MIDI to CV Converter Voltage Standards

MIDI to Control Voltage (CV) converters bridge modern digital gear and analog synthesizers by translating digital MIDI messages into analog control voltages. This article provides a comprehensive overview of the primary voltage standards supported by these converters, including pitch standards like 1V/Octave and Hz/V, gate and trigger formats such as V-Trigger and S-Trigger, and standard modulation voltage ranges.

Pitch CV Standards

Analog synthesizers rely on specific voltage curves to track pitch accurately across keys. Most MIDI to CV converters support one or both of the following primary standards:

• Volt-per-Octave (1V/Oct): This is the most common standard, utilized by Eurorack modular systems, Moog, Roland, ARP, and Sequential Circuits. In this linear standard, an increase of one volt raises the oscillator's pitch by exactly one octave (roughly 0.0833 volts per semitone). Pitch CV outputs typically range from 0V to +10V (spanning 10 octaves) or -5V to +5V.
• Hertz-per-Volt (Hz/V): Popularized by vintage Korg (such as the MS-20) and Yamaha synthesizers, this exponential standard doubles the voltage for every octave increase (e.g., 1V, 2V, 4V, 8V). Converters capable of Hz/V typically provide a range from 0V to +8V or 0V to +10V.
• 1.2V-per-Octave: Less common, this standard is primarily used by Buchla modular systems. Some flexible or high-end converters include specific calibration options to output 1.2V per octave.

Gate and Trigger Standards

Gate and trigger signals tell the receiving synthesizer when a note begins, how long it is held, and when it ends. Converters generally support two variations:

• V-Trigger (Voltage Trigger / Standard Gate): The standard across Eurorack, Roland, and modern analog gear. The signal rests at 0V (off) and switches to a positive voltage when a key is pressed. Output gates typically generate +5V, +10V, or +12V pulses.
• S-Trigger (Switch Trigger): Common on vintage Moog and Korg synthesizers, this system uses an inverted, short-to-ground mechanism. The line rests at a positive voltage (or open circuit) and drops to 0V (ground) when a note is active. Many modern converters allow users to toggle their gate outputs between V-Trigger and S-Trigger via software or hardware jumpers.

Modulation and Auxiliary CV

Beyond pitch and gates, MIDI to CV converters translate continuous controller (CC) messages, velocity, aftertouch, and pitch bend into analog voltages using two primary configurations:

• Unipolar Voltages (0V to +5V or 0V to +10V): Typically used for note velocity, aftertouch, and general MIDI CC mapping to modulate filter cutoffs, volume levels, or envelope stages.
• Bipolar Voltages (-5V to +5V): Primarily used for pitch bend and low-frequency oscillators (LFOs), where the voltage needs to swing both above and below a center point of 0V.

Clock and Sync Signals

For synchronization, converters translate MIDI clock data into analog clock pulses. These outputs typically deliver sharp +5V pulses configured to match standard timing intervals, such as 24 PPQN (Pulses Per Quarter Note) for DIN Sync, 48 PPQN, or simplified 1 PPQN / 2 PPQN triggers for vintage sequencers and drum machines.