J Rockett unleashes its Airchild SixSixty sonic interpretation of the legendary 1960's Fairchild 660 Tube Limiter / Compressor

For some reason I didn’t get a press release for this one - which is unusual for J Rockett, as I’ve collaborated quite closely with that brand of late - it turns out my main connection Zac was not overseeing this release - and hence I got overlooked! And while in the other release materials, and in the manual in particular - much is made of the legacy of that most favoured 60’s studio compressor inspiration, there is no proper mention of how J Rockett managed to replicate such a complex circuit in so small an enclosure. Obviously an Integrated Circuits / Opamp take on the Tube format - which was incredibly complex in its nature. And of course the J Rockett variant is more of sonic recreation / sound-alike.

The original 1960’s Fairchild 660 Single Channel Tube Limiter / Compressor, of which only around 1,000 units were made, was comprised of no less than 12 x RCA 6386 Tubes and multiple hand-wound transformers - with a gain boost of around 8dB. The Dual Channel / Stereo 670 Model was even more extreme with 20 of those RCA 6386 tubes, 11 hand-wound transformers and 2 inductors. It also weighed a tonne at nearly 30kg! While regardless of those weighty stats - these were very much the favourite studio compressors of the 60s and 70’s - where Abbey Road Studios had 8 or 10 of them, and Capital Studios also deployed a significant number of the same.

There’s much in the various accompanying texts that describes the clarity of the 2-1 Compression Ratio, and 30-1 Limiting Ratio of the original - while it was best known for adding a certain harmonic texture / sonic richness / or ’growl’ even to the output. And certainly had not nearly the same degree of transparency as the later optical compressors. The 660 / 670 rather added some very recognisable colour and signature tone-enhancing qualities to the signal.

The original 660 units nowadays go for more than $20,000 a piece - and the 670’s are considerably more! There is a 660 currently on Sweetwater for $25,000.

So recreating those signature harmonic shades of the original would surely make for some significant challenges - and it would be interesting to see a studio comparison between new and old at some stage across the full sweep of those devices.

Controls - Output (Level), Tone (Tilt EQ), Blend (Parallel Dry Blend), Threshold (Compression Ratio / Degree).

With Blend and Threshold dialled all the way back - the Airchild makes for a very expressive harmonic boost. Alas there are no proper stats quoted in the literature as to dB gain range or how close the Compression / Limiting range is to the original.

To introduce the harmonic enhancement elements into a compact format (without all those tube stages) I would imagine would need some smart use of specially selected clipping diodes and cascaded opamps within the circuit, but as mentioned - none of the literature really lays out how J Rockett went about fully replicating that 12 tube stage and multiple transformer tone-enrichment. It does not state even as to whether there is some sort of audiophile transformer onboard - but which J Rocket have deployed before in some of their circuit designs. I well understand the need for some degree of secrecy to preserve the competitive advantage. But I would have loved a few insights into the process of sonic replication.

The big question here really is how close does this Airchild SixSixty pedal come to fully recreating that Fairchild 660 magic, and if it’s even fully possible to accurately recreate such an expansive and complex circuit in such a compact format. I really would have loved to have had more insights on the development and engineering of the pedal.

However close the Airchild SixSixty comes to sonically replicating the original - there’s no question that it’s exceptional value for money - coming in at just $229 - available quite widely now, and including on Sweetwater.

I’m actually very happy to see another unique compressor pedal on the market - where many said that it wasn’t practically possible to recreate the 660 in such a small enclosure. The Compressor Pedal landscape has never been broader - and there are so many superior representatives of that genre now - with several innovations happening in just the last couple of years.

I personally am still firmly wedded to my JA Bloom - in part because of its control and use-case topology - and also because of its very granular 3-in-1 nature - where I use every facet of that features set all of the time.

It’s for sure nice to see a pedal representative of the Fairchild 660 at last - and I’m sure the debate will range long and hard as to how meritous this particular execution is. I’ve long been a fan of J Rockett - and Jay for sure has a wonderful ear for tone!

And I love those Marconi / Neve-style knobs. Looking like a very worthy execution of a challenging circuit. And I would of course love to hear your own opinions here too! In any case - I love that we pedal fans now have the option of a Fairchild 660 style / sounding compressor. Will be interesting to see if anyone else takes up the challenge!