Top 10 500 Series Chassis: Tested Home For Your 500 Modules!

Top 10 500 Series Chassis


With the rising recognition of 500 series gear, a handful of firms are actually additionally producing their very own variations of 500 series racks.

As companies attempt to compete with one another for market share, we now see many variations of those cases, every with its pros and cons. A few of these embody things like link switches, stereo compatibility, and additional routing selections for the producers who prefer to get proper modular with their summing and routing.

We’re principally spoilt for selection now, and it could get somewhat complicated as to where to start when selecting the right 500-collection chassis for your studio.

History of 500 Series Modules

The 500‑series format was invented by API founder Saul Walker in 1968 and it shaped the idea of his console designs. The primary standalone racks have been most likely DIY ones, however, in 1978 Datatronix (who made API products when API had ceased manufacturing for a time) manufactured a 10‑slot rack.

Aphex additionally tailored a rack intended for their very own modules so it could host API ones. The 500 series was removed from the only modular system at the time, and it remained an area of interest till the 1980s when that notion of a ‘lunchbox’ (it was an Aphex rack that was first known as this, that means a portable, modular recording channel comprising 500‑series models) gained traction with freelance engineers working throughout different studios. API has been making two, six, and 10‑slot 500‑series chassis since 1985 and owns the Lunchbox trademark.

What are 500 Series Modules?

The term ‘lunchbox’ is thrown across the industry, to the confusion of many. These in the know are conscious that it isn’t truly a case for your sandwiches, however reasonably a revolution within the audio business’s interaction with rack unit gear. Believe it or not, now turned out to be an extensively common modular analog format for rack gear.

On a really basic level, individual modules (similar to an EQ) are inserted right into a rack that provides energy to the modules. Every case is constructed to carry various models (modules), and apart from powering up the modules, the case additionally supplies input and output routing to every unit. So these 500 series models are enclosed in a chassis, so let’s examine precisely what that is.

500 Series Enclosure Fundamentals

500 collection modules are housed in a powered enclosure, typically known as a chassis, rack, or lunchbox.

Chassis and racks are designed to be rack-mounted, whereas a lunchbox is designed to be transportable (its look and carrying handle remind of a lunchbox.)

The enclosure serves a few functions:

  • It provides energy to all modules, together with 48V phantom power.
  • It provides connectivity to all modules via XLR, ¼ ”, and/or DB-25 inputs and outputs
  • It provides safe housing to guard modules against damage
  • Some enclosures additionally present stereo linking or audio summing capabilities.

What to Look For In A 500-Sequence Enclosure

Crucial things to search for in an enclosure are:

  • Compatibility
  • Lots of connectivity
  • Plenty of power
  • Compatibility with older 500 series modules

We just want to let you know that we’ll list these 500 Series Chassis in no particular order. They’ll be randomized as we don’t wish to sort them from best to worst.

Listed below are our Top 10 Best 500 Series Chassis for 2023:

1. Rupert Neve Designs R6

With considerable power and versatile connections, the R6 delivers peace of mind for engineers who demand the next degree of confidence in their 500 series racks.

Power-wise, the R6 has more than double the required current for a 6-space chassis to stop the power rails from failing beneath a higher-than-expected load. To assist monitor and troubleshooting problematic modules, the R6 is provided with LED current metering to indicate how much energy is getting used.

The interior power supply itself has been fastidiously designed and double-shielded to keep away from important magnetic induction in any of the channel positions. With such consideration to offering and monitoring power, the R6 helps your modules give their fullest potential.

With a plethora of connections out there, the R6 back panel is virtually a patch bay by itself. The R6 features 8 channels of balanced I/O choices together with DB-25, XLR, and TRS that could be used interchangeably. This versatility is very helpful if you end up taking the R6 with you to a different setting where you might be unsure of the cables out there, or if you have to convert DB-25, XLR, or TRS connections to a different format utilizing the THRU performance on channels 7-8.

The chassis is comprised of strong metal with bumpers to help the unit in each horizontal and vertical configuration and encompasses a collapsible handle for portability. All connectors and fittings are of the best quality to make sure that the R6 will maintain up to many years of use.

Rupert Neve Designs R6

  • 3 Link jumpers can be set to allow linking on channels 1-2, 3-4 and 5-6
  • Solid steel chassis
  • Dimensions (L x W x H): 330 x 190 x 139 mm
  • Weight: 4.31 kg

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Rupert Neve Designs R6

2. Cranborne Audio 500R8

Its many roles embody USB audio interface, monitor controller, 500 Series rack, and summing amplifier. However, rather than being a jack of all trades, master of none, it does every little thing very well. Regardless of such broad performance, it’s surprisingly user-friendly and intuitive, not to point out reasonably priced.

