Stage-Sound-Tech-23-Modular-Outboard
By Jon Burton
As another small-format modular electronics system is launched onto the market this year I made a mental note of the
ones I had bought into and passed on. If you are as old as I am then maybe you are familiar with the SCAMP rack, the
Rebis or the dbx 900 modular systems.
The first of these, the SCAMP (Standardized Compatible Audio Modular Package) system was available between 1976 and
1984. This modular audio processing system was manufactured by Audio & Design Recording (ADR) and featured a standard
racking frame that could accommodate up to seventeen one-inch modules, all powered by an external power supply. A
smaller half-width rack version was also available, which included an integrated power supply and could hold six
modules. Some studio colleagues had the smaller version and started to use it for live shows.
It is worth mentioning that this was the late seventies, the world was analogue, and the standard FX rack for a live
show was pretty small. Inserting compressors and noise gates into a mix at a concert was still considered a luxury. The
SCAMP was reasonably priced and had a compressor, equaliser, noise gates and even an Automatic Double Tracking (short
delay) option. The compressor was based on a well-respected ADR design, the Compex, and sounded pretty good. However,
the unit was designed, like much of the audio equipment of the time, for studio use. It was based on a tall standard
computer mainframe card slot design, and the cards would fall out.
I didn’t own a SCAMP, it was way beyond my budget, but I did buy a rival system by British manufacturer Rebis, that
offered an even wider range of modules, based on another standard, but smaller-sized, Vero card frame system. This was a
more rugged system, and I still have a functioning unit, but it never really caught on.
The concept behind these systems was to use an easily and cheaply constructed card system, sharing a power supply, in a
standard 19-inch rack width. The SCAMP managed 17 cards but was about 6 units tall. The Rebis was 3 units tall and a
tidy addition to your FX rack. However, they didn’t catch on. Instead, it was a heavy-weight player from the States that
launched what I consider to be the first internationally successful modular rack system, dbx.
The dbx 900 series was launched in the early 1980s and was built into a sturdy metal 3u rack. Each rack was powered and
held eight modules. Initial modules were simplified versions of its existing range, such as the 903 compressors, based
on the popular dbx 160 design. It soon became popular as tours started specifying more and more complex requirements,
gates and compressors on multiple channels. With a couple of 900 racks, you could have as many compressors and gates as
you could possibly need (or so we thought).
The popularity, particularly in the United States, of dbx meant these racks started finding their way onto many tours as
well as clubs and other installs. More importantly, the format was opened up to other companies, although it was only
really Aphex who adopted the format. However, by the 1990s there were about 16 different modules available, including
the Aphex Aural Exciter, Dominator and Compellor. These modules are still sought after, especially the dbx902 De-Essor
which still sells for around $300 online. This is partially a testament to the quality of the circuits, but also the
ruggedness of the build. I was still touring last year with a two-channel dbx FS900 mini frame with a couple of
compressor boards fitted. It was this successful design that paved the way for a more successful product, the 500 series
rack.
So where did the 500 series come from? It originated in 1967 when Lou Lindauer and Saul Walker began designing modular
mixing consoles, co-founding Automated Processes, Inc. (API). Recording engineers started removing modules, including
the now legendary 512C preamp, 525 compressor, and 550 equalisers, from API consoles and installing them in homemade
mounting systems in the mid-1970s. The first commercial standalone rack was produced in 1978. A significant development
came in 1985 when Paul Wolff acquired API and introduced the "Lunchbox" - a portable chassis available in 2-slot,
6-slot, and 10-slot configurations.
However, it was in 2006, when API established the VPR Alliance that the system took off. To ensure compatibility across
manufacturers the alliance set specific standards including voltage requirements of +/- 16 volts and +48 volts for
phantom power, a maximum current draw of 130mA per slot and standardised physical dimensions.
The format experienced a surge in popularity and by 2020, over five hundred different modules were available from
various manufacturers including Neve, SSL, Aphex, and dbx.
So, is there room for a new analogue small-format modular electronics system? Well yes and no. The ubiquitous 500 series
covers most needs in the analogue realm. However, I was very conscious when touring last year that I was one of only a
handful of tours with an analogue console. Those days are pretty much over, and my current touring act is on a digital
board. Like many engineers, I still like to have some analogue outboard, but interfacing is an issue. I am not going
back to cable looms and patching systems, I want the convenience digital offers.
The adoption of protocols like Dante and AVB has made complex audio routing simple and easy. Any new modular system
needed to be able to interface with any host mixing console on those terms. The ability to save and recall settings we
now take for granted, computer control should be able to offer that seamless experience even with analogue circuitry.
Latency will always be an issue, but latency stability is now improving. What will be needed is what ultimately killed
off the 900 series but breathed life into the 500 series, the popular adoption of a well-considered and practical
standard by multiple manufacturers, in a way that is accessible to start-up developers. It will be interesting to see
what happens over the next few years as beloved modular analogue circuitry moves into the digital realm.