Resurrecting a MOTU 2408 with ADAT

This is MOTU 2408 MkIII, an audio interface. It's a frustrating thing. It was originally released in 2003, but despite being over twenty years old it's still pretty good. It has eight balanced 1/4" audio inputs, a bunch of ADAT, TDIF, and SPDIF ports, and it records 24-bit audio at 44, 48, 82, and 96khz.

But it's a pain to get working with modern computers. The original MOTU 2408 MkI came out in 1999, slightly before FireWire, at a time when USB was restricted to USB 1.0, so it connected up to contemporary PCs and Macintoshes with a PCI card. What's a PCI card? Ask your parents. They might remember their own parents fiddling around with PCI cards.

The 2408 MkII and MkIII had the same system. To their credit MOTU continued to update the drivers, but as of 2025 the only Apple Macintosh with PCI slots is the Mac Pro, and MOTU's drivers haven't been updated for modern Apple Silicon processors. MOTU's next interface was the 828, but that used Firewire, which is another story entirely.

It would be nice to still use the 2408. And there is hope! Even without a computer connection the 2408 still works as an audio interface. In standalone mode analogue audio that comes in through the 1/4" jacks is routed out to the ADAT, TDIF, and SPDIF ports. SPDIF folds everything down to two-channel stereo, but ADAT and TDIF transmit eight channels of audio at 44 or 48khz, or four channels at 82 and 96khz.

What would be nice is a simple dongle that could pump ADAT to a computer, preferably something cheaper than an entirely new modern audio interface with an ADAT input. There are lots of USB interfaces that output ADAT, but a dearth of interfaces with ADAT inputs.

There is one exception, the MiniDSP MCHStreamer, which is available either as an unclad circuit board or in a little box. I'm not a farmer, so I bought the version that comes in a box. This is what it looks like:

NB I bought it with my own money and have no commercial relationship with MiniDSP. It shipped from Hong Kong and is, as far as I can tell, exempt from UK customs duty, although even if it isn't the price isn't onerous. The boxed version is currently listed at $115, shipping $35, which is about £110. The kit version (which is assembled, it just doesn't have a case) is $10 cheaper. Is it just a Raspberry Pi or something, with special firmware? Could you make one yourself? I have no idea, and possibly, in that order.

The MCHStreamer is essentially a tiny little computer board that converts a bunch of digital audio formats in real time. The boxed version only supports ADAT and SPDIF, although I assume that's only because the internal headers are covered by the case. It's powered by USB, and it's small enough to rest on top of the 2408.

Getting it to work isn't straightforward, although it's still easy. I have a Macintosh. The first step is to download the firmware bundle and plug the MCHStreamer into the computer. At that point you have to upload the correct firmware into the box. In the following screenshot I've picked ADAT:

Step two involves plugging the included optical cable - the package includes two optical cables and a USB cable, which is a nice touch - into the 2408's BANK A optical ADAT output:

Step three involves booting up the 2408 and fiddling with the SELECT and SET buttons. For the SOURCE I picked the audio inputs. Confusingly the LEDs imply that the audio is routed to ADAT BANK C, but no, the audio is output to all three ADAT banks.

For the CLOCK I picked 44khz, internal. Baby steps. I then plugged a radio into input 3, just to see if it worked, and also because I wanted to make sure that it was transmitting on discrete channels and not just 1+2 as a stereo pair.

Then I popped open Audio MIDI Setup and set the MCHStreamer to pick up clock from the 2408's ADAT signal:

Why do you have to do this? If you don't - and I tried it - the signal is crackly. My understanding is that the optical audio protocol isn't like computer networking. It doesn't send packets of data, it just sends a string of bytes, and the receiver has no idea where each byte begins unless it has a clock signal from the source. The result is a kind of audio chaos that sounds awful. Does that sound like a plausible explanation? That's how my mind envisages it. Sometimes my mind plays tricks on me, but deep down there is a brave heart. In my mind.

Synchronising the MCHStreamer to ADAT clock was flaky. At first. I can't tell if it just takes a long time, or if there's a quasi-random factor, but at first it didn't work. After cycling through the 2408's clock options it did eventually hook up, and remained hooked up, although curiously after the first run (pictured above) it only synchronised at 48khz. And yet once it worked, it stayed working. Maybe it's a first-run thing. Perhaps I just didn't have the optical cables plugged in all the way.

After setting all this up I opened Logic, and lo and behold, MCHStreamer ADAT was an input source, with eight channels of audio:

I clicked the input monitoring icon and voila, I could hear a signal coming from the 2408, and I could select each of the eight channels and record audio from them.

