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Magma CB2S

2-slot PCI Expansion Chassis By Paul Wiffen
Published January 2001

Magma CB2S

Magma's ingenious PCI Expansion Chasses attach to portable computers via PCMCIA and allow you to run PCI audio, video and SCSI cards. Paul Wiffen tries out the latest model, which works with current Apple Powerbooks as well as PC portables.

My spine is deeply indebted to Magma. In the past, for my demonstrations, lecturing and programming sessions I used to lug around a 266MHz tower‑format G3 computer to house my PCI audio and video expansion cards (and, of course, a very heavy SVGA monitor to go with it). This didn't seem out of place in the greater scheme of things as I was also lugging around a Korg Trinity, Z1 and 168RC mixer (I was working for Korg as a product specialist at the time). All that constant lifting in and out of cars was really beginning to take its toll on my back. Things got a little better when the TR‑Rack came out, but there were still plenty of heavy items going in and out of the car. It never really occurred to me that there was any alternative to all this lifting, except possibly by expanding the budget to be able to accomodate a roadie.

At the beginning of last year, I bought a 300MHz Apple Powerbook (of the series code‑named Wall Street), primarily for everyday tasks like writing, Internet access and DTP. But as I began to get more and more involved with soft synths and samplers, I realised that I could replace the heavy keyboards with physical modelling and software sample playback. The problem was that I only had the Powerbook's onboard audio capabilities to record and play everything back through.

Now, in recent years the D‑A converters on Macs have improved steadily, and I found the quality of output perfectly acceptable. I have never really had a problem with mini‑jack connectors either. But I am afraid I cannot get used to mixing on a computer screen with a mouse. When a sound comes in too loud in a demonstration to a couple of hundred people through a PA, you need to be able to grab a fader and drag it down in an instant, before everyone's ears start bleeding. The one item of Korg gear I wasn't prepared to do without, even though I no longer worked for Korg, was the 168RC mixer.

However, an external hardware mixer is no use to you if you can only get two channels out of your computer. How are you going to alter the respective levels of the different sounds if they are not coming out of your computer on different channels? I did the rounds of all the ADAT optical card manufacturers I knew, asking when any of them were going to produce an ADAT optical‑equipped PCMCIA card. The responses were not encouraging, and two years later there is still no sign of such a card.

I set about looking for other ways of getting separate audio outs. Imagine my joy when, at MacWorld in San Fransisco, I saw the original Magma PCI expansion chassis, which connected via the Apple Expansion Bay. I made contact with Magma and arranged to try it out with the Sonorus StudI/O ADAT optical PCI card (which I had just started to distribute) at the NAMM show a few weeks later. There were some tense moments on the Sonorus booth as we hooked up the industrial‑strength ribbon cable to the chassis and powered up, but once everything was in place, there was great rejoicing when all 16 channels of my demo piece flowed into the Korg 168RC for the first time from my Powerbook. Things got even better when the accompanying video was output to a big display via my trusty Miro Motion DC20. I got my credit card out there and then and returned to England with the rather dull beige box in my suitcase. My back hasn't given me a twinge since.

Everything Under The Sun

In the 18 months since then, I have had most of the available ADAT optical PCI cards in the back of my Magma chassis (I'm starting to sound like a taxi driver now) — Korg 1212 and OASYS, RME Hammerfall (which is so small it can actually be fitted into an unpublicised third slot in my unit), Frontier Dakota and Montana — and all of them have worked fine. I have installed numerous systems based around this chassis and they are all working very well. I have even used two Sonorus cards and/or the Dakota/Montana combination at the same time, and had 32 channels outputting perfectly through a Yamaha O2R or Mackie d8b desk. The only card I have had trouble with in the chassis is the Frontier WaveCenter PCI (apparently PLX9050‑based cards like WaveCenter PCI are registered in the MacOS as video cards). Although I have never used MOTU's PCI products in my own chassis, I talk to enough MOTU users who do to be confident that they work fine as well. Rumour also has it that although this particular chassis is not approved by Digidesign (a lengthy procedure which several of the seven‑ and 13‑slot Magma chasses have achieved), people are using it for their systems as well, although having only two slots would limit you to a Digi 001 or a small Mix Plus system.

The newer series of Powerbooks (the Lombard) which came out last summer changed the size and shape of the expansion bay, so the model of PCI chassis I have cannot be used on them. Magma reacted by switching their design to connect via the PCMCIA slot, and had great success on the PC platform. However, there was a problem with the PCMCIA slot on the Lombards which meant that the interface for this new chassis still wouldn't work. By the time the hardware fix was found, Apple had started shipping the third generation of G3 Powerbooks (codename Pismo), so they incorporated the fix into that series. Unfortunately, this does rather leave Lombard owners out in the cold as far as PCI expansion is concerned! However, Pismo owners are now able to benefit from the same PCI expansion capability that I enjoy, in the form of the new PCMCIA‑connecting version of the chassis, and from further decreased size and weight into the bargain.

Cosmetic Upgrade

The first thing that you notice when you get the new Magma out of its packing is how much better it looks than the original. The transition from beige anonymity to smartly‑logoed black sleekness is a marked improvement. The new unit is only slightly longer and fractionally wider than the Powerbook itself, which means that the computer sits beautifully on top of it. The 30 percent reduction in size and weight from the unit I have will be very welcome when shifting it around.

