VProm

VProm was first released in 2014 as a groundbreaking software plugin that faithfully emulated the internal circuitry and filtering of one of the most iconic drum machines of the early '80s; the LM-1. This legendary device revolutionized music production by being the first to incorporate real drum samples, setting a new industry standard and shaping the sound of an era...

Welcome to the next chapter - VProm 3

Over the years, VProm has become a staple in music production, celebrated for its accurate variable sample rate emulation of classic DACs and its ability to load swappable EPROM samples. Now, with the release of VPROM 3.0, I am taking things to the next level. This major upgrade enhances both features and usability. While previous versions excelled at replicating EPROM-based drum machines, primarily the LM-1, Version 3.0 expands its capabilities even further.

Concept

VProm offers an experience closest to the original hardware, as it does not rely on samples or typical sample-based reading. Instead, it precisely models clocks and counters that read EPROM memory, feeding the AM6070 DACs to decode EPROM data in real-time. The system emulates the CEM 3320 filters, with adjustable control over CV pulse shapes, allowing you to control the amount of transient that passes through unfiltered or completely bypass them. The special hi-hat circuitry and VCA generate unique hi-hat sounds on each trigger, with decay control for added versatility.

Each voice is individually tunable, with a wider range from the outset, without requiring electronic tweaks. VProm also features separate outputs for your DAW and handles velocity for enhanced expressiveness. You'll maintain that authentic raw sound on every tune, with true variable sample rates. Additionally, all voices can be replaced with external EPROM data, just like on the original hardware, unlocking an entirely new range of sounds—all while still being processed by the circuitry.

VProm Main Features:

• Faithful Hardware Emulation – The closest software recreation of the legendary 80s drum machine, with real-time DAC and EPROM sound processing.
• New Mac & Apple Silicon Support – Native VST3 & AU support for both Intel & M1/M2 Macs with Universal 2 compatibility.
• Built-in WAV Resampler & EPROM Burner – Convert and preview samples, then burn them into authentic 8-bit EPROM images.
• Real-Time µLaw DAC Curve Control – Modify decompression ratios for unique transient shaping and distortion effects.
• Enhanced Mixer with Multi-Output Routing – Choose between Single Mix, Multi Post-Mixer, or Multi Pre-Mixer for flexible DAW integration.
• Expanded Voice Card Features – New DMX-based controls, CEM filters, and optional VCA envelopes for deeper sound sculpting.
• New 48 PPQN Internal Clock & Clock Drift – Accurately recreates vintage groove timing with adjustable humanized drift.
• Revamped GUI & Skins – LM1, DMX, and Linndrum skins with vector graphics, DPI scaling, and HD visuals.
• Amazing New EPROM Management Panel – View all 14 custom EPROMs in one window with waveform visualization, an internal EPROM library browser.
• Advanced EPROM Playback Controls – Adjust start, loop modes, and memory playback in real time.
• New "EPROM Kit" Format – Save and recall full custom EPROM drum sets separately from plugin presets.
• New Drum Voice: "Ext2" – Expanding the kit to 14 sounds.
• Enhanced Oversampling – New "X16 ALL" mode for full high-frequency processing.
• Backward Compatible with VPROM v2.0 – Load existing presets, including custom EPROMs, directly in VPROM 3.0.
• No Fake Samples – 100% Authentic – No EQ, no FX, just pure raw drum machine sounds.