The 500R8 is a 4RU unit contained in a sturdy metallic casing. It comes with rack ears that may be detached and become a carrying handle.

The overwhelming majority of its front panel space is open so that you could populate it with up to eight 500 Series processors. The inventory 500R8 doesn’t include any built-in preamps—besides one for the talkback circuit.

Populating your 500R8 with 500 Series items will clearly add to your complete value, however, you don’t have to do it all at once. Even for those who only fill a few slots initially, you’ll be able to configure every of the eight analog input channels to just accept line-level signals, making it potential to connect exterior preamps so long as they have line outputs.

Finally, if you wish to get probably the most from the unit, you’d fill it with quite a lot of preamp types, and swap out and in compressors and EQs as needed, too.

Cranborne Audio 500R8

  • Monitor controller
  • 8 Channel discrete analogue summing mixer
  • Reference AD/DA converter
  • Latency-free monitor mixer with volume and pan controls per channel
  • 2 Monitor outputs: Speaker A outs & Speaker B outs

Cranborne Audio 500R8
  • 8 I/O channels with XLR
  • USB audio interface with 28 in / 30 out

3. IGS Audio Panzer 500

The Panzer 500 chassis is as no-nonsense as well. The metal enclosure is a rackmount design and houses a circuit board with the EDAC connectors required to accommodate as many as 10 modules. (Not bad for 3U of ordinary 19-inch rack space)

On the far right, there is a one-module-wide panel that is a host to a few LEDs that point out the presence or otherwise of energy on the ±16V rails and the +48V phantom supply.  Power itself is delivered through a compact however rugged exterior unit with its own carry handle, and an average of 420mA is offered per module slot. 

That is firmly connected to the chassis via a cable with super-chunky screw-threaded metallic connectors, which is sweet. The IEC lead goes in a single end, the chassis’ power cable out the other, and a robust-feeling toggle switch permits the juice to move.

The audio I/O is introduced on the rear of the chassis as 10 individual XLRs for the inputs and another 10 for the outputs, with the pin hot/cold wiring, clearly labeled. It could not seem easier, and in tests, it worked without problem utilizing the IGS modules and all the different modules we examined.

All in all, then, it is a respectable modular system for the cash, and the truth that IGS appears to be adding extra to the range can solely be a good factor. For us, although, the star of the present is the Panzer 500 chassis and energy supply, which provides a large amount of 500-series real estate for the cash and makes it simple to mix the 500 series and 19-inch rackmount items in a wise way.

IGS Audio Panzer 500

  • Predominantly use stepped switch controls.
  • Up to 10 processors in a 3U rack space.
  • New modules being added to the range.
  • Large LED meters.

IGS Audio Panzer 500
  • Fully compatible with all 500’s modules
  • Power supply to 420 mA per slot

4. Heritage Audio OST-4 V2

Home all of your prized 500 Series gear within the Heritage Audio OS-4 v2.0 Chassis, a high-quality 500 Series rack with 4 slots. This enclosure can deal with double-wide modules, in addition to power-hungry Class-A and vacuum tube designs. With Heritage Audio’s On Slot Technology, the OS-4 v2.0 ensures that every channel gives a high degree of safety, isolation, and filtering.

Every rail slot gives 400mA of current, for a total of 1.6A. Up to 140mA of phantom power may be equipped. Each of the slots on this rack basically has its personal energy supply, one that’s regulated individually and isolated from the others. This ensures that no power-hungry unit will wreck the constancy of one another.

Heritage Audio additionally assures you that many 500 Series items will carry out better when housed within the OS-4 v.20. You must note, and be capable to measure, a lower degree of self-noise in 500 Series preamps, for instance.

On the rear of the unit, you will find 4 XLR inputs and 4 XLR outputs, in addition to a five-pin XLR power input jack. All XLR jacks are gold-plated. A serious addition to this collection of rack enclosures is the link characteristic, which routinely feeds one channel into the following on the panel with the push of a button. Now, you do not want to make use of patch cables if you’re outputting signals in series. Merely press the link button between two slots, and one will routinely feed the other.

Heritage Audio OST-4 V2

  • Power supply with 400 mA per rack
  • Phantom power supply (140 mA max. total demand)
  • External power supply unit
  • XLR connections

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Heritage Audio OST-4 V2
  • Design: 500 module series, 3U
  • Weight: 1 kg

5. API Audio 500-8P Lunchbox

From the inventors of the 500-series format, the API 500-8B lunchbox is an 8-slot, 500-series energy rack designed to just accept all API normal 5.25″ X 1.5″ modules, permitting you to configure a recording or mixing package to fit your particular needs.

The big brother to the API 500-6B, the API 500-8B lunchbox makes use of the included common power supply with a rear-panel selected AC voltage swap and a detachable energy cord. The input/output jacks are DB-25 (D-Sub) connectors for simple I/O. The API 500-8B lunchbox comes customary with a +48 volt inside the phantom power supply, bussed to pin 15 for interface with the API 512c Mic Preamplifier.

