ADDAC System ADDAC120BS

4-string Eurorack synthesizer - Basic System Skiff 122HP

• ADDAC String System Basic for Eurorack: headstock, bridge, humbucker pickup, and rotary exciter
• Strings can be installed just like on a traditional guitar, with gauges up to .055
• 4 locking tuners for quick and precise string installation
• Integrated humbucker pickup with Tone and Volume controls and a LOW/HIGH gain switch
• Rotary Exciter with a 7,000 RPM brushless motor for magnetic excitation of the strings
• Included accessories: .010-.046 string set, bow arch attachment, and small resonators
• Compact format: 122HP total, ideal for Eurorack skiffs

The ADDAC120BS is the Basic String System by ADDAC System, a modular Eurorack ecosystem that transforms real strings into a synthesizable and processable sound source. The system combines three modules—the ADDAC120 Headstock & Bridge, the ADDAC121 Humbucker, and the ADDAC126 Rotary Exciter—designed to be installed together in a 122HP skiff, offering a complete starting point for anyone who wants to explore string-based synthesis within their modular system.

ADDAC120 Headstock & Bridge: The foundation of your Eurorack string instrument

The ADDAC120 forms the physical foundation of the system—a Headstock & Bridge module that accommodates strings with gauges up to .055. The strings are installed exactly as on a guitar: the user is free to choose their preferred string set and tuning. The headstock features 4 locking tuners to make string installation faster and easier; the string holes can also be enlarged to accommodate thicker strings.

Bow Arch Attachment and Small Resonators: Harmonics and Sound Textures

The set includes a Bow Arch Attachment, which raises the two center strings, allowing a bow to reach each string individually, and Small Resonators, which are simple yet extremely effective at adding harmonics to the unwound strings. Each resonator applied generates a new partial: by adding more, the timbre becomes progressively more complex, resulting in sounds reminiscent of a bell. The position of the resonator on the string defines the pitch of each harmonic.

ADDAC120 Specifications: stainless steel panels, 17HP headstock, 6HP bridge, headstock depth 0 cm, bridge depth 2 cm.

ADDAC121 Humbucker: the pickup that transforms strings into a synth signal

The ADDAC121 is the system’s humbucker pickup module, equipped with Tone and Volume controls and a LOW/HIGH gain switch to add saturation to the signal. A built-in preamp boosts the volume to synth level, ready for processing in the rest of the Eurorack system. The pickup’s height is adjustable via the mounting screws, and it can also be removed for manual use.

ADDAC121 Technical Specifications

10HP, depth 2.5 cm, current draw 30 mA at +12V and 30 mA at -12V.

ADDAC126 Rotary Exciter: Magnetic String Excitation for Eurorack

The Rotary Exciter features a 7,000 RPM brushless motor that rotates a surface equipped with four oppositely polarized magnets, generating a rotating magnetic field. When the rotation speed matches the fundamental frequency or harmonics of a string, the string is forced to vibrate, creating sonic textures that would otherwise be impossible to achieve manually. A Speed knob and a CV input allow for nonlinear control of the motor speed.

ADDAC126 Technical Specifications

10HP, depth 2.5 cm, current draw 100 mA at +12V.

Technical Specifications

• Overall Size: 122HP (skiff)
• ADDAC120 Headstock: 17HP, depth 0 cm
• ADDAC120 Bridge: 6HP, depth 2 cm, stainless steel panels
• ADDAC121 Humbucker: 10HP, depth 2.5 cm, 30 mA at +12V, 30 mA at -12V
• ADDAC126 Rotary Exciter: 10HP, depth 2.5 cm, 100 mA at +12V, 7000 RPM brushless motor
• Supported string gauge: up to .055
• Included accessories: .010–.046 string set, Bow Arch Attachment, Small Resonators