FREE Access Virus C Synthesizer Emulation By DSP5630 (But There’s A Catch!)


DSP56300 Emulation Blog brings you the sound of the iconic Access Virus C (and more) for free.

The Access Virus C first appeared in the early 2000s, and, like many vintage synths, it’s perhaps more sought-after now than it was early on.

The synth became a favorite of many musicians creating any kind of industrial or dystopian sound. Trent Reznor of Nine Inch Nails, who went on to score numerous films, TV shows, and video games, was a fan of the Access Virus C.

These days, you might be able to find a few hardware units for sale, some well under £1000 but not typically in great physical condition.

As a free alternative, we have the DSP56300 Emulation Blog, which perhaps offers the purest form of emulation available.

The team behind the website is a group of people dedicated to reverse-engineering and emulating the DSP56300 series of processors.

While we’re talking primarily about the Access Virus C here, these Motorola processors powered many classic synths from the 90s onwards, like the Nord Lead 3, Novation Supernova, and Waldorf Q.

After listening to some demos, the emulation sounds pretty incredible at times. The reason the emulation sounds so pure is that you have to feed it with the ROM file from the original hardware, which you’ll have to acquire by yourself, and it’s at this point the waters get a little muddy.

To keep things incredibly simple, for my own sake, rather than yours, we have an original ROM file running the original code, and a reverse-engineered DSP, meaning we should get the real thing in some ways.

The developers provide a test program to ensure your system is capable of running the emulator. The website also includes install/setup instructions since there are a few additional steps concerning the ROM file.

If we see and hear the end result, it’s pretty impressive. The emulation sounds incredible, as I said, especially the grittiest sounds that create an almost uncomfortable feeling. The interface looks good, too, it’s not overly modern, which stays true to the original hardware, and it seems easy to use.

BUT, before you get to all that good stuff, you have the issue of acquiring the ROM file, which technically might be a simple process, but it does raise some legality concerns.

Check out Wave Manuel 2.0 for some more free synth goodness.

The DSP56300 Emulator is available in AU, VST2, VST3, and CLAP formats for macOS, Windows, and Linux.

Download: Osirus DSP56300 Emulator


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James is a musician and writer from Scotland. An avid synth fan, sound designer, and coffee drinker. Sometimes found wandering around Europe with an MPC in hand.


    • Dude, Seriously. I’m trying to do this, but it’s not that simple. I found the website you put here, but there are so many options. I tried the Korg Polysix file, as suggested in the forum, but I’m not having results on my DAW (Ableton). I place the .bin file in the same folder as the vst but the DAW is not reading. Could u help me?

      • That emulator will currently only work with roms from the Access Virus B, or C models.
        And the Korg Polysix will never be cover by that project because the hardware is too different, in so many ways.

  1. Google ‘virus c am29f040b_6v6’, put this .BIN of the virus c ROM and the emulator into your VST folder and you are good to go. If vst3 does not work, try vst2 instead.

    Some of the presets sounds incredible!

    Article says it is a ‘grey zone… Well i think, not really. Think twice before using this synth for commercial stuff: The ROM usage, even if reverse engineered, is only fully legit if you own the corresponding hardware from Kemper GmbH. Don’t think they will sue, but why take a risk when there are so many excellenct low cost or free synths out there?

    • Read into it, Christoph Kemper is aware of the project.

      Here is what the devs are saying and why the are not emulating virus ti / ti2:

      “However, currently we do not have plans to release a version of the emulator that supports the Virus TI, TI2 or Snow as this generation of synthesizers is still being sold. We do not want to negatively impact current or future sales of Kemper GmbH or affiliates, it is exactly the opposite. We appreciate the achievements of Access Music / Kemper and created Virus B & C emulators as an appreciation and to preserve these great synthesizers in a digital form.”

      I am not a lawyer, but up to this point is seems sort of okayish to use this in connection with the virus c. So okay, i reword my summary from the first post, it IS a grey area – unless, of course, you are talking to an IP specialized lawyer, who will tell you, how much of a IP case this is :)

      Any other opinions on this?

  2. I tried this a year ago or so, and the ROMs were easy to find. But my system is not strong enough for it.
    Concerning the “grey zone”, IMO Access missed the opportunity to do this themselves. They still can do it, which I hope.they do. Korg has had success turning their millennial synths into VSTs now.

    • Adam Szabo’s Viper VST instrument is a good Access Virus imitation. And it sounds fantastic.
      The things is, it costs 90 USD and for WIDNOWS only.

      • And while Osirus is a Virus B & C emulator, Viper goes further being a Virus TI simulator, being even preset compatible. A veritable tour-de-force. Windows-only because made with Flowstone.

