LINNAEUS

Linnaeus's thru-zero FM depth is set by the modulation index. The internal modulation oscillator's output is summed with the External Linear FM input and fed to a modulation-index VCA, which scales the linear thru-zero index from zero up to 8X. The index is itself voltage-controllable through an attenuverted CV input. At a low index you get gentle vibrato or subtle timbral movement. At a high index you reach deep, clangorous FM and percussive metallic tones. Because both the modulation-source level and the index are voltage-controllable, you can play FM depth dynamically from envelopes or other CV.

Yes. An integrated modulation oscillator gives continuously variable waveforms from off through sine, triangle, sawtooth and square. Its frequency is exponentially voltage-controllable and can optionally lock to track the filter's cutoff. You can get dramatic FM filter effects without any external modulation source.

Yes, with one distinction. Linnaeus has stereo inputs and outputs and can process a stereo signal or two independent mono signals. The two channels share the filter's cutoff and resonant frequency. Their response characteristics (LP/BP/HP/notch/shelving) can be set independently per channel through dedicated enable switches. This allows creative stereo effects, for example lowpass on the left channel and highpass on the right.

Press and hold the Egg button and Linnaeus enters an alternate firmware mode. It becomes a self-contained stereo oscillator and FM percussion voice with no audio input required. Trigger the filter with gate signals to create pitched percussion, metallic tones and FM textures. Some users have built entire sample libraries from Ping Mode alone.

Yes. Linnaeus has a precise 1V/Oct input and tracks accurately from sub-audio to ultrasonic frequencies, across a range well beyond 10 octaves.

Linnaeus's cutoff and resonant frequency is exponentially voltage-controllable from sub-audio to ultrasonic, driven by a precise 1V/oct input and an attenuverted CV input. Its resonant gain (Q) is exponentially voltage-controllable from 0 dB to more than 60 dB, through a 6 dB/V input and an attenuverted CV input. That range lets Linnaeus work as a slow, sweepable tone-shaping filter and as a sharp, high-Q resonator that can ring or self-oscillate for tuned tones. Because both frequency and Q respond to exponential control, you can play the resonant peak as a pitched voice across a very wide span. The exponential Q gives fine command over resonance, from gentle emphasis up through extreme resonance.

Evolution is a lowpass-only analog ladder filter with variable slope and drive. Linnaeus is a multimode state-variable filter with thru-zero FM and stereo I/O. Evolution is strong on thick, warm analog lowpass character. Linnaeus is more versatile for general filtering and stereo processing. In a single-filter system Linnaeus covers more ground. In a dedicated lowpass role Evolution has deeper character.

Morpheus is digital and Linnaeus is analog. Morpheus offers 289 filter configurations and 3D morphing, which makes it a sound-design tool. Linnaeus is a more immediate, hands-on filter with thru-zero FM and stereo operation. Morpheus reaches sounds that traditional filters cannot. Linnaeus does traditional filtering well and adds thru-zero FM on top.

Linnaeus is 16 HP wide and 25 mm deep. It fits any standard Eurorack case, including shallow skiffs.

Linnaeus draws 155 mA on +12V and 36 mA on -12V. It uses a standard 16-pin Doepfer-style connector, needs no +5V rail and is reverse-polarity protected.

Linnaeus puts nearly every parameter under voltage control. Frequency has a precise 1V/oct input plus an attenuverted CV input. Resonance (Q) has a 6 dB/V input and an attenuverted CV input. An External Linear FM input handles thru-zero modulation, with an attenuverted CV input for the modulation index. Each channel's response can be swept by an attenuverted response CV input, enabled per channel by the Response CV Enable controls. The internal modulation oscillator's frequency also has an attenuverted CV input. Audio connections are stereo in and stereo out. The input labeled Ext Lin CV is also the port you play the firmware-update WAV into. Because most CV inputs are attenuverted, you set both the amount and the polarity of each modulation source.

Linnaeus's current firmware is v1.03 (download: v1.03 WAV), released in May 2020. It corrected an issue with Manual and External Ping Mode.

Press and hold the Right Response Enable button. After about 2 seconds, the top 4 LEDs show the version in binary. You do not need to read binary. Just compare the LED pattern to the latest version on the product page. The current version is 1.03_200529, whose LED pattern is Off, Off, On, On. If your module shows an earlier pattern and you use Ping Mode, updating is worthwhile. To update, play the firmware WAV into the Ext Lin CV input: power on while holding the Left Response CV Enable and Left Response Enable buttons, press Track, then play the file and follow the LED prompts.

Play the firmware WAV file (download: v1.03 WAV) into the module's Ext Lin CV input from a computer, phone or audio interface. A few caveats matter:

• On Mac, Safari can corrupt the audio stream. Use QuickTime Player or another application instead.
• Quit all other apps that produce audio first.
• If you use an audio interface, make sure it outputs line level.
• If you use a phone, put it in Airplane Mode so notifications do not interrupt the stream.

Start with the Linnaeus product page, which has audio demos. The community ModWiggler thread also has many user examples and patches. Rossum continues to add demo content.