Common Questions, Answered

Rossum Electro-Music was founded by Dave Rossum, co-founder of E-mu Systems. At E-mu, Dave designed the E-mu Modular System, the Emulator series of samplers, the SP-12 and SP-1200 sampling drum machines and the Morpheus Z-Plane Synthesizer. Rossum Electro-Music continues that engineering legacy with a line of Eurorack modules and the SP-1200 Reissue family.

Dave Rossum co-founded E-mu Systems in the 1970s and led the design of its landmark instruments. Rossum Electro-Music is Dave's current company, founded after E-mu was dissolved. Several Rossum products draw directly on E-mu heritage. The SP-1200 recreates the original E-mu drum machine and Morpheus implements the Z-Plane filter technology from the E-mu Morpheus rack synthesizer.

Dave Rossum co-founded E-mu Systems and led the design of a string of industry-defining instruments: the E-mu Modular System, the Emulator and Emulator II samplers, the Emax, the SP-12 and SP-1200 sampling drum machines, the Proteus sound modules and the Morpheus Z-Plane Synthesizer. The E-mu Modular System introduced several firsts, including the first digital polyphonic synthesizer keyboard and the first modular digital sequencer. The Emulator II helped establish sampling as a leading music technology of its era. Rossum also developed and licensed technology that enabled other classic synthesizers, including the Oberheim 4-Voice and the Sequential Circuits Prophet-5. His SSM music ICs appeared in instruments from Korg, Kawai and others.

The E-mu Modular System became an instrument of choice for recording studios, educational institutions and artists as diverse as Frank Zappa, Leon Russell and Hans Zimmer. The Emulator II became a fixture in professional studios worldwide and appears on innumerable hit records and film soundtracks. The SP-12 and SP-1200 sampling drum machines became defining tools of hip-hop and electronic production.

Rossum Electro-Music products are designed and manufactured in the United States.

Yes. Rossum modules are designed and manufactured in the United States and engineered for a long service life. Every Eurorack module in the line is 25 mm deep with keyed shrouded power headers and reverse-polarity protection. Wear parts are serviceable rather than disposable: OLED screens, knobs and front panels can all be replaced. Rossum also repairs modules beyond the two-year warranty period.

Rossum products are sold through authorized dealers worldwide and directly through the Rossum online shop. See the dealer list to find a retailer in your region.

Yes, five modules are offered with powder-coated black front panels: Assimil8or, Locutus, Morpheus, Panharmonium and Linnaeus. Silver panels continue to be produced alongside black. Replacement black panels are also sold separately for converting an existing silver module. Rossum publishes front panel replacement instructions (PDF) covering the swap.

All Rossum Electro-Music products carry a two year warranty against manufacturing defects, covering all parts and labor, from the date of original purchase. Normal wear is not covered. That specifically includes OLED display dimming, changes in potentiometer feel and slider wear. If you believe your module has a manufacturing defect, contact support with your serial number and a description of the problem.

The warranty is tied to the original purchase date, not to the owner. Rossum has no product registration system. There is no ownership paperwork to transfer. Rossum is committed to supporting all customers and works with second-hand owners on a case-by-case basis. If your used module has a problem, contact support with its serial number.

Yes, Rossum regularly repairs modules that are outside the two-year warranty. Contact support with your serial number and a description of the issue. The team will propose a repair path regardless of warranty status.

Contact Rossum support for an RMA number before shipping anything. Never ship a module without one. Use the support request form and include your serial number (on the rear of the module), your full mailing address with a phone number and a description of the issue. Ship the module only, with no cables or accessories, in the original packaging if possible, with the RMA number written on the outside of the box. For customers outside the USA, Rossum works with regional repair partners in Europe, the UK and Australia to reduce shipping time and customs complications.

Return and refund policies vary by dealer. Start with the dealer you purchased from. For orders placed directly through the Rossum online shop, see the shop's refund policy.

Use the support request form. Include your serial number (on the rear of the module), your current firmware version, a step-by-step description of how to reproduce the problem and any relevant photos or videos. For repair and order questions, also include your order number and shipping address. The more detail you provide, the faster the team can help.

Check your spam or junk folder first. Rossum's replies are known to land there. A reply lost to a spam filter is the most common cause of a "no response" report. Rossum is a small team and response times vary. If you still have not heard back, reply within your existing email thread rather than opening a new request and include your serial number, order number and a clear description of the issue.

All product manuals, quick start guides and supplementary documents are collected in the Documentation section of each product page, reachable from the support page. Each product's FAQ page also links its own manual and firmware directly.

