What Is 500 Series Gear
Introduction
Modular audio formats have always had their fans, but their popularity is soaring now more than ever. Still, many people aren’t familiar with this kind of gear, and one of the first questions they ask is: “What are the benefits of getting into 500 Series gear?”
With 500 Series equipment, you get a whole new level of customization. Unlike traditional studio setups that revolve around one console, the 500 Series lets engineers mix and match products from different brands. Instead of choosing between an API preamp or an SSL EQ—and having to buy an entire API or SSL console—you can easily have both in your signal chain.
In this article, we’ll give you a clearer explanation of what a 500 Series unit is, how you can use it to your advantage, and whether collecting modules is right for you. We won’t discuss specific models here, since we’ve already covered those in separate articles (linked below).
What Are 500 Series Modules?
A few decades ago, Saul Walker and his team at Automated Processes Inc. (API) introduced the 500 Series, which has since become one of the most sought-after audio equipment formats on the market. First produced in 1985, the Lunchbox was API’s very first standalone rack. In recent years, the 500 Series has shifted its focus toward modular portable racks rather than console customization.
Today, many other manufacturers create modules that fit the 500 Series specification, which was established in the mid-1980s. Thanks to these third-party designers, the 500 Series has grown into one of the most popular formats available today.
API originally designed the 500 Series as a modular analog format for audio equipment. While its history is somewhat complex, the way it works is actually quite simple. Modules—such as preamplifiers—are inserted into racks that provide power. Each module fits into the same dimensions (5.25″ tall x 1.5″ wide), and multiple modules can be stored in a powered rack.
Depending on your needs, you can place the power rack with its modules on a desk, mount it in a 19-inch rack, or carry it wherever you need to go. Each module in the power rack has both an input and an output, so you can easily connect audio to and from it.
On the rear panel of the chassis, you’ll find the input and output connections where you can begin linking and stereo-linking the signal flow between modules using XLR and TRS jacks. This is where you build your chain of signal processors. You can also easily combine standard rack gear and outboard gear for extra tone-shaping options.
To help you understand the electrical wiring of circuit boards, power specifications, and module sizes for 500 Series equipment, API has released the VPR Alliance specification.
Pros for Using 500 Series Modules
Compact and Portable
Compared to three single-rack-space processors, a 500-series rack takes up three standard rack spaces (5.25″ tall) but can hold up to 11 modules, sometimes even more. Modular 500-series gear is designed to be compact from the start, saving a lot of space compared to traditional rack-mount equipment.
For live setups, smaller “lunchbox” racks are very popular. These racks are built for portability and are easy to carry. They typically hold up to six modules. You can fit up to three modules horizontally in a single rack-space frame. Most modules are 1.5″ wide, but some are double or even triple the width when extra features are needed.
Portability is highly valued in the audio world today. Now you can pack a top-quality mic preamp with phantom power, a vintage-style equalizer, and a great FET compressor into a small lunchbox and take it on the road. This makes it easy to be ready to record multiple sources using just one portable module.
Flexibility
Since the 500 series was introduced, more and more manufacturers have joined the market, and its popularity only continues to grow. Alongside unique devices like reampers and interface modules, there is now a huge selection of 500 series mic preamps, compressors, EQs, channel strips, direct boxes, and effects units to choose from.
This wide variety of options, along with how easy it is to swap and rearrange modules, makes the 500 series format incredibly versatile and adaptable for any engineer or musician. That’s what we mean when we talk about its flexibility.
It’s actually easier to rearrange than a pedalboard. You can fill a three-slot portable rack with your choice of mic preamps, EQs, and compressors, or load a larger chassis with ten identical high-gain mic preamps if you need to record a drum kit or a choir with lots of different microphones.
You’ll also find a wide range of power racks—varying not just in size but also in features and routing options. They’re much more than simple power supplies; many offer convenient patching between modules, dry/wet knobs, LED metering, and more.
Affordability
In addition to its many benefits, the 500 Series is also very reasonably priced. There’s a clear difference between the cost of a 500 Series module and its full-rack-sized equivalent from the same manufacturer. Because the enclosure is smaller, it can be built more quickly and easily.
Another advantage is that the power supply is built into the rack itself, so you don’t need a separate external or internal power supply. Once you invest in the rack and your first couple of modules, the cost per unit drops significantly. This makes the 500 Series a great choice if you want a variety of sound options at a reasonable price.
What’s really interesting about the 500 Series is that you can get a compact chassis that holds up to six modules, and you can swap them out depending on your needs. There’s no need to buy another chassis because it’s so flexible. This is where you really save money—you can spend more on different 500 Series modules instead.
On top of that, there are very affordable, high-end channel strip modules that let you handle several processes in one unit. There are also fantastic and budget-friendly preamp modules and other units that won’t drain your wallet but will still give you amazing sound quality.
DIY Modules
We’re seeing a rise in do-it-yourself kits in the audio community, especially among our more ambitious and budget-conscious members. When you invest your time and effort, you can end up with professional-grade audio equipment that’s worth much more than just the sum of its parts.
These kits offer a range of studio essentials, from simple re-amp boxes and DIs to more complex compressors and audio summing units. Adding a custom module to a 500-series frame—or even repackaging your stompboxes into a 500-series format—is as easy as buying blank panels and connectors, drilling holes for the controls, and attaching a connector.
Besides the satisfaction of building your own gear, you’ll have an audio unit that costs far less than a pre-assembled one. There are several DIY kits that can recreate the famous Pultec EQ for a fraction of the price of the original full rack unit. And it’s not just the Pultec—many other essential modules for a regular signal chain are available as well.
Having Fun
Most people who work in the audio industry got into it because making music is genuinely fun, no matter how long the recording session or how demanding the gig. While digital audio platforms and plugins keep getting better, we believe part of the 500 series gear’s popularity comes from how enjoyable it is to use.
New generations of audio engineers are making music almost entirely with modern DAWs, plugins, and virtual instruments. They’ve been using the power of these tools for years. But newcomers to the industry can really benefit from adding some analog equipment to their studio setups, just like the ‘old guard’ analog tape engineers who quickly adapted their workflows to digital audio.
This hands-on aspect of the 500 series format might outweigh all the other benefits if you’re new to audio, letting you experience the simple joy of turning knobs and hearing what changes for the very first time.
If you’ve ever worked on large-format recording consoles, you know that a rack of 500 series modules gives you a similar feel. For many, that tactile experience of the 500 series format might be the biggest advantage. We think anyone who uses 500 series gear will agree that it’s a lot of fun, and we’re confident they’ll back us up on that.
Conclusion
If you’re searching for high-quality, reliable audio production equipment, the 500 series is an excellent choice. Not only does it offer powerful features, but it’s also priced competitively with similar products. With innovative elements like an intuitive control surface and advanced routing capabilities, 500 series gear is designed to deliver a fantastic user experience.
We truly appreciate the innovation behind 500 series units—they’re an essential part of our production and mixing process, and we use them 100% of the time. We believe that all mixing and recording engineers will share our enthusiasm when it comes to using 500 series equipment.
If you have any questions or need clarification about this topic, please let us know in the comments below. We’d be happy to check your questions and get back to you!