The older 560A equalizer might use pin 15 for a “direct output” and should be disabled on the 560A circuit board edge connector by cutting a trace. It will eradicate 48 volts from damaging the 560A series equalizers.

The rear panel of the 500-8B lunchbox has two 8-channel connectors for input and output. There may be additionally a power connector and AC power selector swap for international use.

The lunchbox offers an engineer the flexibility to carry along specialized EQ effects to any scenario: 550A, 550b, or 560. The lunchbox is self-powered. API makes a number of modules for the 500 series, such as the 512c Mic Preamplifier, the 525 Compressor, the 527 Compressor, the 550A 3-band EQ, the 550b 4-band EQ, and the 560 Graphic EQ. Combos of those modules make good stereo recording packages (two 512Cs and two 550Cs) or a vocalist’s boxes (one 512c, two EQs, and one 527).

API Audio 500-8P Lunchbox

  • Integrated power supply from 100 – 250 Volt switchable
  • Rugged steel housing
  • Rubber feet and carrying handle
  • 19″ Rack kit optional (not included, available under Art.

API Audio 500-8P Lunchbox
  • 250 mA per slot
  • Internal 48V phantom power

6. Fredenstein Bento 8 Pure Analog

Just like most 500 chassis, the Bento 8 is a 3-rack space unit, and contains feet (for desktop use) and rack ears – which wins critical factors from us because we don’t have to purchase them individually if we decide to rack it up. All I/O is XLR.

This was effective, however, but some would possibly want a chassis with DB 25 and/or 1/4-inch TRS connectivity. It has a power change, which is nice, but it surely’s on the back so might be of restricted use in a rack. Very useful is the fact that a built-in linear power supply means it plugs in with an IEC cable – no exterior power supplies to get misplaced within the sea of cables behind your rack.

Even preamps plugged instantly next to the power supply had been noise-free, because of what Fredenstein describes as “in-depth magnetic shielding” across the mains transformer. If that’s not sufficient, the Bento 8 additionally incorporates a ground-lift switch, although the manual properly suggests avoiding this feature if at all possible.

The specs boast 500 mA per slot, which was more than enough to power the whole lot. We were additionally delighted to see that this factor is sturdy and well-constructed, it’s heavier than we expected, feels stable all around, and options countersunk fasteners so that you simply don’t scrape your other rack gear.

Fredenstein Bento 8 Pure Analog

  • Compressor link and ground lift switch
  • Intelligent voltage distribution
  • Energy efficient
  • Design: 19″ / 3U

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Fredenstein Bento 8 Pure Analog
  • With analogue power supply +/- 16 Volt / +48 Volt
  • 500 mA per slot

7. Radial Engineering Workhorse SixPack

Let’s begin with the back. As you’d count on, there are XLR jacks for six channels of I/O. If you wish to use the SixPack like some other 500-series body, connect your cabling to the XLRs, plug within the exterior power supply, and you’re ready to go. However, then you will definitely miss out on all of the fun!

Between odd and even slot pairs within the back are Link switches. These let you “link” adjoining pairs of modules that assist link performance for stereo processing, no need to maneuver internal jumpers or solder throughout points on the SixPack’s backplane.

Between all of the slots are feed switches. These let you simply tie module outputs to the inputs of the next modules up, without utilizing patch cables, to shortly chain a number of modules into “channel strips.” For instance, you’ll be able to “feed” a mic preamp in slot 1 to an EQ in slot 2, then to a compressor in slot 3, simply by enabling the appropriate feed switches.

The input of your channel strip would then be the input of slot 1, and the output would be the output of slot 3. In the meantime, if you needed to additionally record the pre-compressed signal (for parallel processing or for safety), you would take the output of slot 2 and patch that into your recording device. These Link and Feed switches are signature options of the entire Radial Engineering Workhorse line.

Radial Engineering Workhorse SixPack

  • For system 500 modules
  • Per input channel input (XLR and jack), output (XLR and jack)
  • Switchable 48 V phantom power

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Radial Engineering Workhorse SixPack
  • External power supply
  • Metal grip

8. Midas Legend L10

The Legend L10 500 Series Rackmount Chassis allows you to mix and match a variety of audio processing modules to construct the best signal chain for any application. With space for as many as 10 single-width modules, superior audio routing for simplified cabling, and a strong auto-ranging common switch-mode power supply, you may take your favorite modules anyplace with full confidence.

Designed to accommodate all 500 series-compatible modules and plug-in cards, the L10 is the right companion for your Microphone Preamplifier 502, Compressor Limiter 522, Parametric Equaliser 512, and the various different modules at present under development – in addition to these from 3rd party distributors.

