Thursday, April 16, 2015

Home Recording Review! The API Channel Strip: EQ/Compressor/Preamp


Home Recording Mic Preamp/Compressor


Brevis...
Price $2,995
Likes: Sonic attributes, ease of use
Dislikes: it’s analog perfection...


by Steven Murphy

By common definition, audio channel strips, whether the hardware or software variety, provide recordists with a complete set of tools to get an audio signal onto "tape." They are designed to emulate a mixing console channel strip and are, more often than not, modeled in the image of the classic analog “gods” found in major studio control rooms of yesteryear.
While it seems that nearly every studio audio manufacturer offers some version of a channel strip, API's The Channel Strip, priced at $2,995, offers the home recordist a unique opportunity: a complete, all-discrete analog console channel whose individual modules are ported verbatim from original API console designs. In short, it's not an emulation or some sort of Franken-creation; it's the Real Deal!

Features
The made-in-USA, (Jessup, Maryland, just 30 miles up the street from me) Channel Strip is a single rack-space unit comprised of four of API's famous 2520/2510 op-amp-based module stages: a 512C preamplifier, a 527 compressor, a 550A equalizer and a 325 line-driver output stage. A flip switch ("Post EQ") reverses the default signal flow of the two internal modules as described above, placing the EQ module before the dynamics module. Both the compressor and EQ modules include relay-based hard bypass switches, removing the respective module completely from the signal path.
The 512C preamp module accepts mic and line signals via rear-panel XLR and 1/4" TRS jacks, respectively, and high-impedance instrument inputs via the front-panel 1/4" jack. The input module provides up to 68dB of gain, a pad (-6dB line, -20dB mic), switchable 48V phantom power, polarity inversion, and an input-type selector that doubles as a +27dBu peak indicator.


As always, the tone-crafting control of the classic 550 EQ was a joy to use, whether dialing in some subtle air on a singer or exaggerated bass on a drum sample. Likewise, the 527 compressor performed beautifully on dynamic jobs great and small with characteristic API aplomb.

The VCA-based 527 compressor module closely resembles the designs found in the API 225L module and 2500 stereo bus compressor, the latter being one of my all-time favorite processors. Despite its limited real estate, the 527 packs an amazing array of both common and innovative controls, making it one of the most flexible compressors on the market.
In addition to a 10-segment gain-reduction LED and discrete threshold, attack, release and ratio controls, the 527 also boasts selectable hard/soft knee, an old- or new-type compressor style switch (determines placement of the RMS detector in the circuit for smoother 1176-style compression or newer, more aggressive compression) and API's patented "Thrust" control. The latter places an inverse pink-noise energy curve before the RMS detection circuit which, in brief, reduces the amount of bass driving the compressor action, resulting in less bass-pumping and a more transparent and punchy signal overall.
A link switch engages the rear-panel DC Link 1/4" jack for DC-summed multichannel/multiple-unit operation, and a switched 1/4" side-chain input jack feeds the detection circuit with an external signal.


Nothing but analog connections

The next module is the revered API 550A "Proportional-Q" equalizer, the history and development of which is well worth a search on Google -- an absolutely fascinating story. Essentially the same as when it was originally designed by Saul Walker over 40 years ago, the 550A in default mode provides three bands of peaking EQ, each with seven selectable frequency centers and up to 12dB of boost or cut. The high and low bands can be individually switched to shelving filters, and a separate band-pass filter can also be engaged (-3dB at 50Hz and 15kHz). The frequency ranges of the three bands overlap, and the fully reciprocal and stepped boost/cut settings mean that EQ changes can easily be repeated (or even undone).
The final module on the front panel is the high-headroom (+30dB) API 325 line-driver. This 2520 op-amp and 1:3 transformer-based output stage features an output level control, a remote-controllable (DB-9) soft mute switch, and a 10-segment LED VU meter that can be switched to display the 512C preamp output or the 325 output level.


The audition
Let me get right to the point: I am a long-time API fan and make no apologies for it: API makes fantastic gear that has special appeal for many, many engineers. Additionally, I have used and/or owned all of the modules (within and without console) that make up The Channel Strip, so their respective operations and high-quality signal paths were no surprise to me. What is gratifying is to see API assemble the same in such a thoughtful, complete and professionally satisfying package.
To wit: While the typical channel strip includes just the minimum I/O jacks, locking your signal in for a ride through its internal paths, API provides a generous and professionally complete set of rear-panel connections on The Channel Strip. In addition to the aforementioned input, side-chain and DC-link jacks, The Channel Strip boasts half-normalled preamp, first effect and second effect outputs, and normal-breaking input points for first effect, second effect and insert return (aka line-driver input, switchable at the 325 module controls). Essentially, API has provided all the I/O points found on its large-format console patch bays, allowing the user to employ the four modules separately and simultaneously or in any combination or division, lunch box-style, or as a complete channel strip as normalled.


The ultimate beauty of The Channel Strip is that each of its components competes expertly with many of the high-dollar separates I use or own but, taken together, it is an analog tracking masterpiece that, at present, has no equal.

Having the highly flexible Channel Strip on loan for a couple months allowed me to use it on a variety of audio recording projects, including numerous vocal sessions, bass guitar, acoustic and electric guitars, as well as post-recording insert modules. As always, the tone-crafting control of the classic 550 EQ was a joy to use, whether dialing in some subtle air on a singer or exaggerated bass on a drum sample. Likewise, the 527 compressor performed beautifully on dynamic jobs great and small with characteristic API aplomb. In the "Old" compressor setting, the 527 excelled on my vocal and bass recordings (the latter with the "Thrust" control in), while the "New" mode was fantastic on loops and samples, and some of the more in-your-face vocals I recorded.
The ultimate beauty of The Channel Strip is that each of its components competes expertly with many of the high-dollar separates I use or own but, taken together, it is an analog tracking masterpiece that, at present, has no equal.


The verdict
The API Channel Strip provides a top-notch recording experience for those who, like myself, love to dwell in the analog audio component world. If your budget allows it, I could not recommend a better all-around processor/mic preamp modular package. It easily earns the Everything Audio Network Stellar Sound Award.


Steven Murphy has spent the last 25 years engineering and producing in the professional broadcast, post-production and studio markets. He has engineered Grammy-Award winning and Gold/Platinum-selling releases. He now works from his state-of-the-art home studio in Washington, DC. He can be reached via his web site, www.smurphco.com

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