Rossum publishes a range of supplementary documents alongside the owner's manuals. Depending on the module, these include replacement OLED kit installation instructions, knob alignment templates, front panel replacement instructions (PDF), a separated knob repair guide (PDF), a MIDI reference covering Assimil8or MIDI control through Locutus and firmware release notes. Everything is linked from the support page and the relevant product pages.

Yes, Rossum publishes front panel replacement instructions (PDF) covering how to swap the front panel on its Eurorack modules. A companion separated knob repair guide (PDF) covers reattaching a knob that has come away from its shaft. If you are unsure whether a repair is something to do yourself, contact support before starting.

Yes, factory presets and original card contents are available for the modules that ship with them. Contact support with the module name and serial number. For Assimil8or, the factory user card contents are also linked directly from the Assimil8or FAQ page.

No, OLED dimming is normal wear, not a defect. OLED screens have a limited lifespan and dim gradually with use. Running the display at maximum brightness, disabling the screensaver and leaving the case powered on for long periods all accelerate the process. Screen dimming is not covered under warranty. To extend screen life, enable the screensaver, reduce the brightness and power down your case when you are not using it. If a screen has become hard to read, Rossum sells replacement OLED kits that install without soldering.

Yes, OLED replacement is designed to be user-serviceable with no soldering. Rossum offers replacement OLED kits for Assimil8or, Morpheus, Control Forge and Panharmonium, available through the parts collection in the shop. Each kit includes the replacement screen and illustrated installation instructions. If you would rather not open your module, a local synth technician can fit a kit quickly.

Yes, in most cases. Potentiometer wear is normal over time and is not a manufacturing defect. A scratchy pot that makes audible noise when turned can often be improved with contact cleaner such as DeoxIT D5, applied carefully through the opening in the pot housing. If contact cleaner does not help, the pot may need replacement. Rossum can replace pots as part of a repair. Contact support with your serial number and a note of which controls are affected.

Yes. Rossum modules use 6 mm knurled-shaft pots and encoders. Standard knurled or D-shaft knobs from parts suppliers such as Thonk or Modular Addict fit them. Remove the original knobs by pulling straight up. They are friction-fit, not set-screwed. Pull evenly so you do not stress the pot shaft. Rossum cannot guarantee fit for every third-party knob. Standard 6 mm knurled-shaft knobs are widely compatible.

Press a fallen knob firmly back onto its shaft first. Knobs are friction-fit and usually reseat. If a knob will not stay on, Rossum's separated knob repair guide (PDF) covers reattaching it. If the shaft itself is loose or the pot or encoder feels physically damaged, the component may need to be resoldered or replaced. That is a straightforward repair. Contact support with your serial number and a description of the problem.

The procedure varies by module. Follow the steps on your product's FAQ page. Modules with a memory card slot, such as Assimil8or and the SP-1200, load firmware from the card. Most other digital modules, such as Control Forge, Satellite, Linnaeus, Mob of Emus and Panharmonium, load firmware by playing a WAV file into a CV input. Every product FAQ links its current firmware version as a direct download along with the exact update steps.

All firmware and documentation downloads are collected at the support page. Each product's FAQ page on this site also links its current firmware version as a direct download.

A failed update will not damage the module. If an update fails, retry it. Before starting, read the release notes and check your product's FAQ page for product-specific steps. Modules that load firmware from an audio file need the file played cleanly at line level without other audio interrupting the stream.

Eurorack is the most widely adopted modular synthesizer format. A Eurorack system is a case with a ±12V power supply holding rows of 3U-height modules, each performing one or more functions: oscillators, filters, samplers, envelopes, effects and more. Modules connect with 3.5 mm patch cables carrying audio and control voltages. You design the instrument's signal path yourself. The format was introduced by Doepfer in the 1990s and is now supported by hundreds of manufacturers, including Rossum Electro-Music.

HP (horizontal pitch) is the width unit for Eurorack panels. 1 HP is 5.08 mm. A module's HP width tells you how much horizontal row space it needs. Check it against the free HP in your case. Depth matters too: the module must be shallower than your case allows. All Rossum modules are 25 mm deep and fit shallow skiff-style cases like the Tiptop Mantis, Intellijel Palette and 4ms Pod series.

For reference, Rossum module widths are: Locutus 6 HP, Satellite 12 HP, Evolution, Linnaeus and Mob of Emus 16 HP, Morpheus 18 HP, Control Forge 22 HP, Panharmonium 26 HP, Assimil8or 28 HP and Triton 30 HP.

Yes, modules that follow standard Eurorack conventions patch freely across manufacturers. All Rossum modules follow these conventions: audio signals are ±5 V (10 V peak to peak), pitch control voltages use the 1V/octave standard where applicable and gate and trigger signals are standard 5 V.

