Retro Instruments: Retro 176 Limiting Amplifier

One of the hardest parts of writing these reviews is coming up with a good opening sentence. It's easy to get caught up in excess hyperbole when geeking out over pro audio gear, especially when you discover a truly amazing item that on one hand is fresh and exciting, and on the other hand is nothing new to recording. I already knew that Phil Moore understands how to recreate a classic when I reviewed the Sta-Level (Tape Op #55), but now with the edition of the 176 Limiting Amplifier, Phil has done it again and even more so. Like the Sta-Level, the Retro 176 is laid out very much like the original, with all the controls as expected. Its physical size and configuration are also like the original, including the exposed tubes and transformer in the back. It has the classic, hinged face, but Phil wisely added a cover to the top. It is a 2RU-height unit that is painted in an industrial grey and looks very much like the Sta-Level in choice of knobs and screening. Like the original 176 and 175B, it has controls for input level, compression ratio, meter selection, attack, sidechain HPF frequency, output, and release. Unique to Phil's version are switches labeled Interstage and Assymetry. As a recreation, the Retro 176 is a variable-mu compressor/limiter that can be heard as an audio time machine. It will take you back to the original sound of the classic UA 176 and 175B. The modern difference is it allows you to bypass the interstage transformer (modeled after the original UTC A-19) and reduce the amount of "tube" character and achieve a tighter and more transparent compression. With the interstage compressor engaged, you have a rich and full tube-sounding compressor that is ideal for bass and guitars and renders a sound that is equal to the original (see Sylvia's comments below), and in some cases, may be better due to the reduced noise floor derived from the use of modern components. This makes the 176 a very versatile studio tool. You can look at it as an 1176-style compressor with tubes, but that is oversimplifying its capabilities. In many ways, it's more like a Distressor with tubes, as it can handle any type of compression duties needed. The reason the Distressor is great is that it can mimic the behavior of classic FET or opto compression but then has the ability to create its own sounds when pushed into distortion. The Retro 176 also can faithfully recreate multiple types of compression algorithms through its input, ratio, attack, and release controls, but it also allows the user to really drive it to create really cool tones of its own. Through the use of the interstage selection, assymetry position, and sidechain filter, you can fine-tune how the 176 reacts to all manners of program material. We discovered how powerful these switches were on bass tracks. The Retro 176 allows you to completely reshape the bass envelope from subtle tightening and minimal dynamic impact to full-blown tube squash that propels the bass forward and brings out all the rock tone. And that's just playing with the knobs. Once we dialed in a bass tone we liked, we played with the interstage switch, then checked out which side of the wave we wanted to mess with via assymetry selection, and then tailored that signal even further with the sidechain filter. All this interactive control really lets you get a signal that maintains its presence and place in the mix even when it's surrounded by multi-layered guitars, horns, and strings. For vocals, I still love the Sta-Level when the vocalist has given us a great performance that just needs the love. But for singers with bad mic technique or poor dynamics, the Retro 176 is a real problem solver. Again, all the options presented by the controls allow you to go after bumps or sibilance and to fine-tune which characteristic of the vocal you choose to enhance. It's also great on all manners of guitars and really shines on acoustic guitars as you can decrease the low-end sound-hole muck without losing the bottom end of the instrument completely. What we have come to understand is that the Retro 176 is one of the most versatile and musical pieces of equipment we have had the pleasure to use. The more we use it, the more we are learning how powerful this unit is. Here's what Sylvia Massey, who owns a ton of vintage gear, thinks: "We've been using the Retro 176 for a while and have put it up against our original UA 175Bs on several different applications, including snare, bass guitar, drum room, and vocals. It's really a great unit. I especially like how it works on vocals and find it has the same sweet quality as the original 175B. It reacts very similar to the original; however, the Retro 176 is much more versatile. And much more stable. The engineers at RadioStar all had an opportunity to work with the Retro 176, and we all found it to be the most desirable single-channel limiter in the facility-which says a lot, because we have some great tube limiters and compressors here, including RCAs, original Gates Sta-Levels, Collins, ITA, CBS, Western Electric, Altec, UREI, Neve, etc. The only other compressor as highly sought after in the studio is our Retro Sta-Level!" At its $2995 street price, the Retro 176 is not going to be within many people's budgets, but considering that an original 176 of questionable performance could easily cost you this much, the Retro 176 is a great deal as you get all the tone and features of the original plus the modern power-user's extra controls that take the original sound to new levels. If you are serious about your tracking and mixing, this one is for you. We need three more now at WaveLab so we can have two to use on tracks and two to couple together for the stereo mix. Now that would be something! The Retro 176 is available through Vintage King (www.vintageking.com). ($3695 MSRP; www.retroinstruments.com)