The preamp amplifies the mic’s signal by approximately 30–60dB to line level (normally referenced as 0dB); however, amplification is never totally transparent. Any preamp imparts certain characteristics to the signal—particularly regarding transient response and tonality—so the quest for quality mic preamps is part of the path toward pro-quality recordings.
It doesn’t take long for the average engineer to realize that the inexpensive mic pres built into a $300 interface may not be up to capturing powerful, dynamic sounds. In fact, the quality and sonic characteristics of mic pres can be as influential as mic selection. Even a high-end condenser mic can sound thin, cheap, and boring when subjected to an inferior preamp.
Yet it’s a fact of life that high quality mic pres require costly parts (transformers, tubes, chassis, potentiometers, etc.) and manufacturing techniques; they also usually require a significant investment. With price tags of $1,000 and up per channel, bang for the buck is crucial.
Enter the 500 series modular system, introduced by API many years ago. This consists of a metal frame with an internal power supply, along with input and output connectors that hold up to six of the company’s modular products. After this initial investment, you can purchase additional preamps, EQs, and compressors without the added cost of a chassis and power supply.
THE 500 SERIES FORMAT: HERE TO STAY
Companies other than API started creating products that would fit into the already existing “lunchboxes,” as the frame came to be called, and use the same power supply and connectors. As the format’s popularity increased, these manufacturers even began production of their own housings for 500 series devices. These units hold from two to 11 devices and come in portable, tabletop, and rackmount configurations.
But before you pull out the checkbook for a lunchbox, consider the format’s pros and cons. Pros include:
• A significant per-unit savings over comparable stand-alone preamps. • Up to ten can fit into a three-space 19" rack—that’s a lot of gear. • Cabling the units is neat and easy. • The widespread acceptance of the format guarantees more offerings from manufacturers in the future. • Portability—you can transport your favorite 500 series devices from one studio to another in a neat, lightweight package.
And for equal time, here are some limitations:
• The initial investment in a rack/power supply is between $300–$700. • Due to their small size, features such as 1/4" inputs, EQ, and high pass filters are often not included. • Their size also limits the size of internal components—you won’t find large numbers of tubes or bulky transformers.
The opportunity to compare large numbers of top-shelf pres is both a great privilege and sometimes a dreaded task. For our tests we acquired a Pro Tools|HD rig (with 192 interface), 14 pres, and two API lunchboxes— all tested using ace musicians.
Our first test tried each pre on kick, snare, and overhead. We used an Electro-Voice ND 868 on kick, Shure SM57 on snare, and Neumann KM100 as a mono overhead. Our second test was with a KM100 on a Martin HD28v acoustic guitar. Next, we re-amped distorted guitar (Radial Engineering X-Amp into a Marshall JCM800 head through a Marshall cabinet, loaded with four Celestion vintage 30s, and miked with a sure SM7B). We also tested those units incorporating 1/4" DIs on the front panel with a ’71 Fender P-Bass and Yamaha Motif keyboard. For vocal testing, we amplified pre-recorded vocal tracks though the mic inputs, courtesy of a level-matching transformer that converts line level signals to mic level and impedance.
Overall, the quality, workmanship, and sound of every pre we tested was exceptional. All pres fit snugly in the rack and had no mounting issues; each unit also featured a thick metal front panel with both phantom power and phase reverse switches (or buttons). I was astounded by the sounds we were able to capture using this unbelievable arsenal of preamps, and so were all the other engineers that were present—so, let’s look at what we found out. (Note: The following prices are list prices.)
PURPLE AUDIO BIZ MK AND PANTS
STRENGTHS: Input and output metering and level control. Switchable input impedance. Lit switches. Low price. Switchable dual-gain stage.
LIMITATIONS: Use of line mode often needed to avoid input clipping.
These two pres are very useful, and although they look very similar, have their own distinct characteristics. Both units offer helpful tri-color LEDs for both input and output level, as well as an impedance toggle switch and 1/4" DI inputs.
The Biz Mk is very aggressive-sounding— great for “in your face” mids, and tight lows. It excels on cutting rock vocals and distorted guitars, and its 1/4" inputs are great for keyboards. The unit offers 35dB of gain in line mode, 60dB in mic mode, and 75dB with the “dual” button depressed (note that we sometimes had to use the line mode when tracking loud sources to avoid clipping). When using a pair, I was astounded at the stereo imaging and clarity when tracking the Motif with a piano sound on a rock song. If you want a pre that knows how to cut through in a mix, this is the one.