Every Eurorack module lists its current draw on the +12V and -12V rails (and sometimes +5V) in milliamps. Add up the draw of all your modules on each rail and make sure your case's power supply provides more than each total, with headroom. Keep total draw at 80% or less of the supply's rated capacity to allow for power-on current spikes, especially from digital modules. Under-powering can cause freezes, noise or modules that fail to boot. ModularGrid calculates total consumption when you plan a system. All Rossum modules run on standard ±12V, need no +5V rail and are reverse-polarity protected. As an example, the Assimil8or draws 220 mA on +12V and 30 mA on -12V.

Power the case off before connecting or disconnecting anything. Connect the module's ribbon cable so the red stripe aligns with the -12V rail, which is usually marked on both the module and the case bus board. All Rossum modules use keyed shrouded power headers. The connector only inserts one way, which prevents a reverse-polarity connection. Double-check the orientation at the bus board end before powering on.

Control voltage (CV) is an analog electrical signal one module uses to control a parameter on another: pitch, filter cutoff, amplitude, timing and more. Patching a cable from a CV output (such as an LFO or envelope) to a CV input lets one module modulate another in real time. That routing is the essence of modular synthesis. Unlike a DAW, where you draw automation, in modular you route physical voltages and modules respond continuously to whatever voltage is present. Common conventions include 1V/octave for pitch, roughly 0-5 V or ±5 V for modulation and short pulses for triggers. A common beginner mistake is expecting DAW-style behavior from a CV input. A wrongly scaled or unpatched CV simply won't behave as you expect.

1V/Oct is the Eurorack pitch standard: raising a control voltage by one volt raises the pitch by one octave. Tracking can drift if the sending source is uncalibrated or if a receiving module's own calibration is off. Some spectral and filter modules also track certain settings better than others. Calibrate your V/Oct source first. If a module still tracks poorly across the board, that could point to a hardware problem. Contact support with the details.

A trigger is a very short pulse that means "start now", for example to fire a drum sound. A gate is a sustained high voltage whose length matters, for example holding a note open for as long as the gate stays high. A clock is a steady stream of pulses that sets tempo and timing. Modules specify which they expect on each input. For example, Control Forge advances on gate and logic rises but does not lock to a continuous clock.

Normalling is an internal connection from one jack to another that stays in place until you patch a cable in. Patching breaks the internal route. "True stereo with no normalling", as specified for Morpheus, means the left and right inputs are fully independent and the left signal is not automatically copied to the right. For a mono source into a module with no input normalling, patch the source to the input you want to use.

A VCA (voltage-controlled amplifier) controls level and dynamics. A VCF (voltage-controlled filter) shapes tone. An envelope generator produces a contour, such as attack-decay, to modulate a VCA or VCF over time. A raw oscillator or sampler often needs at least a VCA plus an envelope to produce a shaped, playable note rather than a constant drone. A VCF then sculpts the timbre. In the Rossum line, Evolution, Linnaeus and Morpheus are filters. Control Forge generates envelopes and far more complex contours.

Hardware samplers, including the Rossum Assimil8or, typically need integer PCM WAV files at a supported bit depth and sample rate. Floating-point WAVs use a different internal encoding that sampler hardware cannot read. They fail to load or produce errors. Most DAWs default to 32-bit float on export. That default is the most common cause of a sample that refuses to load. Convert to 16-bit or 24-bit integer WAV in your DAW or with a conversion tool. Also remove macOS hidden files (names starting with a dot, such as ._sample.wav) before using the card.

Format the card as FAT32. Rossum samplers such as the Assimil8or and SP-1200 do not read exFAT or NTFS. Insert and remove cards with the module powered off. Eject the card cleanly from your computer. Remove macOS hidden files (names starting with a dot) that can cause read errors.

A normal subtractive filter attenuates frequencies around a cutoff point you sweep. A resonator instead emphasizes specific resonant frequencies and can be "pinged" with a trigger to ring like a struck body. A Z-Plane filter, as implemented in the Rossum Morpheus, interpolates between complex stored frequency responses called cubes. It morphs between whole filter characters in ways a single cutoff and resonance pair cannot, which makes it a sound design tool rather than a basic tone control.

Spectral resynthesis analyzes incoming audio into its component frequencies in real time, then rebuilds or mutates that sound with a bank of oscillators. The Rossum Panharmonium resynthesizes its input through up to 33 oscillators. Because the analysis takes time, spectral tools have some inherent latency. They excel at turning any input into evolving harmonic textures, drones and pads.