The DSM01 Curtis Filter from Dave Smith Instruments is a filter module for modular synthesizer. Housed in an 8 HP Eurorack-format, the module features Dave Smith's signature filter sound, found in everything from his vintage Sequential synthesizers to the more recent offerings such as the Prophet 12.
The filter is a resonant low-pass design that can be switched between -12 dB and -24 dB operation and driven into self-oscillation in -24 dB mode. A boost switch allows for overdriving the input stage for more aggressive coloration.
In addition to its Curtis filter, the DSM01 provides its own responsive, low-noise VCA with LED CV indicator. There are two separate outputs, one pre-amplifier and the other post-amplifier. This not only provides added signal routing flexibility, but also frees the host system's existing VCAs for other tasks.