The Pants has a much thicker low end with full low mids, which works well on thin sources that need fattening: rap vocals, snare on heavy music, kick drum, and line in bass guitar all benefit. It offers 40dB of gain in line mode, 60dB of gain in single mode, and 75dB in high mode. The Pants has very big lows and a pronounced top with smooth mids; when tracking vocals, it caused my U87 to sound much bigger than normal, with a nice top end presence for loud rock and punk vocals.
GREAT RIVER MP-500NV
STRENGTHS: Input and output metering and level control. Ultra-solid build quality. Switchable loading.
LIMITATIONS: Requires two slots in a 500 rack.
Occupying two spaces in the 500 chassis, the 500NV is particularly well-built, with a 6-segment LED meter for both input and output. The preamp’s basic coloration is a huge clear low end, smooth mids, and a nice top end presence. Kick drum and vocals were our fave applications. The front panel 1/4" DI yields the same huge low end, with great cutting highend clarity and presence. My Neumann U87 had more beefy low end, with musical highs, than any other pre I’ve tried on loud rock vocals. The unit also features a switchable input impedance for extra tweakability. The 500NV offers 70dB gain, along with a pad and output level control.
LACHAPELL MODEL 583S
STRENGTHS: Lit front panel switches. Top quality build. Tube amplification circuitry. Output level control.
LIMITATIONS: Takes up two slots in a 500 rack. No metering.
This is another solidly-built unit that also occupies two slots of a 500 rack. It’s one of two tube-based (ECC83/12AX7) units in this group of pres, which yields a definite sonic signature: huge, musical lows with lots of body, smooth mids, and particularly sweet upper mids and highs. Standout applications for this pre are acoustic guitar, bass/keyboard direct via the 583S’s 1/4" front panel input, kick, snare and overhead where you want a big open sound. It’s not a particularly cutting pre, but its very musical sound also exhibits a little compression, depending on the relative input and output level settings. It offers 70dB of clean gain and a 20dB input pad; the clever lit front panel switches make for a very sweet-looking unit.
STRENGTHS: Low price. Input level metering. Variable input trim. Dualcolor lights in all switches.
LIMITATIONS: No 1/4" DI input. No output level control.
Si offers a transformerless design and 72dB gain, with a 10dB output trim. One of its key features is 10-segment metering. While metering isn’t offered on all the pres, it’s a handy and desirable feature.
The Si has a big, open, round sound with fine overall balance—great for reproducing deep lows with plenty of punch and smooth highs, with a shade less upper mids than some of the other pres. The 10-segment metering precludes having a 1/4" DI, but there is impedance switching. This pre is the least expensive one we reviewed and is a great value; it impresses on kick, snare, overhead, and acoustic guitar.
AVEDIS AUDIO MA5
STRENGTHS: Switchable 28kHz boost circuit. Extra-solid build. Output level control.
LIMITATIONS: No 1/4" DI input. No metering.
This elegant, sturdy, simple pre features 70dB of gain and an output level control. It’s a Class A unit with a sound reminiscent of vintage Neve preamps—superb transparency, the characteristically Neve silky top, and some of the most massive low end on kick drum of any pre I’ve tested. The MA5 has one unique feature: a 28kHz high end boost, which purports to add “air” or openness (even though that’s theoretically above the range of human hearing, the filtering extends into the audible range). We found it sometimes a nice addition for acoustic guitar, piano, and drum overheads. Good applications for the MA5 would be almost anything not needing aggressive mids: kick, overheads, vocals, bass guitar, and keyboards. There is no 1/4" DI, so consider teaming it with a direct box.
BUZZ AUDIO ELIXIR
STRENGTHS: 4-LED level meter. Switchable input impedance. Mute switch.
LIMITATIONS: No output level control, although gain is sufficiently detailed that an output control is likely not needed.
The Elixir uses a transformerless input with Class A design, and offers 22–70dB of gain (10dB less for the 1/4" DI) and a 20dB pad along with a handy 4-LED level indicator, low/high impedance switch, and mute switch. The Elixir is a solid performer with outstanding overall tonal balance—I especially liked its 1/4" DI input on bass guitar; the massive lows and balanced mids make it suitable for kick, snare, and guitars that need a hefty low end enhancement. The Elixir seems a great general-purpose pre for any source, as the sound leans a bit towards big lows with overall good mids and clarity.
