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Cranborne Audio 500ADAT

ADAT Expander, Analogue Mixer & 500-series Rack By Matt Houghton
Published November 2019

Cranborne Audio 500ADAT

Can Cranborne convert you to the 500 series?

As I said when reviewing their superb 500R8 USB audio interface (, it was actually Cranborne's 500ADAT which first piqued my interest — I've been suggesting to manufacturers for years that they should make a 500-series rack with onboard ADAT converters, since lots of us have interfaces with ADAT ports sitting unused. And though the 500ADAT wasn't the first such device to be announced, it is the first to become available.


One or more 500ADAT units can be linked to a 500R8 to form a larger 500-series USB interface system, in which configuration the 500ADAT's capability is slightly extended. But it's also intended for use with other manufacturers' interfaces; Cranborne rightly recognise that many people are very happy with their current audio interface, and that others may require an interface to tick boxes the 500R8 can't (eg. a Universal Audio device with 'Unison' preamp emulations, or something that offers more or different I/O). In short, if your interface has ADAT ports the 500ADAT can be used to add 500-series hosting, with A-D/D-A conversion at all the usual rates at up to 192kHz (courtesy of SMUX II and IV).

For example, until recently I owned an RME Fireface 800 interface, with dual SMUX-compatible ADAT ins and outs. That device could support two 500ADATs — so, 16 channels of 500-series preamps/processors — at base sample rates, and still leave the interface's analogue and S/PDIF I/O available for other duties. Only four inexpensive 'lightpipe' fibre-optic cables would be required to plumb it all together (though if you preferred, you could use wordclock to sync things). Alternatively, connected to one 500ADAT via both ADAT ports, it could support eight channels at up to 96kHz, or four at up to 192kHz.


Other than its lack of USB interfacing, the 500ADAT varies very little from the 500R8. The converters are identical, and feature the same reference-grade, ultra-low jitter master clock. And on the analogue side, as with the 500R8, no 500-series modules are required to use this thing as a line-level converter; each slot has a switch near the edge connector to bypass the module and deliver the analogue input to the converters or the analogue summing mixer.

The mixer's controls are arranged beneath the module slots. For each channel, a toggle switch selects the input source for each channel (the choices are the CAST input, of which more shortly, the line in/500-series out, and the ADAT input) and there's one rotary knob for level and another for pan.

On the right are controls for two stereo 'aux' busses. Each aux bus has a knob to blend between the mixer's stereo bus and the rear-panel aux input (or a 'CAST Link' signal from a 500R8). Another knob adjusts the output level, and the aux bus signal goes to one of two front-panel headphone outputs (via an impressively powerful headphone amp!) and to the corresponding aux output on the rear. A backlit on/off button completes the front-panel controls.

CAST is a means of carrying four channels of analogue audio up to 100m using a CAT5e cable. It's a refreshingly simple way to receive signals from and distribute them to artists — no need for bulky analogue cables, or to invest in a networked digital audio system. Cranborne already make a couple of devices that can connect to the 500R8/ADAT in this way, and more could follow. CAST Link works in the same way to combine the 500ADAT and R8's mixers and cue-mix facilities.

The rear panel hosts all the I/O except the headphone outs, and includes RJ45 sockets for Cranborne's clever CAST system.The rear panel hosts all the I/O except the headphone outs, and includes RJ45 sockets for Cranborne's clever CAST system.

The rear panel sports various I/O. Four RJ45 sockets cater for CAST (one in and one out for channels 1-4 and 5-8), and a fifth for CAST Link. Each channel has balanced XLR inputs and outputs, and a TRS jack insert point (post the 500-series module, with the return signal delivered to that slot's output, to the mixer, and to the converter). Wordclock is on the usual BNC connectors, and power is via an external inline 24V DC supply. The 500R8's speaker outputs are gone, replaced with the second aux bus's output, and gone too are the S/PDIF connectors, the talkback mic input and MIDI I/O. There is a USB port that caters for firmware updates (but not interfacing). Finally, an array of DIP switches allows you to set the 500ADAT to operate as the master and to set the sample rate, or to slave to either the ADAT or Wordclock input. (Cranborne recommend you make the 500ADAT the master where possible).

On Test

I recently replaced my Fireface 800 with an RME MADIFace USB and used this during the review period, connecting the 500ADAT to a Ferrofish A16 Ultra MkII, which in turn connected to the MADIFace via MADI. Once I'd set up the routing on the Ferrofish, connecting and synchronising the 500ADAT was as pain-free as ADAT always is, and it worked at all the advertised sample rates.

I have little to add that I've not written about previously in the 500R8 review, which is a positive thing! It's all very easy to use and it sounds top-notch. Set up to work as a line-level converter, it sounds just as crisp and clean as the impressive specs suggest it should and how I recall the 500R8 sounding. I didn't have the opportunity to measure the performance this time, but I've no reason to suspect the results would differ from those for the 500R8; it's the same technology implemented in much the same way, and the same specifications are quoted in the manual.

It sounds just as crisp and clean as the impressive specs suggest it should.

Used as a 500-series host, I packed it full of various modules (including a couple that are a tad power-hungry and haven't played nicely with some cheaper racks) and it always performed flawlessly. And while it might offer more functionality when paired with a 500R8, I could still use the onboard mixer and aux controls to create cue mixes, with the backing track coming from the DAW either via analogue connections to the aux 1 input, or via ADAT and thence to the mixer. I can't say I missed the talkback facility of the 500R8, though some might.

One minor criticism is that changing the sample rate and clock settings is a little fiddly, particularly if the unit is rackmounted. But Cranborne tell me they have plans to add some USB control functionality "in the future" and, of course, for many people this stuff will be a case of set-and-forget.


Although more expensive than a 'no frills' eight-slot 500-series rack, the 500ADAT offers you more. To get close to a comparable system, you'd need to budget for a decent stand-alone bidirectional converter (the 500ADAT is no slouch in this department), an eight-slot rack and a summing mixer — or a converter and Heritage Audio's eight-slot 500-series rack (which has a summing mixer built in). You still wouldn't have all the features of the 500ADAT, and it would cost much more, even before you factor in the necessary cables. So really, the 500ADAT isn't at all expensive for what's on offer.

In short, in the 500ADAT Cranborne have again delivered remarkable quality at a truly competitive price, while also plugging a long-standing gap in the market. So if you're keen on the 500 series and have ADAT ports standing idle, why not put them to good use and give this a go?


  • Same converters and impressive technical specs as the 500R8.
  • Includes both analogue summing mixer and analogue cue-mix facilities.
  • CAST system is a really good idea.
  • Operates as a line-level converter even without 500-series modules.


  • None.


Cranborne's 500ADAT sounds great, boasts useful facilities, and makes adding 500-series processors to your existing audio interface convenient and hassle-free. You get a lot for your money too!


£1399 including VAT.

Sound Technology +44 (0)1462 480000


Cranborne Audio +44 1707 656500.