Fast FactsApplications: Studio
Key Features: Single-channel analog recording strip; Class A mic preamp with variable input impedance; parametric EQ section with high-pass filter, high and low shelves and two mid bands; optical compressor; FET peak limiter; gain reduction and output metering; transformer/transformerless output circuit.
Contact: Buzz Audio at www.atlasproaudio.com (US distributor).New Zealand’s Buzz Audio released its first commercial pro audio product in 1993. Owner/designer Tim Farrant’s unique Class A preamp was originally inspired by an ultra low-noise moving coil pickup circuit Farrant had developed during his broadcast engineering years.
Lynn Fuston of 3D Audio was one of the first stateside engineers to extol the virtues of the hard-to-find Buzz MA preamp, which was later featured on his 3D Pre CD. Buzz Audio’s handcrafted products are no longer hard to find, thanks to their well-established high-end reputation and worldwide distribution.
Last year, Buzz introduced its ARC 1.1 analog recording channel ($3,500) featuring a discrete mic preamp similar to that found in the MA series, a top-notch parametric equalizer, an optical compressor section drafted from Buzz’ popular SOC 1.1 stereo optical compressor and a FET peak limiter. Outfitted with an immense array of controls and routing options, the ARC 1.1 is truly one of the most comprehensive and flexible recording channels available.
The Buzz Audio ARC 1.1 is essentially comprised of four separate sections: a microphone preamp, an instrument/line-level preamp, parametric EQ, and compressor/limiter. With the wealth of I/O connections provided, the ARC 1.1 can in fact be simultaneously used as four separate analog audio amplifiers/processors.
On the rear panel are Mic Pre In and Mic Pre Direct Out jacks (XLR), Line In and Line Loop Out jacks (XLR), and a line-level Main Out jack (XLR). A front-panel high-impedance instrument jack (TS 1/4-inch) is also provided. The Line Loop connection provides a hard-wired copy of the signal at the Line In jack for daisy chain/parallel-path purposes.
Also on the rear panel are EQ In and EQ Out jacks (XLR), and Comp In and Comp Out jacks (XLR), as well as a Sidechain Insert jack (TRS 1/4-inch) and a Compressor Link jack (TS 1/4-inch) for stereo operation of two ARC 1.1 units.
The front panel of the ARC 1.1 is logically divided into three main sections: input/output amplification, parametric equalizer, and optical compressor/FET limiter.
The mic preamp section features a Mic Gain knob (+9 to +50 dB of gain), a +15 dB gain switch, a 48V phantom power switch (with soft-start circuit) and a continuously variable 220 ohm to 5.5 k-ohm Mic Load control. The line amp input section features a Line Gain knob (0 to +40 dB of gain), -10 dB line gain switch, and a Balanced/Unbalanced toggle switch that selects between the rear panel XLR line input and the front panel 1/4-inch instrument input.
The last part of the front-panel I/O amplifier section provides the controls that pertain to the signal sent to the rear-panel Main Out XLR jack. These controls are comprised of a Mic/Line selector switch, Output Attenuation/Gain knob (providing an additional 10 dB of gain if desired), a combo normal phase/mute/reverse phase switch, and a main path/side chain path monitor switch. Also included in this section is a Clean/Tranny switch for switching in a custom-made audio transformer into the main path for added harmonic distortion and color.
The EQ section consists of a sweepable high-pass filter, semi fixed-frequency high and low shelving filters, and two bands of fully parametric equalization. Each of the five bands features a three-position
In (main path)/Ext (external rear connection)/SC (side chain path) routing toggle switch – see In Use for more on the ARC 1.1 routing options.
The high-pass filter attenuates at 12 dB/octave, and features a variable cut-off frequency range (3 dB down) of 25 to 450 Hz. The high shelf provides up to 17 dB of boost or cut in two modes: Broad or Tight. As its name implies, the Broad setting is a wide, gradual curve that starts at around 1 kHz and flattens out around 20 kHz. The Tight setting is a much steeper shelf that rises significantly starting around 4 kHz and flattens out around 20 kHz. The real inductor-based low shelf provides up to 17 dB of boost or cut in a fairly gentle curve at a 60 or 120 Hz turnover frequency.
The two fully parametric bands provide for up to 16 dB of boost or cut at continuously variable center frequencies of 30 Hz to 7 kHz (Band 1) and 160 Hz to 34 kHz (Band 2) at bandwidths ranging from .25 to 1.7 octaves.
The final section on the front panel includes the ARC’s compressor and limiter. The optical compressor features a Drive control (AKA threshold), a four-position ratio control (2:1, 5:1, 10:1, 20:1), a three-position attack switch (slow, fast, auto), a six-position release control (1, 2, 4, 8 and 16 x 100mS, auto) and a Comp Makeup gain control (0 to +15 dB). The compressor also features a dedicated 12-step LED gain-reduction meter, a Pre-EQ/Post-EQ/EXT path selector switch and a Mono/Stereo link switch. The peak limiter includes a 0 to +20 dB threshold knob, a three-position release switch (Fast – 100mS, Medium – 750mS, Slow – 2000mS), a three-position routing switch (In, Out, Ext) and a Limit operational LED.
