UnderTone Audio – UnFairchild 670M mkII v1.0.4 VST3 AU AAX WIN MAC

This plugin is a painstaking effort to recreate the long-awaited
Unfairchild 670M Mkii Vari-Mu audio compressor with improved sound.

Developed in collaboration with MIXLAND and Eric Valentine, the project involves a process
that begins with testing and measurements, then listening and experimenting, followed by iterative tweaks
and refinements over a period of over six months. The result is a plugin that undoubtedly
captures the unique atmosphere and character of the equipment.

Now we can all enjoy the magic of Unfairchild’s classic sound in plugin form.

The UnFairchild 670M II module’s features and controls are the same as the hardware, with a few additions.
We’ve added a power level control, wet/dry mix control, and a master THD control.
A Total Harmonic Distortion control allows you to increase
or decrease the amount of distortion in the UnFairchild style.

It’s possible
Test how closely the plugin matches your hardware with this amazing drum compression system!

Mix Bus Magic:
Compression on your mix bus can make or break your mix.
Experience the richness, energy, and width the UnFairchild 670M mkII plugin can add to your mix.
This plugin is a “Mix Maker”!

Even the greatest singers need great compression.
Listen to how this vocal performance goes from “impossible balance” to “easy delivery.”

Version 1.0.4 [11/06/2025]

  • Fixed a bug where the gain reduction meter would behave incorrectly
  • Fixed a bug where the scroll wheel would not work when l+r was connected
  • Added a clean gain control to the top panel
  • Added a relative reference for the I/O controls in the top panel

Version 1.0.3 [10/29/2025]

  • Optimized CPU usage.
  • Reduced plug-in load times.
  • Added support for Pro Tools key commands/shortcuts.
  • Added Pro Tools automation highlight indicators.
  • Fixed bypass level behavior in the BYP control.
  • Fixed a Pro Tools bug where reloading a session could restore inconsistent bound values ​​on some systems.

Version 1.0.2 [09/30/2024]

  • Added SC HPF
  • Added plugin update notification
  • Added ext sc switch to A/B mode
  • Fixed audio volume increase when moving knob quickly
  • Changed output gain to wet path
  • Changed external sc from feedback to direct (fixed external sc transients)
  • Removed visual adjustment areas
  • Reduced loading time

Version 1.0.1 [09/16/2024]

  • Fixed resampling in Cubase
  • Added menu items as automated parameters

Version 1.0.0 [09/16/2024]

  • Initial release