Many of us use Universal Audio 1176 compressors for a variety of applications in our daily workflow. We like how they sound! It turns out however that in the past 54 years there have been many revisions to the unit. Many of these have been emulated and released as plugins by UAD, much to our benefit.

Let’s take a look at the history of these revisions and try to understand the motivation behind them. Later, I’ll share observations of the 1176 compressor plugins and include some audio examples so you can draw your own conclusions.

How do the various UAD 1176 compressor models perform against each other?

An 1176 Timeline

In 1966 Bill Putnam’s Universal Audio featured tube compressor models 175 and 176, but in the lab plans to build a solid state compressor utilizing a circuitry based around a FET (Field Emitting Transistor) in the sensor circuitry of the unit were moving along.

In 1967 the 1176 Rev A was introduced to the market. It featured a silver faceplate with a blue stripe, which is a marked difference from the black plated model we think of. The Rev A also featured a sleeker look with smaller knobs and more of them:  TIP: By shutting off the attack, the unit actually functions as a line amp with 45 dB of gain!

Although the 1176 Rev A is a feedback-style compressor (read up here; Feedback Vs. Feed-Forward Compression: The Differences You Need to Know — SonicScoop) it is capable of extremely fast attack times (20 microseconds ). The amps and transformers at input and output gave the unit a characteristic sound which quickly caught on and is still sought after today. When Bill Putnam Jr. resurrected Universal Audio in 1999 his first release was a hardware version of the 1176 utilizing the original INPUT AND output transformer design!

Revision A/B and B were released shortly after, but it was Brad Plunkett’s 1970 revision C that most now recognize, with its new black faceplate and its “LN” designation. This revision lowers the noise floor by 6 dB while shifting the noise frequency away from the “sensitive 500hz to 3khz range.”

The following three years brought revisions D and E and are considered the most sought-after models. The updates were as follows:

• D “UREI” added to faceplate and a reworking of the main circuit board to include the LN circuits which were encased in epoxy.
• E added a switch to change voltage.

In 2008, Universal Audio released the 1176 AE (Anniversary Edition) which revisits the program-dependent release of the Rev A “Blue Stripe” and sported black faceplates with blue anodized overlay as a tribute. It also features what the company called “the hot rod mods”. This introduced a 2:1 ratio borrowed from the 176, which also gives the user a wider palate of multi-button ratios to play with. It also includes a click-stop attack setting for “Slo” (10 whole milliseconds!)

Comparing the 1176 UAD Plugins In Use

With the 1176, the amount of compression applied to the signal is determined by the amount of input dialed in. The hotter the input the more compression. Switching your metering from gain reduction to output helps set a reasonable coarse level, which you can refine to taste with input adjustments and then setting output level.

Attack time depends on how much of the track’s transient attack you wish to have. The faster you attack the further back the track appears due to less transient attack. Be sure to adjust release so that there is no pumping and the track doesn’t feel late.

Note: Those plugins labeled as “legacy” are first-generation plugins and require less DSP processing to run. UAD points out that these plugins are a good choice when DSP constraints are a consideration. The SE version was created specifically to use less DSP. Recently I got together with my friend djtinonyc and we had a shootout between the Rev A, LN (legacy), Rev E, AE, and SE(legacy) model UAD plugins.

Bass guitar:

First up was a bass guitar. The Rev A provided a nice grit to the track but was the hardest to setup for a smooth bass performance.

Bass Rev A

The LN offered a very smooth performance and gave the track a fuller and smoother sound than the Rev A.

Bass LN

Rev E was very similar, but presented these traits in a smaller amount.

Bass Rev E

The AE was my favorite, giving the track a smoother-sounding performance with more of the attitude we got from the Rev A. The SE version lacked detail, and we both felt like it wasn’t something we liked on such an important track as bass.

Bass AE

Drums:

As parallel compression on the drums the Rev A really gave the drums a nice bounce while making the drum sound more aggressive. It also gave a nice high end presence to the kit.

Drums Rev A

Historically, by this point in the development of the 1176LN, the FET was reacting more linearly due to the LN circuitry and there were design changes to reduce distortion and re-tune frequency dependency which would affect release. As expected, the LN based on modified circuitry gave a smoother sound which was less aggressive and provided less bounce than the Rev A.

Drums LN

We felt the Rev E had more bounce than the LN while retaining a smooth sound.

Drums Rev E

The AE was similar to Rev E but more aggressive. We added some high frequency shelving afterwards which came extremely close to the feel and high end of Rev A.

Drums AE

Vocals:

(Editor’s note: Permission for soloed vocals were not obtained for purposes of this article.)

For vocals, the Rev A gave more presence and accentuated the head voice.

Less present was the AE, which as you might have guessed with its design leaning heavily on the LN design while still shaping it’s release more like the REV A, accentuated more chest voice.

In between the Rev A and AE was the Rev E, which makes sense as it would be the third revision of Brad Plunkett’s LN model placing its release in the middle of the two extremes. It was not as aggressive and exciting a sound, nor was it that complex, and we were less excited about it on the vocal.

The LN was a more complex sound and thicker sound than the others.

The SE, due to its design, featured the same characteristics but with less detail.

Summing it Up

Shooting out the 1176 plugin versions was considerably easier than rounding up the hardware versions!

One of the upsides to digital recreations was actually being able to access the various units. Had this shootout been between hardware units, it would have been quite difficult to obtain all of them, to say nothing of how far from spec aging components may become.

Being able to compare them side by side was also a surprising experience, in that it really introduced me to the differences I was less aware of. This exercise made me realize that by considering these differences, a mixer can make better choices about the revisions we use on a given track.

I hope this history of the 1176 and our observations help to guide you in your decisions while making music. To further guide you along there are several audio examples you can check out.

You can contact Rick at audiobyrickslater.com. Rick gratefully acknowledges input from djtinonyc, and American Zen Studio as well as the design team at Universal Audio in the creation of this article.

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