The Analogue Systems RS-500N is the only officially licensed EMS diode lowpass filter in Eurorack format, faithfully recreating the legendary filter from the iconic VCS3 and Synthi AKS synthesizers. This Eurorack-compatible module delivers the unmistakable vintage tone and behavior of the original EMS circuits, with some welcome modern upgrades for today’s modular users.

Switch between two historically distinct filter types:

• Pre-1974 (-18dB/oct slope): raw, organic, and slightly unstable

• Post-1974 (-24dB/oct slope): tighter, more refined response

While the original EMS design included hidden options for voltage-controlled resonance, the RS-500e makes them fully accessible. You now get CV control over both cutoff and resonance, allowing for high-speed modulation and dynamic filter sweeps impossible on the originals. An additional CV response speed switch gives the option of faster tracking, ideal for snappy envelopes or sequenced modulation.

Signal input and output levels are manually adjustable, offering flexible gain staging when integrating with modern systems. The updated panel and power connector ensure full compatibility with Doepfer-style Eurorack systems (using Analogue Systems-to-Doepfer power adapter if needed).

Built under official license from EMS.