    • A limitation from the OS of the original hardware and its glorious 2 lines of LCD text… :D
      The preset manager has categories support for the soundbanks that support them.

      • On the original skin, I never clicked on the presets button.
        I would always select through the left side that listed huge banks, but no categories.
        I just figured this out today. I’m such an idiot.
        Everything is categorized beautifully now. Still learning.

      • For better performance use c rom 6.5, not 6.6….
        6.6 was a beta, still discontinued, attempt to bugfix, but this not fixed, only more problems appeared. And according to tests, 6.5 is better (performance, faster calculations, less bugs). Also virus classic rom and b rom give more performance, but less features, polyphony and some difference in presets due to filters etc (try Bypass preset from vengeance packs).
        All presets sounds same as my hardware.
        It uses same native unusual sample rate as Virus hardware does (46875 as remember correctly), so plugin goes with built-in sample rate conversion to DAW project sample rate. It is not good, so 44100 sounds worse, dirtier at highs (noticeable on low sines), a lot of aliasing due to conversion. So 48000 and up are waaaay better.
        Waldorf mQ is next as I understand. No modern synths because they are on market, only old discontinued.

    • You can take the chip out of the PCB, not sure if it’s soldered or on a socket, and use an EEPROM programmer connected via serial/USB to read (dump) the contents of it.
      Be aware that unsoldering a chip is not without risk of damaging it or the PCB (what’s called ‘lifting a trace’).
      I don’t think there is a way to extract the content by MIDI as SysEx, and even then it wouldn’t be what’s needed.

    • Never mind. Found it. Different from the image of this article that has a browser section, I found the presets on the left (red) side of the plugin.

  3. The new version of the emulator 1.2.29 no longer requires a ROM binaries and you can use midi files from OS Update available on the Access website.
    Latest Change Log:

    1.2.29 (2023.02.13)
    * DSP performance improvements 15%-20%
    * Osirus can now boot from OS update .mid files. ROM binaries are no longer required if a pair of “first….mid“ and “…second…1024.mid “ files are found next to the plugin. The second file is optional. If Osirus is booted with the first file only, no ROM presets are available
    * Patch Browser can now load presets from .vstpreset, .fxb and .fxp files, including those saved by the Access Virus TI Control Center and the Access Virus PowerCore
    * File names of plugins have been modified to include Osirus in its name

    * Fix plugin state not correctly restored if a Virus B ROM is used
    * Fix swapped left/right channels and phase issues
    * Fix UI didn’t update play mode correctly in some circumstances when loading a .vstpreset / .fxb / .fxp
    * DSP thread now runs at higher priority (Mac/Linux)

    • Using the update files instead of a ROM dump is a nice move.

      Unfortunately this new version fails to validate in Logic Pro on Monterey (latest versions). Hopefully they can fix this soon.

      • Maybe this information will help:

        @Mac @Logic Pro For those of you having validation issues with the 1.2.29 builds and have run the commands to deal with the signing issues, did you modify those commands to reference your actual environment?

        Please note that the name of the plugin files themselves have changed with 1.2.29 (from “DSP56300Emu” to “Osirus”) and you will need to modify those -xattr commands to reference the actual path and filename of the plugin files you want to “fix” and allow as unsigned plugins to validate. Use the examples below (filling in the blanks of the plugin names and correct paths if yours are different):

        1.2.25 and prior:

        sudo xattr -cr /Library/Audio/Plug-Ins/VST3/DSP56300Emu.vst3

        sudo xattr -cr /Library/Audio/Plug-Ins/VST/DSP56300Emu.vst

        sudo xattr -cr /Library/Audio/Plug-Ins/Components/DSP56300Emu.component

        sudo xattr -cr /Library/Audio/Plug-Ins/CLAP/DSP56300Emu.clap

        1.2.29 and future:

        sudo xattr -cr /Library/Audio/Plug-Ins/VST3/Osirus.vst3

        sudo xattr -cr /Library/Audio/Plug-Ins/VST/Osirus.vst

        sudo xattr -cr /Library/Audio/Plug-Ins/Components/Osirus.component

        sudo xattr -cr /Library/Audio/Plug-Ins/CLAP/Osirus.clap

        • It’s not a quarantine issue. I ran xattr -cr to clear any extended attributes from the component files (I’m using the FX version as well) but they still fail to validate.

          Logic takes significantly longer to launch as it tries to scan the Osirus component files. Then it stalls again when adding a new track.

          Everything works fine once I roll back to 1.2.25.

  4. Now that’s a great one! VST3 working great with Access Virus C (am29f040b_6v6).zip ROM from, Ableton 11 on Mojave

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