Behringer TD-3-MO-SR

Behringer TD-3-MO-SR Analog Bass Line Synthesizer

The Behringer TD-3-MO-SR is a "modded out" analog bass line synthesizer that brings the legendary TB-303 sound into modern studios with expanded controls and connectivity. Its pure analog signal path with authentic VCO, VCF, and VCA circuitry provides those classic squelching bass tones that shaped acid house, electro-funk, and techno. This model is aimed at producers and sound designers seeking vintage 303 character with modern creative flexibility.

Community-Inspired Mods Built Into the Hardware

What sets this synthesizer apart is the suite of popular third-party modifications built right into the circuit board. You get a MIDI-controllable filter, variable slide time, three-mode sweep speed switch, accent sweep switch, and soft attack control for a greatly expanded sonic range. Experiment with aggressive new textures using the post-VCA "muffler" distortion and dedicated filter FM, or add extra depth with a sub-oscillator button for a heavier bass foundation.

Analog VCO Engine — Pure Subtractive Synthesis

Inside this silver desktop module, a single analog voltage-controlled oscillator offers instant tonal variation by switching between sawtooth and square waves. The matched transistors ensure the sound engine delivers the rich analog character expected from this family of synths.

• Oscillators: Analog VCO with selectable sawtooth and square waveforms
• Sub-oscillator button drops in an extra octave, making basses more powerful and resonant in the mix.
• Sound Engine: Analog Subtractive synthesis with matched transistors

4-Pole Resonant Filter — Split Envelope Control

The onboard 4-pole resonant low-pass filter shapes every sound, while the split envelope architecture allows you to control VCF and VCA separately—an upgrade over the classic design.

• Filter: 4-pole resonant low-pass VCF with cutoff, resonance, envelope, decay, and accent controls
• Envelope: EG with separate VCF decay, VCA decay, and soft attack controls
• Modulation possibilities expand with the integrated LFO for filter and pitch movement.
• Polyphony: Monophonic (1 voice), expandable to 16 voices via Poly Chain

16-Step Sequencer — Compact Desktop Footprint

Patterns can be programmed efficiently using a sequencer with several modes and ample storage. The compact body fits into almost any studio or live setup.

• Sequencer: 16-step, 7-track with 250 user pattern slots across 4 groups
• Play and enter patterns live using the 13 mini key buttons for hands-on control.
• CV/Gate, Filter FM, Filter CV, Accent, and Slide I/O, plus 5-pin DIN MIDI and USB-MIDI, allow flexible integration into hardware and DAW environments.
• Dimensions: 305 × 165 × 56 mm, weight 0.9 kg

For Acid, Techno, and House Producers

This instrument is designed for electronic music producers, sound designers, and live performers who need unmistakable acid bass with workflow improvements. If you're building your first hardware setup, the layout and intuitive sequencer make it easy to get started. More advanced producers and DJs can benefit from expanded filter controls, MIDI, and the Eurorack-friendly patchbay.

From TB-303 Legacy to Behringer's Modded-Out Vision

The TD-3-MO-SR traces its DNA to the Roland TB-303, a 1981 creation for guitarists that became the icon of acid house after circuit benders revealed its potential. Behringer’s “modded out” approach packages the most popular community tweaks into an affordable, factory-built synth. Uli Behringer founded the company after building his own synthesizer at 17, growing the brand from a Swiss workshop to a global music tech leader.