Whether or not you might be in the studio or on the street, signal chain cabling no longer needs to be a difficulty. L10’s audio output link switches make it simple to rearrange and connect your modules without the necessity for advanced cabling. Simply set up your modules in the order you would like and cross the signal along the chain free of any extraneous cables. This not only makes your rack a lot neater, but it surely additionally helps you preserve the ultimate signal integrity.

Because of the onboard ground lift swap, you may simply lift the audio ground and get rid of annoying ground loop issues that may in any other case spoil an ideal performance.

Midas Legend L10

  • Width: 448.31 mm
  • Height (without feet): 132.40 mm
  • Height (with feet): 139.50 mm
  • Depth: 210.63 mm

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Midas Legend L10

9. Lindell Audio 510 Power MKII

We might suggest the Lindell Audio 510 Power MkII ten-slot chassis and power supply to anybody on the lookout for a rackmount 500-series frame. It has a number of options that make it very useful and versatile.

Firstly, it has both XLR and DB25 connectors (wired in parallel) for the primary eight slots. This makes connecting to a patch bay equipped with DB25 connectors a lot simpler and extra affordable. We additionally really like this characteristic because it makes the rack very easy to interface to most multichannel converters in the event you’re doing a remote recording, which is one of our primary uses for 500-series gear.

Secondly, it has feed switches between slots, so you’ll be able to tie the output of a mic preamp in slot 1 to the input of an EQ in slot two without utilizing cables, for example. That is one other nice characteristic for doing remote recordings because it permits you to successfully construct channel strips inside the rack.

Thirdly, in contrast to all the different 500-series frames, this has a sturdy, metal-boxed, exterior power supply instead of an outsized line lump that may ultimately fail when its cabling has an excessive amount of strain placed on it, one thing that happens quite a bit on distant gigs.

The Lindell provides a normal IEC input jack for AC power (100–250 V, 50/60 Hz), and an XLR5 output for DC power to the body. Due to this fact, each cable might be disconnected from the power supply and is simply replaced if there may be ever a failure. The power supply can deliver most of 5 A, and in case your modules collectively draw too much current, a safety circuit steps in and shuts the power supply down.

Lindell Audio 510 Power MKII

  • External universal power supply unit 100-250 V
  • Short circuit and overload protection
  • Light aluminium housing
  • Includes 19″ rack adapter and blanking plate

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Lindell Audio 510 Power MKII

10. Black Lion Audio PBR-8 500

The folks at Black Lion Audio had a thought that actually sets their new Patchbay Rack 8 (PBR-8) aside from most, if not all, different 500 Series enclosures; they’ve built in a TT patch bay for all eight channels’ inputs and outputs on the entrance panel of the chassis and in addition included two units of multi (one in and two outs).

Black Lion teamed up with Heritage Audio in Spain to construct the PBR-8, benefiting from Heritage’s OST (On Slot Technology), which offers power regulation per slot to scale back noise and crosstalk. On the chassis’ back panel every channel has an XLR input and output, however, there are additional DB-25 jacks to wire all eight channels on a single cable – useful in case you’re hooking up to a patch bay with DB-25 connectors. An exterior “lump-in-the-middle” style power supply feeds the PBR-8 through a locking multi-pin connector.

Imagine you are touring to a different studio and also you need to bring a bunch of gear of your own to plumb into the studio’s tools. Within the PBR-8, for instance, you can have six slots crammed with a pair of preamps, a pair of EQs, and a pair of compressors (basically a few channel strips), after which put a stereo bus compressor within the final two slots.

Now, think about being able to change the order of the channels (EQ pre-compression or after, and even the outputs of each channel strips into the bus compressor) without having to reach behind the rack to move cables around, chain outputs to inputs, or trouble with the studio’s own patch bay. These situations play out brilliantly and are all attainable through the front panel of the PBR-8.

Black Lion Audio PBR-8 500

  • Integrated balanced TT / Bantam Patchbay
  • 2 Multiples / Signal splitter
  • ‘On Slot Technology’ by Heritage Audio
  • Up to 400 mA available per slot
  • Solid steel housing

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Black Lion Audio PBR-8 500


We believe that any of these ten 500 series chassis will do the job properly and you will have no problems with them. Also, you can decide from the short review we provided for any of them what will suit you best.

Also, we didn’t select the chassis by the slot amount, but by functionality and popularity. You will be able to find from 2,3 slots up to 10 slots – and maybe even more.

If you think that we missed something important in this article, please let us know in the comment section and we will get back to you and update the content!

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Nikoloski is the founder and main content writer and editor of Mixing Tips. With his experience in audio engineering, mixing, and mastering for over 15 years, will provide hands-on experience and expertise in all the matters covered on this website.

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