Sep30

Written by:Rip Rowan
Saturday, September 30, 2000 6:00 PM

If there's been one trend in music gear in the last couple of years, it's been cheap mics and prosumer tube preamps. They're everywhere. The explosion in home recording has instantly created a market for these devices, and companies have rushed to market with all kinds of products to help you keep your wallet empty.

Make no mistake about it. Many of these products are average at best. Some of them are pure-D crapola. But a few of the current crop of prosumer products are destined to be classics. Some of them will still be gracing the gear racks of the biggest studios in the year 2020.

dbx's Silver Series line of mic preamps and compressors is that company's attempt to make a high-water mark in the tide of prosumer gear. The Silver Series is a premium line of tube-based preamps and compressors, with models including a dual channel preamp w/ EQ and limiting (586), a dual channel compressor (566), and a single-channel preamp w/EQ, limiting, and compression (576). All of these units are offered with optional digital I/O. For our review, we had a listen to the 576, so that we could evaluate both the preamp and the compressor.

The Rundown

The dbx 576 is a true tube preamp, not a reflected-plate design like some low-cost preamps. The classic tube design utilizes a parallel triode, class-A design with high plate voltages and premium 12AU7 tubes. The tube stage is coupled with a low-noise solid-state circuit for additional gain. The quality construction and attention to detail results in an amplifier design with an EIN of –126 dB and a wide bandwidth all the way out to –3 dB @ 200 KHz.


Controls are plentiful. Separate Drive and Level controls allow independent control of the input and output stages of the tube section, offering full gain with either heavy or light tube saturation. The preamp offers an insert allowing the user to patch another device, such as a de-esser, into the circuit. The preamp section offers a three-band EQ with high and low shelving and a mid boost / cut with swept frequency control. A notch switch allows the mid-EQ to cut annoying frequencies.

The compressor features variable hard / soft knee compression, a separate tube gain stage, variable threshold, ratio, attack, and release, and yet another limiter. The sidechain allows the user to place an EQ or other processor in the compressor's detector circuit to perform de-essing or other compression effects. A low-frequency contour switch lowers the low-frequency content fed to the detector circuit, reducing pumping in program material with heavy bass content. An Auto switch offers automatic attack and release, overriding the manual settings. When the auto attack and release setting is combined with the OverEasy soft-knee compression, the compressor emulates the classic dbx units like the 165.

Metering is excellent. Two meters are provided, each with a number of metering options. The meter on the preamp can monitor the gain at the tube stage, at the output, or at the insert return. The compressor's meter can be used to monitor the gain of the tube stage, the output, or the gain reduction. Each limiter is provided with a "Limit" LED which lights to indicate the limit has been hit. Additionally, peak LEDs monitor the output of both the compressor and preamp.

The unit is well-appointed with all the inputs and outputs you'd want. The 576's preamp and compressor can function as completely independent units, each with its own inputs, outputs, and inserts. The inputs and outputs of both preamp and compressor can be set to –10 dBV or +4 dBu, a really nice touch. The only real difficulty with installing the 576 in your rack will be deciding what routing scheme you want to use.

Listening Tests

I have had the privilege of using the 576 for several months, and man, what a preamp.

First of all, this preamp is capable of extremely clean and pristine sounds. Unlike most of the prosumer tube preamps, the 576 isn't particularly colored or "covered-up".Au contraire, the 576 has a remarkably clean and detailed high-end, tight, well-defined bass, and rich mids. The unit is incredibly fast and responds extremely well to high frequencies and fast, powerful transients. I spent a lot of time listening to the sound of the preamp alone (with the EQ and compression switched out) and it just sounds wonderful. Sorry, I've run out of drippy superlatives.

When I focused on the sound of the EQ I was underwhelmed. It's fine, and it does what it's supposed to, but it's not special. It's EQ, plain and simple, and maybe too simple. Perhaps a fully-variable width (Q) control would have made the EQ more versatile. Most of the multifunction mic preamps I've worked with in the last year have had a four-band EQ, or a variable width, or both. The mid control is OK, but the "narrow" EQ setting isn't quite narrow enough for surgical EQ applications. The shelving low and high controls, utilizing typical 80 Hz and 12 KHz knee frequencies, are perfectly usable. But don't expect anything magical from this EQ. After several months with this unit, the EQ was the only aspect that I felt should be better.

I liked the PeakPlus limiter. Of all the preamps I've used recently, this limiter gets it right. It's reasonably transparent, is fast enough to be a failsafe against digital clipping, and when you really slam it, it responds with all kinds of harmonics. When recording the Happiness Factor CD, Salim (the singer) socked it to me a couple of times, slamming the limiter and causing the Peak and Limit lights on the preamp to light up and stay lit. I was sure I had lost a take, but the harmonic distortion was sweet, not scratchy, and the take was not only usable, it was excellent.

The limiters were also perfect for fattening up kick and snare drums. I have yet to find a preamp with a better limiter, and the 576 has not one, but two! The dual limiters allow you to set up the preamp limiter to catch freak transients from the mic, then compress, and use the compressor's limiter to catch any freak transients from the compressor. Or, you can run the preamp's limiter hard, squashing and distorting the signal, add some transients back using the compressor, then control the compression transients with the compressor's limiter. Or, use the preamp and compressor as completely independent units each with its own limiter. Sky's the limit, and it all sounds great.

I found the compressor to be outstanding on vocals in particular. When used with a moderate ratio setting (3:1 – 5:1), Auto attack and release, low-frequency contour, and OverEasy compression, the compressor kept the vocals up-front and present without any audible artifacts, even when driven into deep compression. Killer compression, killer sound.

Conclusions

For a perfect example of the 576 in action, take a listen to the Happiness Factor song, "Hold" on their MP3.com site. The song's vocals were recorded using my Groove Tubes MD2a into the 576. The Martin acoustic guitar was recorded with an Alesis AM40 tube mic in omni mode into the 576. The vocals range from smooth, quiet, sweet sounds to full-out screaming. This was the song where Salim overloaded the preamp and squashed the limiter. You can hear it clearly in the middle portion of the song, where he really belts it out. I'm sure you'll agree that the 576 is capable of getting a vocal to sit sweetly in the mix, whether the vocal is smooth or screaming.

The next question is, "Which one is right for me?" That's a tough one. Usually, I'm not a huge proponent of outboard compression, preferring to record at 24 bits and compress with software compression. However, the Silver Series compressors are great! So, to me the question is: do you envision wanting to use the unit in stereo? Or are you looking for a mono "gold channel"? If you have a good software compressor, and want stereo preamps, then the 586 is the unit for you. You'll get two channels of preamplification, EQ, and PeakPlus limiting. Then there's the 566: with dual linkable compressors and limiters, it's a great choice for 2-track compression and limiting. If you are still working with an analog mixer, and mixdown to DAT, the 566 (with built-in digital converters) would be a perfect choice for a mixdown compressor / limiter.

dbx has some real winners with the Silver Series. Whether you need a mic preamp, a compressor, or both, the 566, 576, and 586 will get you there in real style. These units sound excellent and will hold their value well. These preamps and compressors are instant classics, and you'll be seeing (and hearing) these units for years to come.

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