Field Test: Studio Electronics C2s Compressor

Feb 1, 2004 12:00 PM, By Erik Zobler


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Studio Electronics started rackmounting Minimoogs and retrofitting them with MIDI in 1988. Soon after, the California-based company began to manufacture its own version of the Minimoog, which was based on Bob Moog's original analog circuits along with digital control, such as MIDI capability and user-memory locations. Now best known for its synthesizer products, Studio Electronics manufactures three completely discrete analog synthesizers: the SE1X, the ATCX and the polyphonic Omega Series synths. If you have ever heard a record with a smooth, single-voice synth sound (affectionately called a “worm”) or an incredibly fat synth bass sound, then chances are you have heard some of these instruments.


Studio Electronics bases its products on analog circuit designs that are both popular and proven by years of use. In 2002, the company released the C2s Dual Compressor, its first release in a series of high-quality, analog-based recording products that include mic preamps and will later include equalizers.

The C2s is based on the UREI 1176's design. Fans of the 1176 know that its design evolved from the Universal Audio 175 and 176 vacuum tube limiters designed by audio innovator and inventor Bill Putnam. In 1967, Putnam eliminated the tubes and began using Field Effect Transistors (FETs) as a voltage-controlled variable resistor to accomplish gain reduction. There were at least nine revisions (A through H) before the unit went out of production. Improvements included lower noise, circuit board revisions, and amplifier and transformer replacements. In 1999, UREI started manufacturing again and its current “re-issue” 1176LN model is based on the D and E revisions. Studio Electronics decided to make an “1176-type” compressor based on these same revisions, but with some interesting modifications.

On the outside, the C2s has the same input, output, attack, release and ratio controls as the 1176, making it instantly familiar in terms of use. The attack range is less than 20 microseconds to 800 microseconds, and the release range is 50 milliseconds to 1.1 seconds. It has the same ratio selections as the 1176, but instead of push-buttons, the C2s uses a six-position selector with Off, 4:1, 8:1, 12:1, 20:1 and Squash. The Off position allows you to run a signal through the C2s to add gain or a stage of analog “warming” by going through the transformers and amplifiers. The Squash position exactly duplicates the highly secretive practice of depressing all four of the 1176's ratio buttons at the same time. This is one of those engineering secrets that engineers and producers yearn to learn and Studio Electronics unabashedly gives it to us on Squash — an appropriate name in our current audio environment of “compress the snot out of everything.”


On the inside, SE has made some changes. The original 1176 used a UTC input transformer and a custom-designed output transformer; the C2s uses a Jensen transformer on the input. In addition, Studio Electronics puts the input attenuator on the secondary, rather than the primary, of the input transformer. The company claims that moving the attenuator reduces distortion and noise. Another change is the use of a Neve 1272-type Class-A output stage followed by a Sowter (made in England) transformer. The Sowter transformer is part of the vintage replacement series and was designed to work with the Neve 1272. There are substantial differences in the power supply design, as well.

Instead of using VU meters like the original 1176, the C2s uses LED meters with PPM ballistics. Each channel has output and gain-reduction meters that operate simultaneously. On the back, there are switches for input grounding and output termination. There is also a true relay bypass that allows signal to pass even if the unit is off. Finally, the C2s is a dual-mono compressor and there is a switch on the front to link the two channels.


Most of the alterations Studio Electronics made to the original 1176 design are more like substitutions than changes—analogous to using brown sugar instead of white sugar in a cookie recipe. Both recipes make good cookies, but they definitely taste different. I put the C2s through its paces and found that I liked it on almost everything except when I tried to use it as stereo mastering compressor. While the C2s is a “linked dual-mono compressor,” it does not seem to be designed for subtle input and output adjustments. Both the input and output adjustments are quite sensitive, and I found it difficult to set up in stereo, especially when trying to align inputs and outputs to tenths of a dB. This was not a problem when I used it on stereo sources and stuck my head between the speakers to adjust the stereo balance.

I found the meters on the C2s to be both useful and annoying. I loved having both output and gain reduction displayed simultaneously. However, the PPM ballistics are so sensitive that I often thought I was working the unit too hard, not because of the sound but because the meters were so accurately tracking the signal. If you are an engineer who needs to know just how much gain reduction is going on, then you won't like the fact that there is no value shown for each LED. (SE says output and gain reduction values have been added to the front panel in new production models.) The gain reduction meters use an exponential scale and go from 0 to 40 dB of reduction. The LEDs show 0, -2, -4, -6, -8, -12, -16, -20, -26 and -40. In what I would consider “normal” compression settings, the gain reduction was difficult to hear, which is normally a good thing! So after awhile, I didn't pay much attention to the meters. When I made the C2s pump and bark, the meters really went nuts, but then again, who pays attention to the meters when you crank it? And speaking of crankin' it, I think it is fair to say that the C2s really shines in this area. When it is working hard, this compressor sounds great. It gives you the compression you need with some attitude, and yet it still sounds clean.

One interesting feature of the C2s is mentioned in its very minimal manual. Because the C2s uses a Neve 1272 output amplifier, the manual states: “The C2s' output stage ‘symmetry’ pot can be adjusted to deliberately clip asymmetrically — a well-known 1272 trick, adding additional second harmonic distortion, which some users find quite pleasing.” This is a very cool feature, but in reality, how many people will go to the trouble to pull the unit out of its rack, remove the top and dive in with a screwdriver? Too bad they didn't implement this adjustment with a “color” or “asymmetry” knob on the front of the unit.


The C2s is the sum of proven parts that, when combined, provides something old and new. Because UREI already made a very good reproduction of the original 1176, Studio Electronics wanted to do something different that sounds as good, or better than, the original. I think they have. The C2s, which retails for $2,495, would be a welcome addition to any family of outboard toys.

Studio Electronics, 310/640-3546,

Erik Zobler grew up in New York, partied in Boulder, Colo., demonstrated in San Francisco and eventually migrated to Los Angeles. You can meditate with him

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