2HP Tuner (2012–2020)
Eleven scales in two horizontal inches. This tiny quantizer gives clear tonal results, but it won't play nice with every signal.
Overview
Plug a drifting, atonal sequence into the 2HP Tuner and it settles into something you could hum. That is what this module does. It isn't flashy, it doesn't edit deeply, and it won't morph scales on a MIDI clock. But in a format where every millimeter counts, it packs a lot of musical use into 2HP of panel space. Eleven fixed scales, from chromatic and pentatonic to octatonic and whole tone, give you enough variety without drowning you in options. The bias control doesn't just transpose up and down the octave ladder. It shifts the root note diatonically, so you can pivot modes on the fly. Want to slide from C major to D Dorian without leaving the key center? Twist the knob.
This isn't a Swiss Army knife. It doesn't let you program custom scales, and it won't track microtonal tunings or just intonation. If your workflow demands those, look to Mutable Instruments' Quadrant or Intellijel's Rainmaker. The Tuner is simple and reliable, and it points toward tonal coherence. It does have quirks. Some users report a subtle "trill" effect when voltages sit on the edge of a quantization threshold, where the output flutters rapidly between adjacent notes. It's not a malfunction, exactly. It's a byproduct of fast switching in a minimal circuit. It can be distracting in legato patches or when feeding sensitive oscillators. Most users find it fades into the background during normal use, and a sample-and-hold at the output can clean it up if needed. The module's compactness also means no dedicated outputs for scale selection or bias CV, so patching in modulation requires stacking or multing. You gain space and lose some patch flexibility.
For skiff builders or anyone running a tight case, the footprint is the big selling point. It slips into gaps where other quantizers wouldn't fit. It's built like all 2HP modules, with a solid extruded aluminum case, a clean PCB layout, and a recessed rotary encoder that feels precise without being fussy. Power draw is negligible: 40mA on +12V, 3mA on -12V. It has no flashing lights and no endless menus.
Specifications
| Manufacturer | 2HP |
| Production Years | 2012–2020 |
| Module Type | Pitch Quantizer |
| Width | 2HP |
| Depth | 45mm |
| Power Supply | Eurorack ±12V |
| +12V Current Draw | 40 mA |
| -12V Current Draw | 3 mA |
| Input Voltage Range | 0V to +5V |
| Input Impedance | 100kΩ |
| Output Voltage | 0V to +5V (quantized) |
| Scales | 11 Preset (Chromatic, Major, Minor, Pentatonic Major, Pentatonic Minor, Whole Tone, Octatonic, Diminished, Blues, Dorian, Phrygian) |
| Control | Rotary Encoder (Scale Selection), Bias Knob (Diatonic Transposition) |
| Inputs | 1x CV Input, 1x Bias CV Input |
| Outputs | 1x Quantized CV Output |
| Color | Silver Anodized Aluminum |
| Mounting | Standard Eurorack 3U |
| Weight | Approx. 50g |
Key Features
Compact Scale Engine with Diatonic Bias
The scale selection covers most harmonic ground without bloat. The octatonic and whole tone scales suit jazz or filmic tension, while Dorian and Phrygian give you modal vamps without external transposition. What sets it apart from other fixed-scale quantizers is the bias control, which shifts the root note within the selected scale rather than transposing chromatically. Turn the knob and you walk the scale step by step, landing on diatonic intervals that keep the harmonic logic intact. Patch a slow LFO into the bias CV input and you get a drifting modal sequence that never hits a wrong note. That works well in ambient or generative patches.
Signal Integrity vs. Edge Cases
Under normal conditions the Tuner quantizes quickly and precisely, locking incoming CV to the nearest scale degree with minimal lag. Its behavior at voltage thresholds has drawn mixed reactions. When an input voltage hovers near the boundary between two notes, say 2.49V vs. 2.50V, the output can oscillate rapidly and produce a trill-like artifact. This isn't unique to the Tuner (some Mutable modules exhibit similar behavior), but it's more noticeable here because there's no smoothing or hysteresis built into the logic. In practice, it only becomes an issue with sample-and-hold sources or unstable CV generators where voltages aren't firmly settled. For sequencer-based patches, it's rarely a problem. Owners report that adding a sample-and-hold module after the Tuner eliminates the flutter entirely and gives a clean, step-accurate output. That costs an extra cable.
Skiff-Ready Simplicity
In a format where 4HP is considered "narrow," 2HP is practically invisible. The Tuner was designed for skiff builders, travelers, and minimalists who need functionality without bulk. It doesn't have multiple outputs, scale memory, or MIDI integration. The rotary encoder clicks through scales with good tactile feedback, and the bias knob has a smooth, linear taper that makes fine adjustments easy. There are no LEDs to indicate scale or note, just the physical controls and your ears. Some see this as a limitation, and others appreciate the focus it forces. You turn a knob and listen instead of scrolling through menus.
Historical Context
The 2HP Tuner arrived in 2012, just as Eurorack was shifting from boutique curiosity to mainstream synth culture. At the time, quantizers were often bulky, multi-function modules buried in larger systems - think Doepfer's A-156 or the Intellijel Metropolis. A dedicated quantizer in 2HP was a radical idea, almost comical. But 2HP, founded by engineer Tony Rolando, had already shown that minimalism could work. Their Rnd and TM modules proved that clever circuit design could deliver expressive tools in very small footprints. The Tuner fit that philosophy. It wasn't the first quantizer in Eurorack, but it was among the first to treat space as a design constraint rather than an afterthought.
Its main competition came from multi-function modules like the Mutable Instruments Shades or Even VCOs with built-in quantization, not from other quantizers. The Tuner carved out a niche by doing one thing well and fitting where others couldn't. It arrived before the quantizer boom of the late 2010s, when modules like the Intellijel Quadravox and Erica Pico Scale offered deep customization. By then, the Tuner had already become a cult favorite. It landed when modular users were still discovering how to use quantization musically, not just technically. Unlike software-based solutions, it offered knob-per-function access.
Collectibility & Value
The 2HP Tuner is no longer in production. It was quietly discontinued around 2020 as the company shifted focus. That has made it a modestly sought-after item, especially among skiff builders and minimalists. Used prices typically range from $120 to $180, depending on condition and seller location. Units with clean faceplates and responsive encoders hold value best. Those with scratched knobs or wobbly shafts tend to sell closer to the lower end. It's a passive logic module with no moving parts beyond the encoder, so failure points are minimal. The most common issue reported is encoder jitter, where the scale selection skips or misreads. Contact cleaner or a replacement shaft can usually fix it. There are no known batch defects or widespread reliability concerns.
When buying, test the encoder's action and make sure all 11 scales are accessible without skipping. Check the bias knob for smooth rotation and verify that CV input tracking is consistent across multiple octaves. The module has no calibration trimmers, so inconsistent quantization usually points to a faulty input buffer or a power issue, not user-adjustable error. Original packaging isn't common, but it can add $20-$30 in value for collectors. Given its niche appeal, the Tuner isn't likely to become a high-value grail, but it's also not going to plummet in price, since steady demand keeps it up.
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