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API 7600 Channel Strip

It's like deja-vu all over again" is one of baseball Hall-of-Famer Yogi Berra's most often repeated comments, which also pretty well describes my impression of the API 7600 channel strip. API is a real living legend of pro audio.

It’s like deja-vu all over again” is one of baseball Hall-of-Famer Yogi Berra’s most often repeated comments, which also pretty well describes my impression of the API 7600 channel strip. API is a real living legend of pro audio. Its core products (microphone preamplifiers and equalizers) are nearly identical to original 1968 designs, and have been in production almost continuously since then.
Product PointsApplications: Studio

Key Features: Mic preamp, compressor, three-band equalizer, 48V phantom power, 20 dB pad

Price: $2,995

Contact: API at 301-776-7879, Web Site.

The API 7600 ($2,995) channel strip combines the 212L mic preamp and the 225L compressor from its “Legacy” console – with an updated 550a equalizer in a single- rack-space mono channel. The mic pre and equalizer, according to designer Paul Wolff, are “as identical as humanly possible” to the originals, including the proprietary all-discrete API 2520 op amps and custom made transformers.

The 550a equalizer is modified only to include seven frequency choices per band rather than the five that were in the originals, and is otherwise the same in every respect. Boost/cut controls are in 2 dB or 3 dB steps and frequency choices are stepped generally in octaves. The high and low bands have switchable peak/shelf selectors, and in addition to an EQ in/out switch there is a band-pass filter switch, just like the original. The blue lettering used for the frequency scales and other panel markings is very hard to read against the black panel face in typical soft studio lighting. This particular aspect of the unit’s “true to the original” nature might have been better done otherwise.

The mic preamp has a gain knob, 48V power and 20 dB pad switches, and a seven- segment LED meter. The VCA-based compressor, designed in more recent years by Mr. Wolff, has knobs for threshold, ratio and release times, a seven-segment LED gain reduction meter, and buttons for compressor defeat, stereo link, fast or slow attack, hard or soft knee, and “new” or “old” type. The “old” type selects a level detection structure that is similar to the API 525 unit, as well as vintage UREI 1176 and Fairchild 660 compressors. The “new” setting’s structure emulates a more modern VCA based compressor.

One of the things that makes the API 7600 unique is its array of busses and sends, designed to enable users to combine several units together (along with the separately available 7800 master module, also a single rack space) to create a complete console. A theoretically unlimited number of 7600s can be summed together in the 7800, which was not tested for this review.

Each 7600 includes four aux sends with dedicated pots, each of which is separately switchable on or off and pre or post channel in odd/even pairs; one stereo and four mono bus assign switches; an output gain control; an illuminated solo switch plus a solo defeat (‘safe’) switch; an illuminated channel mute button; and a mute group button. The switch-defeatable stereo panner feeds a separate stereo bus and will also pan signals across odd/even pairs of program busses.

Multiple 7600s are linked together by two multipin connectors on the back panel, daisy-chain style. There is also a multipin connector to allow for substituting an outboard fader for the built-in rotary pot as the channel output master. Insert I/O connectors allowing the mic pre, compressor and equalizer to be used on separate sources, stereo link and side chain inputs for the compressor, a direct out, an outboard meter connector, an XLR mic input and a 1/4-inch line input fill the remaining space on the back panel.

There is a wonderful block diagram silk-screened onto the top panel of the unit (but unfortunately not duplicated in the manual) that makes the routing architecture of this surprisingly complex device easier to grasp. While the 7600 can be used right out of the box very simply as an all-in-one channel strip, taking some time to experiment with the almost unlimited alternative setups it offers will be well rewarded. As Yogi said, “When you get to the fork in the road, take it.”

API gear has always featured solid construction and quality parts, and the 7600 is no exception. A thick front panel, solid, heavy chassis and API’s classic extruded aluminum blue and silver knobs give the unit a timeless, confidence-inspiring look and feel. Removing the top panel for a peek “under the hood” was a little disappointing since most of the parts are covered by a top-mounted circuit board. Nonetheless, still visible were several large, impressive transformers, and one of the epoxy- encapsulated op-amp modules. From what I could see, build quality is first-rate. This is an expensive piece, and it looks it, inside and out.

In Use

I was fortunate enough to have two units to review, and used them in sessions on a wide variety of program sources including vocals, piano, acoustic guitar, flute, clarinet, cello, drum loop, snare drum, and mixed stereo program material, using both a 2-inch, 24- track tape machine and a Pro Tools Mix system with an Apogee AD-8000 24-bit converter as recorder/players.

