Doepfer A-111-4 Quad Precision VCO

Doepfer A-111-4 Quad Precision VCO – High-Precision Modular Sound Generator for Discerning Sound Designers

With the Doepfer A-111-4 Quad Precision VCO, the renowned German manufacturer Doepfer presents a powerful Eurorack module designed for professional musicians, sound tinkerers, and modular synthesizer enthusiasts. This module consists of four high-quality, voltage-controlled oscillators (VCOs) and opens up a wide range of sonic possibilities—whether for complex frequency modulations, polyphonic applications, or precisely tuned monophonic setups.

Thanks to its well-thought-out structure and high-precision design, the Doepfer A-111-4 is particularly well-suited for modular setups where sound quality and flexibility are top priorities. Whether in the studio or on stage—this quad VCO proves to be a versatile tool with musical depth in every situation.

Doepfer – Quality and Innovation from Germany

Doepfer has been a staple in the world of modular synthesizers for decades and is synonymous with high-quality, reliable, and innovative Eurorack modules. Headquartered in Gräfelfing near Munich, the company has made a name for itself worldwide and is now an indispensable part of professional modular systems. What sets Doepfer modules apart is the combination of classic circuit design, precise craftsmanship, and a clear focus on functionality.

This expertise is particularly evident in the Doepfer A-111-4 Quad Precision VCO: The four VCOs are based on the legendary CEM3340 chip, which was already used in vintage synthesizers such as the Roland SH-101 and the Sequential Prophet-5. Doepfer harnesses the full potential of this component and complements it with a well-thought-out control concept and maximum tuning stability thanks to an independent power supply for each oscillator.

Technical Details of the Doepfer A-111-4 Quad Precision VCO

At the heart of the A-111-4 are four identical, high-precision VCOs with 1V/octave tracking over at least ten octaves. Each oscillator has its own controls and inputs and outputs, making the module extremely versatile. In addition, a master section offers further control options and outputs for combined signals from all four VCOs.

The oscillators use a triangle core and offer classic waveforms such as triangle, sawtooth, and square. Each of these outputs is available both per VCO and as a sum signal of the oscillators that are not patched separately. This allows for both monophonic and complex polyphonic setups.

For pitch control, each VCO features a three-position octave switch (+1, 0, -1 octave) and a sensitive tune control. The internal range of the tune potentiometer can be selected via a jumper: approximately 2 semitones, approximately 1 octave, or approximately 4 octaves—ideal for a variety of musical requirements and fine-tuning.

Particularly noteworthy is the frequency modulation capability: a separate control input per VCO allows for either exponential or linear modulation. Pulse-width modulation (PM) can also be activated via an internal jumper. The modulation depth can be precisely adjusted using a control.

Another highlight is the sync input. Here, a jumper switch allows you to choose between hard and soft sync—the latter enables more subtle synchronized sounds, while hard sync produces more dramatic effects. The CEM3340 chip used supports the classic hard-sync type for particularly distinctive timbres.

Thanks to its precise tracking and excellent tuning stability—supported by a separate power supply for each individual oscillator—the A-111-4 is also suitable for applications where absolute pitch accuracy is essential. The bus CV function can be activated via a jumper and allows for convenient control via a Eurorack system.

Why You Should Buy the Doepfer A-111-4 Quad Precision VCO

The Doepfer A-111-4 Quad Precision VCO is more than just an oscillator module—it’s a powerful sound engine that excels in both monophonic and polyphonic patch configurations. If you’re looking for a flexible, high-quality, and sonically powerful VCO module, you’ve found it here.

The ability to control each oscillator individually or collectively opens up creative possibilities for modular compositions. Whether classic synthesizer sounds, complex frequency modulations, paraphonic sound structures, or fully polyphonic patches: This module delivers a clean, assertive sound with excellent tuning stability in every situation.

For users of the Doepfer A-190-5 MIDI/USB-CV interface, additional possibilities arise: When used together, both paraphonic and fully polyphonic patches can be created—a rare option in the modular Eurorack world.

Last but not least, the module impresses with its robust build quality, intuitive operation, and well-thought-out layout. A true workhorse in the studio—with the A-111-4, modular sound design becomes a musical journey of discovery.

Features:

• Four high-quality precision VCOs in a single module
• CEM3340 chip with a triangular waveform core
• 1 V/octave tracking over at least 10 octaves
• Independent controls and outputs per VCO
• Master section with combined outputs and control functions
• Triangle, sawtooth, and square waveforms
• Individual outputs and sum outputs
• Octave switch (+1/0/-1) for each VCO
• Tune control with three selectable ranges
• Frequency modulation: exponential, linear, or pulse width (via jumper)
• Modulation depth control
• Sync input with hard or soft sync (jumper)
• Independent power supply for optimal tuning stability
• CV output for the sum signal of the control voltages
• Bus CV-capable (selectable via jumper)
• Ideal for monophonic, paraphonic, and polyphonic applications

Specs:

• Type: Module
• Theme: Recording and Studio

Further links:

• Print View