VProm version 3.0 change-log

• New Mac VST3 & AU Support – Now fully compatible with Apple Silicon (M1/M2+), offering native performance. Built as a "Universal 2" plugin, meaning both VST3 and AU work seamlessly on Intel x86-64 and ARM64 Macs.
• Built-in WAV Resampler & EPROM Burner – Convert, preview, and load samples effortlessly.
  Import any WAV file and resample it (or keep it as-is) at ~27kHz with input stage emulation and µLaw 8-bit compression—just like the original hardware. Generates fully compatible .bin EPROM images.
• Custom EPROM Manager – Advanced visualization, file handling, internal browser, and improved organization for easier workflow.
• Real-Time µLaw DAC Curve Response Control – Fine-tune how your samples are decompressed for precise sound shaping.
  The AM6070 DAC chips used a built-in µLaw transfer function to decode and replay sound data. Now, you can subtly match real-world DAC chip variations—or push the transfer function further for creative sound design. This feature acts like a hybrid transient designer & distortion unit when dialed in aggressively.
• Enhanced Mixer – Greater flexibility with multi-output routing and improved equal-power panning.
  Choose from three routing modes:
  Single - Main Mix: All voices are processed through the internal mixer (with volume, pan, etc.) and sent to the **Main Stereo Output**. Dedicated outputs are disabled.
  Multi Post-Mixer: All voices still pass through the internal mixer, but instead of going to the Main Stereo Output, they are routed to their own dedicated stereo outputs. The Main Stereo Output is disabled in this mode.
  - Multi Pre-Mixer: A hybrid mode where voices are sent **both** to the Main Stereo Output (post-mixer) and their dedicated outputs (pre-mixer, direct signal). This allows external processing while keeping a full internal mix or a quick sub mix.
• Revamped GUI & Skins – New LM1, DMX, and Linndrum skins with HD graphics, vector knobs, full EPROM Kit View, and an enhanced CEM filters view. GUI now adapts to different DPI sizes for sharper visuals and UI scaling.
• New 48 PPQN Internal Clock – Recreates the subtle groove and timing feel of vintage drum machines.
  Unlike modern clocks (~960 PPQN), this emulation locks trigger events to a true vintage-style clock pulse synced to your DAW. The effect is subtle but noticeable, especially on swung or loose beats.
• Real-Time Clock Drift – Adds organic, human-like timing imperfections.
  Recreates the natural clock drift found in vintage drum machines, where internal clocks were never perfectly stable. Unlike the subtle effect of the 48 PPQN clock, this feature introduces a more noticeable, organic timing shift, mimicking the imperfections of classic hardware. With a tweakable drift range from 1ms to 40ms, you can achieve anything from a realistic analog-style drift to a more exaggerated laid-back groove, similar to a drummer playing with extreme looseness and feel.
• Expanded Voice Card Features – New DMX-based controls for Bass, Congas, Toms, Ext1, and Ext2.
  CEM filters now offer full control over envelope response and decay, along with newly introduced VCA settings. "Expert Mode" unlocks advanced sound tweaking, while "Legacy Mode" preserves the simpler v2.0 pulse control. The optional VCA envelope introduced in VPROM 3.0 is crucial for accurately reproducing certain DMX sounds, especially the Bass Drum.
• Advanced EPROM Playback Controls – Real-time control over EPROM reading, including sample start, length, and loop modes.
  You might be familiar with the LM1 hi-hat, which constantly loops and is shaped by a VCA. In VPROM 3.0, this behavior can now be applied to other voices. You can also modify loop behavior to either start in sync with triggers or run continuously, even for the hi-hat. By setting a short length (around 123 samples) and moving the start point, you can achieve a wavetable-like effect. While start and length modulation is possible, it does not operate at audio rate.
• New Drum Voice: "Ext2" – Expands the total drum kit to 14 sounds.
• New Master Controls – Master tuning & volume knobs for greater global control.
• New Velocity Mode: "Original 2" – An alternative to the classic "Original" mode with a different approach to velocity handling.
  Similar to the "Original" mode, where velocity determines whether a sound plays at full or half volume. However, in "Original 2," the volume change is controlled by the trigger number itself. Each trigger has two assigned MIDI notes—one plays at full volume, and the other at half volume.
• Enhanced Oversampling – New "X16 ALL" mode processes all 14 EPROM outputs at 16x oversampling.
  Previously, only high-frequency voices were processed at X16, but now all voices can benefit from this setting for greater flexibility when using custom EPROM.
• Compatibility with VPROM v2.0 Presets – Load your existing .fxb presets, including ones with custom EPROMs, directly into VPROM 3.0.
• New "EPROM Kit" Format – A new way to save and recall full drum kits independently of plugin presets.
  A .VpromKit file allows you to store and reload a complete custom EPROM drum set without saving a full plugin preset. This lightweight format only stores EPROM file paths and their assignation, CEM config and hihat loop state, no other settings are saved, making it easy to organize and reuse drum kits across projects without changing your current tuning or mix.
• Additional Sound Tweaks – Fine-tune open hi-hat decay and enable dynamic hi-hat tuning. Dynamic tuning is also available for Toms, Congas, Ext1 & Ext2.
• Bug Fixes – The infamous VST3 bug is now gone, no more reset or crashes.
• Removed: VST2 & 32-bit Support – VPROM 3.0 is now **64-bit only** (VST3/AU).
• Does NOT Replace VPROM v2.0 – VPROM 3.0 installs alongside v2.0 with its own plugin ID, ensuring backward compatibility with existing projects.