Rounding out the front-panel controls are a 12-step LED level meter plus Over LED, and a mains power switch with LED. The level meter can be switched to monitor mic or line input level in the main path (as determined by the master mic/line selector switch), the main path output level, or switched off.
From both a design and use standpoint, this is an engineer’s recording channel: it is designed by someone with an obvious passion for audio circuitry and all the possible options afforded at each stage in the audio path, and it is best employed by recording engineers who appreciate being trusted with such a full range of control. Despite its 18 knobs, 24 toggle switches and 12 I/O jacks, I can picture Buzz’s Tim Farrant sweating over which features he would have to cut out to fit the single-channel ARC 1.1 into its 2-rack space chassis.
The first thing I did when I received the ARC 1.1 for review was to wire all its rear-panel jacks to my patch bay to maximize its routing potential. But before I get into the ARC’s routing flexibility, I want to talk about how it sounds. In a word, fantastic. The preamp is extremely quiet and pure, and its 15 dB gain switch (plus additional 10 dB available at the output stage) provides plenty of gain for even the quietest sources. The continuously variable mic impedance knob always enabled an excellent match with my favorite ribbon, condenser and tube mics (as well as an odd-ball assortment of dynamics). The not-so-subtle “Tranny” transformer switch added yet another colorful dimension to the palette, and its placement before the output gain stage allowed me to drive the transformer with the input stage to varying degrees while compensating for level at the output.
The EQ and compressor sections are as thoughtful and musical as the preamp section. The EQ section’s two parametric mid bands can craft subtle or surgical changes across the entire audio spectrum, and the more limited control of the shelving and high-pass filters proved to be the perfect tools to effect quick, overall changes. The optical compressor section also yielded excellent results, most notably in its ability to intuitively track bass and vocal performances with nary a hint of pumping.
In one of the most brilliant strokes of circuit-design creativity, the ARC 1.1 essentially features three discreet audio paths to which individual sections (and individual EQ bands) can be routed: main, external and side chain. It is by virtue of this flexible scheme and the inclusion of dedicated I/O per section that this single unit can be used to independently amplify and process up to four separate sources. In the short space I have left, I will attempt a reasonable explanation here, but I highly recommend checking out the well-written manual found on the Buzz website (www.buzzaudio.com) for in-depth info.
The main path is for the most “normal” use of the ARC 1.1 – i.e. as an all-in-one recording strip. This path routes the mic or line source into the EQ then compressor (or compressor then EQ) sections and out through the output gain stage and meter to the main output jack. Choosing the external path sends the compressor and/or limiter output signal to the rear-panel compressor output jack, and likewise, the selected EQ bands to the rear-panel EQ output jack. Setting any or all of the EQ bands to SC puts that signal into the compressor side chain circuit, allowing frequency-dependent operation of the compressor.
In an extreme example of the ARC’s flexibility, one could separately use the Buzz mic preamp via its direct I/O, the line or instrument input (with, say, the “Tranny” option, the high-pass filter and a band of EQ plus the peak limiter) through the main path, patch another source in and out of (any or all of) the remaining bands of the EQ section, and a fourth source in and out of the optical compressor. If you really want to get crazy, you can also send one of the bands of EQ to the compressor side chain to have one instrument affecting the compression characteristic of the other! Of course you could also do that without sacrificing an EQ band by making use of the external compressor side chain insert jack.
For me, a more common simultaneous scenario was to use the mic preamp patched into the EQ input (with the HPF set to Ext.) then back out into the compressor input and out to tape, alongside a DI on the line input routed through via the main path into the EQ and peak limiter and through the main out (with ‘Tranny’!) to tape.
The one omission on the ARC 1.1 – believe it or not – is its lack of individual EQ band on/off switches. In most cases, this is not a problem since bands can be taken out of circuit by simply setting them to S/C or Ext (assuming you are not using the EQ I/O). The only possible time this would be a problem would be if you have an EQ setting you want to turn on and off for A/B purposes and both the side chain and the external EQ I/O are in use.
The Buzz Audio ARC 1.1 is by no means designed for dumbed-down, streamlined set-and-leave use, but neither is it unintuitive or difficult to operate.
At its most basic operational level, the user will be rewarded with an excellent-sounding preamp, musically intuitive EQ and a smooth optical compressor section – everything one could want in a top-notch recording channel. For those with a more in-depth engineering sense (or those wanting to learn), the ARC 1.1 has the uncanny ability to instill in the user some of the same passion for audio creativity that so obviously went into its design.