A-DESIGNS P-1, EM-BLUE, EM-GOLD, EM-RED, EM-SILVER
STRENGTHS: A-Designs’ units come in 5 “flavors.” 20db pad. Very solid construction.
LIMITATIONS: Lacks metering. No output level control.
A-Designs sent us five pres for evaluation. The P-1, EM-Blue, and EM-Silver units offer 65dB of gain while EM-Red and EM-Gold offer 63dB gain, all using a continuously variable pot. They also include a DI input and a -20dB pad. While all share a big/bold sound, feature set, and cosmetics (except the front panel color), each has a distinct sonic signature.
While all five pres are multi-purpose, A-Designs has varied each pre’s character by using different combinations of custom-made input and output transformers, making each a little better-suited for specific applications. The P-1 has a pronounced upper mid/top end and solid lows with smooth mids—it’s ideal for vocals, overheads, direct keyboards, and acoustic instruments. The EM-Blue offered a great overall balance with a little more high mid and top end air; that extra high-end “zing” helps dark snare sounds, or vocalists who need additional definition. The EM-Silver serves up a thick, slightly extended low end response with very smooth mids and slight low mid dip. It’s our favorite of the five for kick drum, bass guitar, direct synths, and other low end sources. I also had good luck with soft, intimate vocals.
The EM-Gold creates a similar low end to the Silver, but with slightly pronounced upper mids. It’s useful for sources that need strong lows and very good definition (heavy distorted guitars, rock vocals, drums that need both thud and attack, etc.)—it’s the smoothest pre of the group. The EM-Red is excellent for thick sounds that need a little less top; the mids are strong, and have a “woody” quality. I really liked the Red on bass guitar and electric guitars that need plenty of beef without the sometimes annoying top end buzz. Its slightly darker top also works well on overly-sibilant vocalists.
ROLL MUSIC SYSTEMS TUBULE RMS5A7
STRENGTHS: Tube amplification circuitry. Very substantial chassis. Cool old school button-style switches. Input level trim.
LIMITATIONS: No metering or output level control. No DI input.
Using a tube (with a high-voltage plate supply) for amplification, the RMS5A7 has a 10dB variable input attenuator, and a gain control switch that goes from 33 to 66dB of gain in 3dB steps. It also features a 20dB pad and a wellmade chassis. The Tubule was very evenly-balanced over the entire frequency range and it seemed just as comfortable on kick, snare, overheads, guitar, bass, or vocals. While not as aggressive-sounding as the solid state pres, the Roll Music’s Tubule delivers what you want from a top-shelf tube pre: big, solid tube lows with no harshness, and great overall balance.
STRENGTHS: Variable impedance. Swappable iron/nickel transformers on inputs and outputs. Clip light. +THD for adding harmonics. Gain boost switch. 8 LED front panel buttons.
LIMITATIONS: Lacks metering and output level control (although 1dB gain detents pretty much obviate the need for a “fine tuning” level control).
The Juggernaut is easily the most feature-packed preamp we received. It features 12–70dB of gain, iron and nickel input transformers (you can swap out one for the other in about 30 seconds, thanks to two screws and a clip), variable input impedance, a mute button, clip LED, and “+THD” (a 10dB output pad). This pre is so flexible, it’s the sort of device that offers an engineer nearly infinite tweaking options. In general, the iron transformer yields huge lows for tracking kick, snare, or bass guitar, while the nickel input transformer favors guitar. There’s also a 300–10k ohm dial impedance switch and 1/4" DI inputs. While recording bass guitar through the Juggernaut, it sounded a bit less “stiff” than many DI sounds— almost more like a miked bass amp. The unit also features lights on each of the eight front panel buttons, and pots with 41 detents (and aluminum knobs) for gain and impedance.
In general, we were floored by these pres: The sonic variety and overall quality was simply astounding. Clearly, the years of obsessive design and craftsmanship invested by these manufacturers has really paid off; after about a month of testing, I am now a confirmed 500 series junkie. In fact, I plan to purchase at least three channels of these incredible units.
These pres gave my current projects some fresh inspiration, and a seriously-needed sonic shot in the arm. Our thanks go out to the designers and manufacturers for supplying the units for this article, and more importantly, their endless hours of exceptional design work. Now, where did I put my checkbook. . . .