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MIDIman M Audio CO3 Digital Switch

With two Z-Systems digital detanglers, two Digital Domain switchers, MIDIman programmable patchbay and a variety of hardware "manual" patch panels my studio should certainly have all the digital flexibility I need. Wrong!

With two Z-Systems digital detanglers, two Digital Domain switchers, MIDIman programmable patchbay and a variety of hardware “manual” patch panels my studio should certainly have all the digital flexibility I need. Wrong!
Product PointsApplications: Switching and distributing digital audio signals

Key Features: Converts between three digital audio input formats; outputs all three simultaneously; versatile SCMS handling provisions.

Price: $249.95

Contact: MIDIman at 800-969-6434.
When the diminutive little silvery box from the M Audio division of MIDIman arrived on my doorstep, it took me less than five minutes to integrate the CO3 into my complex system and it’s not leaving without a fight. Why would such a cute little device, obviously designed for a small studio’s digital needs, find such a willing place in my humongous setup? In a word, flexibility.

The elegant design of this tiny box (roughly 6″ x 4″ x 1.5″) is so clever that one can imagine literally dozens of possible scenarios in which it could be interfaced. And in each one, it would truly make life considerably easier for its owner. The CO3 costs $249.95.

Features/In use

On the front panel, one can select between three digital input formats: AES/EBU (from an XLR on the rear panel), coaxial S/PDIF (from an RCA connector) and TOSlink optical S/PDIF. Press a button and a little LED lights up to show the input selection results. Another LED, labeled Source Valid, lights if the CO3 successfully locked onto the selected input.

The rear panel features the three aforementioned input connectors as well as three more for output. All three outputs are active simultaneously – the chief feature that makes this little box so invaluable. Not only can one select between any of the three flavors of digital source formats commonly found at a modern studio, but the selected input is also automatically converted to the other two formats and appears, along with a “pass thru” (identical) version of itself, simultaneously at all the output jacks.

Consider the possibilities – one can connect up a DAT recorder’s S/PDIF RCA connector digital I/O, a digital workstation’s AES/EBU XLRs, the optical digital output of a CD player and the digital input of an outboard digital to analog converter (such as the M Audio Super DAC 2496), and copy in either direction between the DAT and the DAW or from the CD player to both of them at the same time, and still monitor the input source through your outboard D/A converter.

Here’s another way of thinking about its possible hookup scenarios: one can simultaneously send, copy and monitor any of three different digital input sources, without worrying about which digital format they’re in or the format to which they’re going.

This box does lets one play with the Serial Copy Management System (SCMS) data imbedded in S/PDIF streams. These make it say anything one wants: original, first generation, none or just simply duplicate what the source says.

There have been many times in the past when I’ve tried, unsuccessfully, to get two digital gadgets with different SCMS implementations and expectations to talk to each other. I usually ended up having to run the digital data through my big bucks Lexicon 300L, just to adjust the source’s SCMS parameters – hardly an efficient use of that box! From now on, I’ll just use the CO3 and save the 300L for its normal, intended use.

As usual, MIDIman’s attention to the details of circuit design and parts and build quality were excellent. This accounts for the CO3’s transparent sound (or, lack thereof). There’s also a built-in jitter reduction circuit that effectively reclocks the input signal for greater stability in the time domain further down the chain.

Another professional feature of the CO3 is that, with the exception of the S/PDIF coax input, all its inputs and outputs are transformer or optically isolated. This allows devices to be plugged into and unplugged from the CO3 while its power is on. The box could even be connected permanently to a digital patchbay, which would permit different sources and destinations to be easily connected at will to the device (as scenes), and still have the flexibility to have certain critical functions switched from its front panel.


I cannot imagine a studio – of any size – which could not put this little box to good use. I’ll use it to double the switched input capacity of my Wadia DAC while simultaneously allowing easy connection, interconnection and monitoring of the various digital devices needed to temporarily connect into my studio when reviewing products for PAR.

The box’s small size makes it possible for me to nestle it in a tiny space among the various pieces of equipment perched upon my keyboard stand and keep it within arm’s reach. Thanks again, MIDIman – oops, M Audio, for another invaluable little gizmo.