A strong sense of the unit’s sonic “fingerprint” emerged from all these applications. I would characterize the 7600 as having a very forward, “in your face” presence, with a clear, clean high end and a robust but not exaggerated low end. Being a transformer-based design (there are five transformers in various places in the audio path), it had some of the fatness and warmth characteristic of my venerable Neve 1073 modules. It was also considerably cleaner sounding than the Neve. In my experience, vintage Neve modules are something of a benchmark where fatness and desirably colored tone are concerned in a solid state unit. They are quite famous for their enhancement of drum and vocal recordings (among many other things). One of the pleasant surprises though, when I acquired the Neves a few years ago, was that they became my first choice for recording acoustic guitar. I had not expected the distinctive Neve color to work well in that case, but it did — very well.

The first time I tried the API 7600s on stereo acoustic guitar, on a scoring session for a documentary film, they were easily as satisfying as my beloved Neves, and then some. The guitar, a Martin SP000-16TR, was miked in stereo, using a Lawson L47MP and a Rode NT-1. The 7600s gave it a “right here” presence and clarity that the Neves, great as they are, could not. By contrast though, for a track on a jazz/pop album where the guitarist was playing a somewhat thin sounding Ovation acoustic, the Neves worked better, smoothing over some of the instrument’s excess brightness.

On another film scoring session, I used the 7600 on various woodwinds (using mainly a Stephen Paul-modified U 87), and cello (using the Lawson L47MP). Once again, the instruments that benefited from some added presence and clarity (such as cello and clarinet) sounded great and the ones that had inherently abundant brightness and presence (such as flute and sax) worked less well. As with the Ovation guitar, the 7600s very forward sound was too much of a good thing on these sources.

I did numerous piano recordings including a track on a pop Christmas song, a classical CD, two musical theater soundtracks and some experiments playing the piano myself. The 7600 immediately proved itself as outstanding for piano, generally surpassing my previous default choice, a Drawmer 1969 Mercenary Edition with a Speck Electronics ASC equalizer. As in the other comparisons, the 7600 excelled in clarity and presence. The 1969/ASC combination was only preferable in cases where a somewhat darker, mellower sound was desired. Overall, the API was outstanding, bringing a tremendous sense of solidity and openness to the instrument. In my own piano recordings it was without question the best sound I have ever gotten.

Vocal sessions for one of the musical theater recordings offered another chance to try the 7600s on for size. Using a pair of Neumann U 87s, I recorded mixed male and female group and solo vocals using only the preamp and compressor sections, leaving the EQ bypassed. Similarly to the other cases, the APIs sounded best on voices with less inherent brightness.

For a pop guitar/vocal session however, the 7600 worked exceptionally well. A male songwriter’s project was the only “all API” session of the lot (all guitars and voices recorded though the 7600), and the final result was stellar: clear and clean, with lots of API “in your face” attitude, but without being strident or harsh. Wonderful!

I made some additional recordings of my speaking voice, using the 7600 with the Stephen Paul U 87. I am not a professional voiceover actor, but my voice has never sounded so good on playback. Once again: spectacular presence and clarity along with smooth transformer color and warmth.

Percussion has always been a great application for API gear, and the 7600s were no exception. In a mix of a hip-hop track, I used large amounts of both compression and equalization on an intense, complex drum loop containing elements covering nearly the entire frequency spectrum. It was just the ticket. The loop came to life with all the intensity I had hoped for. Likewise on a snare drum track in a pop/rock mix, a few decibels of boost at 200 Hz and 5 kHz gave it the perfect slammin’ sound.

Probably the least successful application for the 7600s that I found was on mixed program material. I do a fair amount of mastering as part of my business and had hoped that they might be useful as an occasional mastering EQ/compressor. Unfortunately, they were not very satisfying in either regard.

In fairness, these units are in no way marketed as mastering tools so that should not be counted against them.

While the mic pre and equalizer are outstanding, and are largely responsible for the unit’s distinctive sonic character, I found the compressor section, while useful in many cases, to be somewhat less satisfying. I felt I could usually hear a slight dulling of the tone when the compressor was engaged, although that was not always a bad thing. The various mode choices concerning attack, style and knee certainly made audible changes to the results, but the dulling effect was nonetheless generally audible.


“It ain’t over ’til it’s over,” Yogi once said. So to wrap it up, the API 7600 is an outstanding pro audio product that could easily justify its considerable price – even without the added ability to transform itself into a console. Its unique sound is truly special and proves that API has earned its status as a living legend. As a part of a well-equipped studio the 7600 fills a sonic niche currently unoccupied by any other product I know of. For the more ambitious, a real API console can be assembled from any number of them; either all at once or channel by channel as budget allows. Yogi would call that a home run.

Review Setup

Custom console; Genelec 1031a/1091 monitors; Stephen Paul-modified U 87, Lawson L47MP microphones; Neve 1073 mic pre/EQ, Avalon VT-737sp, Drawmer 1969 mic pre/compressor, Speck Electronics ASC equalizer processors and preamps; Otari MX80 2-inch, 24-track recorder; Digidesign MIX+ DAW; Apogee AD-8000 converters; Yamaha G2 piano.