As a proof of concept I used it to record the following piece of music, which has a mixture of audio tracks from my modular synthesiser and some virtual instruments:

Sadly one thing missing from this setup is the 2408's original monitoring hardware, which was housed on the PCI card and acted as a mini-mixer.

Still, if you happen to have an ancient MOTU 2408 lying around doing nothing, it can be returned to service as an eight-channel audio interface with a simple ADAT to USB box that powers itself from the USB port. Alternatively, if you want to use the 2408 as a crude mixer you could power the MCHStreamer with a powered USB hub.

In theory you could bypass all of this malarky by plugging the 2408 into the ADAT input of another audio interface. But the cheaper good-quality audio interfaces don't have ADAT ports, and the more expensive interfaces are much more capable than the 2408, so why bother?

If the MCHStreamer was $35 and just a tiny little USB dongle with USB at one end and a pair of optical ports at the other it would be even more superb, although it has to be said that the population of people who have a twenty-year-old MOTU 2408 lurking in a cupboard probably isn't large enough to justify the research and development outlay. If it had a built-in DAC and a 3.5" headphone output it would also be useful for the tiny, tiny population of people who want to use a PlayStation 3 with a computer monitor that doesn't have built-in speakers, but again that's a small constituency. There are dozens of us. Dozens.

Buying a Compact Disc in the Modern Age

I've never been keen on nostalgia, but I'm a broadminded fellow, so in the spirit of discovery I decided to buy a compact disc, in the year 2025, which is this year. I'll show you how I did it.

I'm not suggesting you copy me. What I am about to describe is not for the timid. But perhaps you're curious about physical media, or maybe you bought a lot of compact discs when you were young, and you haven't for a while, and you want to recapture the feeling. Or you want to understand what it was like back in the day, or whatever.

A compact disc in its housing

What is a compact disc? It's a physical data storage medium. A small silver aluminium disc sandwiched between two protective layers of plastic. One side of the disc has a pattern of finely-etched pits, which can be read by a laser and interpreted as digitally-encoded audio. The format was invented by Phillips and Sony in the late 1970s. It was specifically designed for ABBA and Beethoven, but it's also compatible with other musicians. A compact disc can store around seventy-four minutes of 44khz, 16-bit stereo audio. According to the internet the best compact disc is Billy Joel's An Innocent Man.

How many compact discs are there? Lots. They're still manufactured today. They have no practical economic use as anything other than a data storage medium and they cannot be broken down profitably into scrap, but with a few exceptions they remain playable for many years, so there are a lot of functional compact discs still out there in the wild. Most games consoles can play compact discs, with the exception of the modern Sony PlayStation. Standalone compact disc players are still available.

On a legal level purchasing a compact disc grants the owner a licence to play the music stored on the disc in a non-commercial setting. But the discs are un-erasable, the music is not encrypted, and compact disc players were intended to be standalone units that did not connect to the internet, so in practice the buyer "owns" its data.

But which compact disc shall I buy? Discogs.com has 4,980,181 compact discs in its database, and after sifting through every single one I made a shortlist of three. First on the list was the Insane Clown Posse's The Great Milenko. Second was Brian Eno's Ambient 4: On Land. Third was Nusrat Fateh Ali Khan's Mustt Mustt. I eliminated the other 4,980,178 compact discs because they weren't as good.

Unfortunately Ambient 4 seems to be out of print, so I removed that from the shortlist, and I already have two copies of The Great Milenko, so for the purpose of this blog post I ended up with Mustt Mustt. It's an intensely problematic album. iTunes says that the genre is "religious", but that's not true. It's actually world music, released in 1990 on Peter Gabriel's Real World label. Gabriel was one of the masterminds behind world music, and Real World specialised in releasing world music albums.

World music is of course unacceptable nowadays, so after writing this article I popped Mustt Mustt into an envelope and sent it to the Stop Kony campaign. I have no idea what they do nowadays. I enclosed a Post-It note with "please give to a poor child or something" written on it.

Ceci n'est pas une pipe

I'm not going to advertise a particular store. I used Amazon, but there are others. Steam for example. Does Steam sell compact discs? Apparently not, although it did once sell movies and TV shows.

I'm going to digress again at this point. Yes, obviously this blog post is an arch joke. It's not particularly hard to buy a compact disc, even in 2025. Millions are sold every year. And yet it dawned on me that my nearest city doesn't have a compact disc store. Not even the larger newsagents sell compact discs any more. There's CeX, but it only sells DVDs. I'm struggling to think where I might buy a compact disc on the high street nowadays. A larger, out-of-town Tesco? Charity shops? There are a few record stores, but they sell vinyl records, not compact discs.

