UnderTone Audio UnFairchild 670M mkII – Vari-Mu Compressor Plugin

Most Fairchild plugins model the same thing: a 1950s variable-mu compressor, six fixed time constants, and all the limitations that came with it. The UnFairchild 670M mkII models something different – Eric Valentine’s actual rebuilt hardware, where the tube circuit follows Fairchild principles but the control set was redesigned for real work. Four continuously variable time constants join the six originals. The DC Threshold is user-adjustable. The detector switches between feed-back and feed-forward. Mid/side, sidechain processing and true bypass are built in.

Get it at PluginsVST for €59.99 instead of €149.00 – 60% off – with your own license key and a secure download link sent to your email.

Not a clone – a better machine

This distinction matters when you are shopping for “another Fairchild plugin.” Compared against other emulations, the UnFairchild does not sound like them, because the machine it emulates does not sound like a stock 670 either. The UTA-D plugin, developed in partnership with MixLand, captures that difference. Three software-only controls extend it further: makeup gain, wet/dry mix, and an overall THD adjustment – so you can separate distortion from compression, using the tube character without the gain reduction or vice versa.

What’s inside the box

• Faithful model of the UnFairchild 670M II hardware (not a stock 670 clone)
• Six original time constants plus four continuously variable ones
• User-adjustable DC Threshold for modern and vintage signal levels
• Feed-back / feed-forward detector switch, mid/side operation, sidechain, true bypass
• Software-only extras: makeup gain, wet/dry mix, THD adjustment
• VST3, AU and AAX on Mac & Windows

official UnderTone Audio website

The value case at 60% off

Hardware vari-mu compression is a five-figure conversation. Even among plugins, a properly rebuilt Fairchild with this control set is rare. At €59.99, the UnFairchild costs less than most single-purpose compressors while doing things none of them do – like dialing tube harmonics independently of compression. That wet/dry mix alone makes it a parallel-compression instrument, not just an insert. For mix engineers building a serious dynamics toolkit, this is the one that stays on the bus.

Tech specs at a glance

• Formats: VST3, AU, AAX (64-bit) – Mac & Windows
• Models the UnFairchild 670M II hardware by Eric Valentine / UnderTone Audio
• Mid/side, sidechain input, true bypass
• Internet needed for delivery and authorization

Why producers buy from PluginsVST

PluginsVST is built for producers who want pro tools at prices that make sense. You get hassle-free setup with clear installation steps, fast email delivery of your download link and license key, and friendly support if anything does not go smoothly. Deals like this 60% discount on the UnFairchild 670M mkII are exactly what the store is for – check the shop for more, or dig into the Mix & Master Plugins category for tools that finish your mix.

Frequently asked questions

What do I actually get when I buy the UnFairchild 670M mkII here?

The complete plugin, your own license key, and a download link sent to your email – the same full product, at 60% off.

How is this different from other Fairchild plugins?

It models Eric Valentine’s rebuilt UnFairchild hardware – with extra time constants, adjustable threshold and feed-forward detection – not a stock 670. It sounds and behaves differently.

Can I use the tube color without compressing?

Yes – the THD control and wet/dry mix let you dial in harmonic character independently of gain reduction.

Does it work in my DAW?

It runs as VST3, AU and AAX on Mac and Windows, so it loads in all major DAWs.

How fast is delivery?

Delivery is by email and typically arrives within minutes of checkout.

A Fairchild, rebuilt by someone who actually uses one. At 60% off, it belongs on your mix bus.