Throughout the years, I’ve used this compressor more times than I can count - so much so, I had to purchase my own one for use in the real world rather than as a plugin.
Today, I’d like to discuss which revision is the ‘best’, why having a real one is a massive benefit to my recordings, and show how it can take an already good recording to a whole new level (especially if that recording has been done using our mics!).
Let’s dive in.
Revision A & A/B
The first of the bunch, the original and very rare Rev A isn’t only the ‘vibiest’ of the lot, but is also by far the most expensive and coveted because of its long standing history.
Urei and Universal Audio have continued to build around this one compressor. Also worth noting, it’s by far the noisiest of them all, - but what do you really expect given the technology, age, and sheer brutality of this unit?
Romantically known by many audio engineers to be called the Blue Stripe, or ‘Bluey’, this compressor was originally made in 1967 by Bill Putnam in an attic in Chicago with the intention of building a leveling amplifier for use in the studio.
This version doesn't house the same low noise design as the later revisions, but used FET’s rather than bipolar resistors which its later counterparts didn’t. Did I mention there were apparently only 25 of these units made as well? Making it just about as rare as it gets in today's audio world!
The revision A/B was basically the same but with a bypass on the gain reduction FET with some other very minor adjustments.
Revision C/D/E
The main differences in these designs was Low Noise circuitry added and amended from the original design. One of the main things to allow for this drop in shelf noise from the total harmonic distortion (THD) that compression naturally imparts on the signal passed through it was the lowering of voltage fed into the gain reduction FET and minor component changes.
For all intents and purposes the main changes from Rev C to Rev E were superficial, the biggest change being in Rev E which added the ability of 220v power to run the unit. Rev D is also now what Universal Audio currently base their design off of for modern made units, and according to many DIY builders, this version is the best to build yourself if you’d like to try to; and if not, my Klark Technic 1176 is well loved by many and is a great version of the Rev D at a lower cost and can be mod’ed to have a much more faithful recreation of the design.
Revision F/G & H
As I’m sure you can guess, these were made much quieter than the grandfather of the 1176, Rev A, by numerous changes to the circuit from version to version. Rev F notably largest change was the input transformer being changed from the Class A variant it once housed to a newer, much cleaner version, making it not only capable of much more output gain and with a slightly changed sonic signature (most prominent on the very top and bottom of the frequency ranges due to a change in model for the output transformer also), but also the lowest in THD across the variants and therefore the cleanest of the bunch in terms of sonic characteristics.
The largest change in Revision G was the use of the Integrated Circuit chip rather than the predisposed push/pull input preamplifier found in the previous revisions, or the op-amp integrated circuit found in Rev F; now, unless you’re into electronics, you’d be forgiven for not really understanding what this means, but a simple way to describe it would be it allowed a much quieter signal path and incorporated a much cleaner version of the 1176 - in fact, potentially the cleanest of them all in terms of not only noise, but THD as well.
Lastly, Rev H simply had some new colours but no actual internal changes - the off switch was made red, and the face plate was made a shiny total silver front plate, other than that the same overall sound and design as Rev G.
Why would you need or want a real one when there are many different versions of them as plugins?
The simple answer is dependent on whether or not you have a real love for analog gear or you’re happy in the digital domain. I know many engineers who love the sound of the faithful recreations found from companies such as the founders at Universal Audio, to my personal favourites at Arturia, which allows you to actually ‘age’ the unit in terms of how fast the compression can go - and I use them all the time as well, don’t get me wrong!
But having a hands on approach allows me to make a commitment to the recording process, mainly with vocals and bass guitar, which this unit is so widely renowned for being used for. The same could be said for a real Neve 1073 preamp, as opposed to a plugin, there's just something different in terms of not only quality but the signal once it’s ‘in the box’.
One day, plugin may well match up completely to the real thing, but for now, both hold their place in the world in my honest opinion and I’d encourage you to invest in a replica such as the aforementioned Klark Technic, or similar counterparts such as Warm Audio or Black Lion (who have an incredible version of the blue stripe as well). As always, I’d love to hear what you think, so feel free to discuss this on our social media pages, or email me at harri@jzmic.com
‘Til next time, stay creative!