The second in a series of parallel tests of compressor plugins is a comparison of FET compressors.
As with optos, in the world of field effect transistor compressors there’s leaders and there’s followers [I’m not gonna let you finish that here, Kanye]. The epitome of FET compressors is widely considered to be the UREI 1176 Peak Limiter, and obtaining one is simply a matter of handing over $2,355/£1530 or, if you’re especially handy, winging it yourself. Of course, there are software solutions:
- Waves CLA-76 Compressor/Limiter
- Native Instruments VC 76
- Apple Logic Pro Compressor in Vintage FET and Studio FET mode
- Universal Audio 1176 Classic Limiter Plug-In Collection
- Antress Seventh Sign [freeware; Windows-only]
The 1176 has had a number of revisions since its launch in 1967. The first ones had a silver/blue look (‘Bluestripe’), while the later ones came in an all-black box (‘Blackface’). The various software incarnations mimic that distinction:
- Universal Audio offers the Rev A “Bluestripe” and Rev E “Blackface” (including a rare 1176AE 40th Anniversary Edition).
- Logic Compressor’s Vintage FET mode has a silver design and the Studio FET is black.
- Waves’ CLA-76 features a ‘Bluey’ and a ‘Blacky’ mode.
The silver units are generally said to produce higher levels of distortion (hence ‘vintage’). The black ones have the suffix ‘LN’, signifying their ‘low noise’ character. Let’s test this. I have compared the Logic’s Compressor in Vintage and Studio FET modes and Waves’ CLA-76 in Blacky and Bluey mode.
I recommend downloading the files, as Soundcloud transcodes to 128 kbps mp3 for streaming playback which isn't sufficient for this purpose. Just click on the download icon on Soundcloud and you'll get a full quality .wav file. Alternatively, click here to download all the files as a zip archive.
From the waveforms we see that the Vintage FET/Bluey modes in Logic/Waves do bring out the ambience due to the higher levels of distortion. Studio FET/Bluey smooths out the transients without bringing out the ambience. 
My observations:
- Waves Bluey saturates the fundamental of the hihat (~5kHz) and squeezes the ambience of the kick (a byproduct of saturation/distortion).
- Waves Blacky controls the transients and adds subtle saturation around the 5k area.
- Logic seems to lightly saturate the area around 10kHz. That doesn’t contribute much to the sound, especially on lower quality listening systems and/or bitrates. In Studio FET mode there’s some rattle from the kick.
To me the Waves CLA-76 Blacky sounds the best in this example. Which one do you prefer?
Test Notes:
Rather than typing out all the settings, here are the screenshots of the four plugins in which you can see the values I used. The drum loop is from Mike Reed/Mike the Drummer.
Automation Lane 