The attached manual is for the 2hp Switch, a 4-in / 1-out voltage-controlled signal router. It can switch audio, CV, or gate signals, and the active input can be chosen either by the SEL knob or by SEL CV.
Even though Switch is not a pitch generator by itself, it is very useful for melody construction, because melodies in Eurorack are often built by choosing between: - different pitch CV sources - different rhythmic gate streams - different transpositions - different quantized sequences - different audio voices playing melodic material
Switch is basically a decision point in the patch. It lets you create melodies by selecting which source is currently active.
Patch four different pitch-related CVs into the inputs: - Input 1: a sequencer line - Input 2: a random voltage source - Input 3: a transposed copy of the sequencer - Input 4: a slow modulation source into a quantizer
Then send OUT to: - a quantizer input, then to oscillator 1V/oct - or directly to an oscillator if the voltages are already musical
You get a melody that can jump between four different pitch behaviors.
This is one of the easiest ways to create: - verse/chorus-like variation - call-and-response melodic motion - controlled unpredictability
A very musical patch is to mult one melodic CV sequence into several processors: - Input 1: original sequence - Input 2: sequence + 2 semitones - Input 3: sequence + 5 semitones - Input 4: sequence + 7 semitones
Send the output to your oscillator pitch path.
The same melodic contour is preserved, but the active harmony changes.
This gives you: - modal shifts - chord-root movement - bassline variation - instant harmonic structure from one phrase
If you clock the switching rhythmically, you can make the melody outline harmonic changes without needing a second sequencer.
If you have a quantizer in the system, Switch becomes especially useful.
This makes four raw sources become one playable melodic stream.
This is cleaner if each source already has a distinct scale or pattern.
You can move between: - stable melody - semi-random melody - arpeggio-like motion - transposed variations
Melody is not just pitch; it is also when notes happen.
Patch four gate or trigger sources into Switch: - Input 1: straight clock division - Input 2: syncopated trigger pattern - Input 3: random triggers - Input 4: Euclidean rhythm
Then send OUT to: - envelope trigger input - sequencer advance input - sample-and-hold trigger - quantizer trigger, if applicable
You can keep the same pitch source but radically change the melodic phrasing.
A single pitch sequence can sound like entirely different melodies when the note timing changes.
Because Switch also handles audio, you can patch: - Input 1: sine lead - Input 2: square bass voice - Input 3: filtered pluck - Input 4: FM voice
Then switch which voice reaches the output.
One melodic line can jump between different timbres or instruments.
This is great for: - live arrangement - fills - alternating lead sounds - turning one sequence into a multi-voice phrase
Because the module switches quickly, it can create abrupt, stylized phrase changes.
The most interesting part of this module is SEL CV.
Since the SEL CV is added to the knob position, you can offset the range manually and then animate selection with another CV source.
Patch a CV source to SEL: - stepped random voltage - sequencer CV lane - LFO - sample & hold - gate-derived stepped voltage
The chosen melodic source changes over time automatically.
This turns Switch into a kind of meta-sequencer, where it sequences which sequence is active.
Goal: build a melody from four phrase fragments.
Each incoming control step at SEL chooses a different phrase source. Instead of one linear melody, you get a modular phrase system.
Goal: use one sequence to imply chord changes.
Take one sequence and create 4 versions: - Input 1: root - Input 2: +3 or +4 semitones - Input 3: +7 semitones - Input 4: +12 semitones
The same melodic shape moves through harmonic positions.
Goal: change note rhythm while keeping pitch constant.
The same pitch material gets different rhythmic articulation depending on which gate stream is active.
Goal: mix predictable and unpredictable melody sources.
The melodic voice alternates between stable and unstable sources.
Goal: one melody, multiple instrumental identities.
Different notes or note groups appear with different timbres.
If the inputs contain free CV rather than tuned pitch, the output may jump to non-musical voltages. Sending OUT to a quantizer makes the result much more melodic.
If SEL CV moves too freely, the routing may change too often. For more musical results: - use stepped voltages - sample-and-hold - sequencer rows - clock divisions
Because the CV is added to the knob position, the knob can act like a manual “center” or source preference. This is useful in performance.
Switch is especially strong at the phrase level: - choose which melody source is active this bar - choose which rhythm drives the melody - choose which transposition is active in the chorus
So it is less a note sequencer, and more a melodic structure and variation tool.
This is a router, not a sequencer or quantizer. Its power comes from how you combine it with those modules.
The 2hp Switch is best understood as a melodic selector and structure tool. It creates musical interest by choosing among: - multiple pitch sources - transposed variants - different rhythm generators - different melodic voices
In a Eurorack patch, that makes it extremely useful for: - evolving melodies - performance variation - generative composition - compact harmonic movement
If you want, I can also turn this into:
1. a beginner-friendly patch recipe list,
2. an advanced generative melody guide, or
3. a “best modules to pair with 2hp Switch” companion chart.