Even in the heyday of physical stores I would have had to specially order Mustt Mustt, because it wasn't a best-seller when it came out. It sold well, but not in the same league as Lisa Stansfield or Erasure. But, anyway, after selecting Mustt Mustt and putting it in my checkout basket, I realised that I needed to add £25.01 of other things to qualify for free shipping, so I bought two Bosch 12v relays for my motorcycle, some powdered milk, and a bunch of zipties. So that I can ziptie a solar battery tender to one of my panniers. I shouldn't have to justify my purchase of zipties any more.

After finalising my order I gave Amazon my financial details and waited for delivery. I selected a local Post Office as the delivery location, in case I wasn't at home when the compact disc arrived. After two days it was delivered to the Post Office, and I picked it up from there.

After taking the album home I removed it from the packaging, at which point I had successfully bought a compact disc in the year 2025 which is this year. Mission accomplished!

The disc itself. It has world music on it.

I was slightly disappointed to find that the compact disc was packaged in a cardboard sleeve. When I was young compact discs were packaged in plastic cases. Ageless plastic cases that didn't crease or go musty. That was the whole point of compact discs. They were ageless and immortal, not messy or organic.

Packaging a compact disc in a messy, organic cardboard sleeve feels like a retrograde step. I was promised a future of plastic and metal, away from the dirt, and I intend to have that future. Not cardboard. Triangles, aggressive shapes, the smell of burning oil.

I uploaded the CD to my Macintosh, just to see if MacOS could still do that:

Which it does. One day Apple will remove this feature and whatever database iTunes uses for its track listings will be turned off. It has been a long time since Macintoshes had optical drives, but MacOS still has drivers for them - but for how much longer? I've heard tales that Apple Music doesn't actually upload the contents of a compact disc, it instead downloads the files from the internet and replaces the files with updated copies, which can be awkward if there are subtle differences, but as far as I can tell the data of Mustt Mustt on my computer is the actual data from my Mustt Mustt compact disc.

Another example of an album available on compact disc.

It's not iTunes any more, is it? It's Apple Music. Unless you have a Windows PC, in which case iTunes lives on, at least for a while. As the CD-ROM drive whirred into life I thought of all the people who must have uploaded compact discs to their Macintosh, back in the day, en route to their iPod. They called it ripping. The term was devised by software pirates, but Apple made it mainstream because Apple was hip back then.

I've written at length about the different hipness of vintage Apple. When I was very young Apple was hip, but in a different way. It was a different kind of hipness. The company appealed to middle-aged media nerds such as Douglas Adams and Timothy Leary. Apple was the Saab of computers, the Ikea of computers. It didn't target the youth market because its computers cost £6000. And then, in a clever piece of rebranding at the turn of the millennium, Apple said "sayonara" to staid old men and embraced young people, at which point Apple became hip in the modern sense of the word. Hip in the Miseducation of Lauryn Hill sense.

What does it feel like? To own a compact disc in 2025? Partially I felt a sense of emptiness. Until the turn of the millennium a portion of the sale price of every compact disc was sent to Phillips and Sony, who co-developed the technology and held numerous patents on its use. In those days it was heartening to imagine that some of my money was supporting a pair of major global corporations, because corporations rule the world and are better than governments.

But the patents expired twenty years ago, and ever since then Phillips and Sony have struggled, Phillips more than Sony. And the world went to shit as the rats took over.

Partially I felt a sense of melancholia. Compact discs were the future once. Now they are the past. The format isn't even a novelty joke. It's obsolescent, because it still works, and as of 2023 compact discs still outsell vinyl in the UK by almost two to one, but it obviously isn't the future any more.

Compact disc is in the odd position of simultaneously being killed off by the past and the future. The past, because vinyl is more appealing as a collectible, and the future, because streaming media is more convenient. It was eaten from both ends.

In the gap between writing and publishing this article I bought two more compact discs in 2025, which is this year. One was by a band called The Equatorial Stars. The other was by a band called Thursday Afternoon.

If a traveller from the future had told me, as a kid, that vinyl would still be available in the year 2025, I would have said "okay", and "that's actually fairly plausible", and "why 2025 in particular", and I would probably have gestured to my older brother's copy of Jeff Wayne's The War of the Worlds and its awesome booklet, and I would have pointed out that some people might still want to buy Beatles records on vinyl, and there might still be a market for vinyl in the third world, at which point the traveller from the future would have given up. But the point still stands.