written by
Bojan Šernek

Fairchild 670 V2.0 Released on mix:analog

Gear 3 min read

One of the most interesting and iconic pieces on mix:analog is our very own interpretation of the legendary vari-mu compressor/limiter Fairchild 670. Dubbed as the "king of compressors" and "the best compressor in existence" by some experts, it is certainly one of the most sought out and used among vari-mu types.

Using it on mix:analog means you can rent out a hardware unit for a small fee. You can change the controls on the screen with a click of the mouse, while real-time lossless audio streams to your speakers so you can make the best decisions. When you have bounced your tracks, another user can take over.

fairchild 670 vintage king
Vintage King Fairchild 670

The story of mix:analog Fairchild 670 so far

Our team has completed the Fairchild 670 a few years ago and it has seen years of offline use. On mixes, vocals and drum groups for Laibach releases for example. After we drafted it for mix:analog, we added analog automation to the compressor and put it online. It was used mostly for mastering as one of the components in our vintage-inspired RACK1.

However, its colour was a bit too much for everyone, so it was replaced by the more general GoldCan VCA.

To refresh your memory, check out the tutorial and find out what it's all about.

In its new life as an independent product, the Fairchild 670 has seen a lot of use. Producers use it when looking for a more vintage, slower-paced sound that still has a lot of snap and life. We heard a lot of people praising it for Blues, Acoustic, Jazz and vintage R&B.

Fairchild evolution does not stop here.

We have just released another update of the Fairchild 670. We wanted to address a few issues and make it an even better product. One that could be used on more material than slow, vintage pieces. So if you previously tried it and did not really like it because it was too much colour or too slow - you should try it again. It's really worth it.

So what did we do?

  • Sped up the metering significantly and now the meters react as fast as on the GoldCan and the G24
  • Made the input gain and ratio knobs work in a "logarithmic" way to extend the usable range
  • Checked the timing constant wiring against photos of a real vintage Fairchild 670 and corrected a mistake
  • Recalibrated all of the tubes, the power supply and all internal voltages

Cool. What's the benefit for me?

Updated metering makes it easier to gauge the compression effect and timing visually and give you a sense of how much the compressor is working. You will be able to dial in a sound faster and the results will be more consistent across different sessions.

Logarithmic knobs mean that turning the knob and finding a sweet spot before could be a bit challenging. Twisting the knob could mean very little change in the way the compressor reacted. Or sometimes some small adjustments seemed to make big changes. With this update, the feeling should be more even and smooth across the range of the knob.

The timing constant bug only impacted the first (fastest) setting. It seems that the difference between the first two timing constants was minimal before while it should be actually quite obvious. There are many schematics on the web that don't entirely line up with each other on this crucial part of the Fairchild 670. We found some photos of the original insides and modified the circuit to suit.

Now the difference is there! And it changes the Fairchild 670 usability significantly. Before the upgrade, it was always a little "slow". Now you can dial in a very aggressive, fast sound on the first time constant setting.

fairchild 670 insides
Fairchild 670 Insides

Will you raise the price because of this?

No, we will not raise the price of the Fairchild 670! We take every opportunity to take care of and improve our analog gear, but we see it as a part of the general maintenace that we do instead of you - so that's already included in the price!

The current price of using the Fairchild 670 compressor online is 105 mix:analog tokens (MAT) per 15 minutes, which translates to roughly 5$. Try it on mixanalog.com, it's really worth it.

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fairchild 670 vari-mu compressor