The History of The RS124 Compressor - From Creation, Rediscovery & Plugin

Few pieces of gear define music history as the RS124 does. The custom-built RS124 compressors were the secret weapon of Abbey Road engineers during the '60s, hand-built by Abbey Road/EMI technical legends Bill Livy, Len Page and Mike Bachelor. The story behind them, however, is an interesting one. Our Head of Audio Products, Mirek Stiles, explains the history behind the “holy grail of smooth compressors”, the rediscovery at the start of the millennium and how it's now been replicated as an audio plugin with Waves Audio.


The History Behind The RS124 Compressor

Last week we released a plugin of the fabulous RS124 compressor, with our equally fabulous plugin partners Waves Audio. Working on this project brought back a lot of personal memories for me. I witnessed the rediscovery of these all valve beauties in the early 2000s when I was still relatively new to the studio world and have since seen them used on numerous sessions on a variety of sources. The RS124 rarely disappoints and most user’s kind of fall for it in a big way. It’s like sonic glue.

In my personal opinion, I’m yet to come up against any compressor that can compete with the character the RS124 produces – I can see why it was referred to as the Abbey Road engineers' secret weapon and used on pretty much every pop recording made at Abbey Road during the 1960s. Only a handful of these beautiful beasts were ever produced and unlike the REDD or TG recording gear of the same era, they didn’t really make their way to many of the other EMI studios around the world, the exception being one in France and another in Argentina. It’s fair to say, these highly modified Altec compressors were very rare indeed.
While we are on the subject of modification, it’s worth delving a little deeper into the sometimes misunderstood history of how these units came to be. Following a recommendation from EMI sister studio Capitol in LA, Abbey Road imported a few Altec compressors for use in the studios in 1959. As was the norm back then, the technical team gave the freshly imported units a thorough going over and decided they didn’t really like what they were seeing from the American compression unit, both inside and out, and went about pretty much re-designing it from the ground up. In fact, the only recognisable feature from the original unit was the Altec badged VU meter on the front panel. By the time the technical boffins had finished with the unit, it was a very different kettle of fish altogether. The units then found their way into the studios and cutting rooms and proved to be rather popular. In fact, I think it’s safe to say these little beauties can be credited with playing a major role in defining the sound of Abbey Road during the ‘60s period. Due to the constant tinkering by the chaps in white lab coats, namely technical legends like Len Page, Bill Livy and Mike Batchelor, no RS124 really sounded the same. Each serial number had a different attack or release time; some were more aggressive and became tracking favourites whilst other more gentle examples were better suited for buss compression and cutting room duties. The RS124 is a unique, rare and beautiful thing, and I have often heard engineers referring to its sweet, dulcet tones as “creamy” – there is nothing else quite like the RS124 full stop.
Front - Bill Livy and Mike Bachelor. Rear - Francis Thompson, Chris Buchanan and Len Page. In the Abbey Road LAB circa 1974

Front - Bill Livy and Mike Bachelor. Rear - Francis Thompson, Chris Buchanan and Len Page. In the Abbey Road LAB circa 1974


The Rediscovery of The RS124

It was the year 2002 in the control room of Studio Two at Abbey Road when I first heard the distinctive and downright exciting magic of the RS124 compressor. I was assisting the mighty talented producer Jon Brion for an album by the similarly brilliant Fiona Apple when I was first introduced to the aggressive and beautiful sound of the shamelessly heavily modified Altec 436B compressor.
After the exhausting and, at the time I thought, rather excessive request to personally audition every single valve microphone in the building, Jon asked me if we had any RS124s. At this time, I didn’t know what he was talking about. To be fair, the mystic curtain of the RS124 was only publicly lifted once the fantastic Recording the Beatles book was published, but as both authors for the said book were currently standing with me in Studio Two’s control room and the book hadn’t yet been written, I can forgive myself for not having a clue what Jon was going on about. My first thought was to ask technical engineer Lester Smith as, if anyone would know what this elusive RS124 business was all about, he would be the guy.
I introduced Jon to Lester, along with Brian Kehew and Kevin Ryan (authors of Recording the Beatles) and they all hit it off like the Fab Four themselves. Lester said something reassuring like “leave it with me” and a few hours later, he delivered a single RS124, serial number 60070B, to the control room for a test drive. It turns out Lester had at least three (perhaps more) of these units hidden in one of his many deep cupboards, rescued decades earlier from an almost guaranteed skipping. This might sound crazy, but during the 1980s that gear was seen as old hat and of no further use. Luckily Lester didn’t agree with this philosophy and in some cases actively rescued equipment that might otherwise have been condemned to eternal damnation.

Lester was quite rightly very proud of himself for not only having the foresight to keep these beautiful units under safe lock and key, but also for getting one of the tricky little blighters up and running. He announced to the room it might be a little on the noisy side, but it was in full working order. Without any hesitation, I was quickly instructed to patch in the unit and insert it over the bass guitar channel. Jon (or someone) then proceeded to play said bass guitar and the look on everyone’s faces in the room was of total astonishment. Jon simply said “that is it – that is the sound”. Jon was of course referring to the sound of Paul McCartney’s bass guitar; the sound that has been forever immortalised on some, let’s be honest here, pretty famous ‘60s recordings conducted in the very same room we were all standing in.

It was a memorable session for sure. Lester managed to get three RS124 units fully operational, Kevin and Brian wrote a fabulous book, Fiona Apple had her brilliant songs temporarily delayed by about three years (look it up on Wiki) and I learnt about the Abbey Road engineers’ secret weapon of the 1960s - the RS124. I also walked away with a Jon Brion evaluated and approved list of Abbey Road valve microphone serial numbers – handy information to have in your back pocket.
Pictured: Brian Kehew (left) Norman Smith (centre) & Kevin Ryan (right)

Pictured: Brian Kehew (left) Norman Smith (centre) & Kevin Ryan (right)


The Abbey Road / Waves Audio RS124 Audio Plugin

I’m so happy we can finally release this magical sound to the next generation of engineers and producers with our good friends at Waves. There are many flavours to discover in this plug-in and one thing I can guarantee is you are going to have fun. You will be chasing the ghosts of studio legends as you sculpt and define your sound with these rich sounding gems. Be warned, the vibe from the meticulously modelled RS124 is addictive – enjoy the journey.
Mirek Stiles – Head of Audio Products, Abbey Road Studios, September 2020