters, handy for driving separate synth chains from a MIDI keyboard's split zones. In quad trigger mode, a single MIDI channel can trigger four separate gate outputs, which makes it an easy fit for drum modules like the 2hp Drums or Doepfer A-174-2. No other module in this size class offered that level of mode flexibility without external logic or firmware tweaks.

USB Mini-B: Blessing and Limitation

The USB Mini-B connector, now nearly obsolete, was forward-thinking and slightly inconvenient at launch. In 2013, most MIDI interfaces still relied on bulky 5-pin DIN connectors and needed additional USB-to-MIDI adapters to link with computers. The 2hp MIDI went straight to USB, but that created a new bottleneck. To connect it to traditional MIDI gear like a Juno-60 or a TR-8, you needed a USB host (a computer or a dedicated USB-MIDI hub) in the signal chain. That made it less useful as a standalone hardware bridge. Owners of standalone MIDI gear learned that it was built for computer integration, not vintage synth patching - unless they were willing to carry a Raspberry Pi in the gig bag.

Class-Compliant Simplicity

Many USB audio and MIDI devices of the time required proprietary drivers or firmware updates. The 2hp MIDI is class-compliant. It appears as a standard MIDI device the moment you plug it in, with no installation and no kernel panics on macOS. That made it a favorite in live setups where gear failure isn't an option. Service technicians note that firmware issues are nearly nonexistent, and the lack of user-updatable code means there's almost nothing to go wrong. It's the kind of module you install once and forget about, in a system full of temperamental oscillators and drifting filters.

Historical Context

The 2hp MIDI launched in 2013, when Eurorack was spreading beyond boutique studios into home setups, laptop-based producers, and hybrid rigs. Integrating modular with digital workflows was still a pain. Most MIDI-to-CV solutions were bulky, expensive, or required deep technical knowledge. The 2hp MIDI arrived as part of a wave of "utility minimalism" from designers like 2hp, Intellijel, and Mutable Instruments, who believed that small, focused modules could solve big problems. It wasn't the first USB-to-CV converter, but it was among the first to combine tiny size, low power draw, and rock-solid reliability in a single package.

Its main competitors at the time, like the Kenton Pro Solo or the Doepfer MSY2, offered more CV outputs or DIN MIDI support. They were also larger, more power-hungry, and often required configuration via DIP switches or software. The 2hp MIDI took a "just works" approach that suited beginners and veterans alike. It also arrived just as DAW-based MIDI sequencing became the norm, so producers could extend their digital arrangements into the analog domain without re-sequencing everything in hardware.

The module’s design reflects 2hp’s broader philosophy: minimalism with purpose. Founded by engineer Tony Rolando (also known for his work on the Korg Monotron), 2hp built a reputation for elegant, no-nonsense modules that solved specific problems without overengineering. The MIDI module is a perfect example—no flashy displays, no patchable modes, no hidden menus. It does one thing and does it well, embodying the “less but better” ethos that defined much of the 2010s Eurorack renaissance.

Collectibility & Value

As of 2024, the 2hp MIDI is officially discontinued, ending a decade-long production run. It's not a rare module. On the used market, expect to pay $60 - $80 for a working unit in good cosmetic shape, with silver-face models sometimes commanding a slight premium over black. Units with damaged USB ports or non-functional LEDs, often from repeated plugging, tend to sell for $40 or less. Repairs are usually straightforward since the circuit is simple and well-documented.

Common failures are few. The USB Mini-B port is the most vulnerable component, prone to wear from frequent insertion and removal. Some users report intermittent connection issues after years of use, often fixable by resoldering the port or replacing it. The status LED has been known to fail on older units, though this doesn't affect functionality, only the visual feedback. There are no known issues with the CV or gate outputs degrading over time, and with no internal battery or memory, there's no data loss or firmware corruption to worry about.

For buyers, the key check is the USB port's physical stability and the LED's responsiveness. Plug it in and send MIDI. Any note should make the LED blink. If it doesn't, the issue is likely the USB interface chip or port. Also verify that the module powers correctly from the Eurorack bus. It draws minimal current, but a faulty power connector can cause erratic behavior. Given its simplicity, most problems are mechanical rather than electronic.

Despite being discontinued, the 2hp MIDI is still a practical choice for a compact or computer-integrated system. It won't replace more advanced converters like the Expert Sleepers FH-2 or the Intellijel uMidi, which offer higher CV resolution, more outputs, and deeper MIDI mapping. For straightforward, space-saving MIDI integration, it's still one of the most cost-effective options available.