The lid (secured by two screws) which needs to be removed to install the PCI cards was a bit of a tight fit on the unit supplied, and a little brute force and ignorance was required to make it slide the necessary half an inch back before it lifts off. I guess that regular opening or a little grease would soon sort this out. Installing cards is a breeze, with the traditional locking screw holding them in place (this is doubly advisable if you are going to be moving the unit about a lot). The CB2S supplied for review has an ATTO Express PCI Ultra2 SCSI card adaptor as well as the two PCI slots, together with the necessary power and ribbon cables to allow a large‑capacity 3.5‑inch audio drive to be fitted. Normally, your dealer would source an appropriate drive (SCSI 1, SCSI 2, SCSI 3 and Ultra 2 models are compatible) and install it for you, but the necessary driver software is also supplied if you want to tackle this yourself. Unfortunately, I couldn't lay my hands on a suitable bare drive within the time frame of the review, but I will try to do so in time for next month's Apple Notes.

Once the PCI card(s) of your choice are installed and the lid back on, it's time to connect the chassis to the PCMCIA card. This is done using a very solid‑looking cable with miniature connectors (there is not a lot of room on the exposed end of a PCMCIA card). The same connector is used at both ends, and there are locking nuts to make sure you don't get disconnected. The only problem is that on the version with the SCSI card as well, an additional connector of the same type is provided to allow additional SCSI drives to be used — but there is absolutely no labelling to say which is which, and no explanation in the manual! I don't suppose it would do any damage if you connected these the wrong way round but it would be nice to see a label and/or instructions in the manual. As it is, you can only tell by taking the lid off.

Having surmounted this hurdle, I inserted the PCMCIA card in the side of the Powerbook (the thickness of the cable makes the required 90‑degree twist a little hard going) and powered up the chassis. The two cards I had put in (the Sonorus StudI/O and the RME Hammerfall) were recognised immediately by their ASIO drivers, which I had pre‑installed in both Cubase and Logic, without the need for a reboot. Hot‑swappability is truly a wonderful thing. This means you could be using your computer for other things, decide to do some digital audio, plug in the PCMCIA connector and launch the application. No more tedious mucking about with endless reboots to get PCI devices to be recognised. Of course, it only works for those cards which do not need to be booted from an extension first; the Korg OASYS, which I tried next, did require a system reboot. In fairness, though, this works outside its ASIO drivers with a stand‑alone application for modelling sounds, so this is to be expected. Neither the Sonorus nor the RME card interacts with anything but ASIO or direct program control from Logic.

All of these cards behaved normally when recording, and within seconds I had forgotten that I was running the cards not on a desktop computer but a laptop. I also tried playing back some serious multichannel audio with 16 outs on both the Sonorus and the RME, and didn't run into any problems. Obviously, I didn't have access to all the different PCI cards one might try to use, but I am happy to report that my Miro DC20 was also happy playing back a full 30‑frame NTSC QuickTime movie whilst the audio card was outputting 16 tracks. This is pretty much the maximum amount of data transfer that I could generate through the chassis, and it seemed to work flawlessly.


On the functional side, there is little more to say about the CB2S other than that it works perfectly, to a very high level of data throughput, at least with the cards I tested. Setting up is a breeze, in that there is no additional software to install (unless you are using the SCSI option, which requires the supplied ATTO driver to be installed). Provided that you are not trying to use a full Pro Tools Mix Plus system — in which case you could always go for one of Magma's larger models — this unit will bring your Powerbook into the same league for music and audio as a desktop or tower unit. The ability to add a fast, high‑capacity drive within the chassis is a real boon, making it the perfect solution for the musician or engineer on the move. Obviously, it's a shame that it doesn't work with earlier Powerbooks (I tried it on my Wall Street and it definitely is incompatible — same PCMCIA problem as the Lombard, I guess), but this is hardly Magma's fault. If you have been delaying buying a Powerbook until you can get real multi‑channel audio access, or if you already have a Pismo (or PCMCIA‑equipped PC) then this is the unit for you.

On the financial side, some people have a conceptual problem with paying more than the price of their PCI card for a chassis to put it in, but I can testify from personal experience what a liberating option it is, allowing the mobile user to drastically reduce the weight of the kit he or she has to carry around. The CB2 easily justifies its price by the absence of lower back pain, and the additional cost of the CB2S is little more than you would pay for a SCSI card inside your computer plus the power lines and connectors to run drives from it.

Thanks to Steve Fairclough of OM for making his Pismo available to me to test the chassis.

Powerbook Compatibility

Magma offer the following compatibility information for audio PCI cards, Powerbooks and the relevant designs of PCI Expansion Chassis on their site:

CARDWall Street PowerbookPismo PowerbookNOTES
Emagic Audiowerk8YNot tested'Customer results' — not tested by Magma themselves
Korg 1212YYRequires Korg driver rev 1.3; will not work with a SCSI controller card in chassis
Korg OASYSYYAs above
Sonorus StudI/OYY'Customer results' — not tested by Magma

Magma also say that their chasses will work with the following Digidesign systems, although only the six‑, seven‑ and 13‑slot models are currently Digi approved:

  • Digi 001 with Pro Tools 5.01 software.
  • Audiomedia III, SampleCell, Pro Tools Project, Pro Tools III (except on Wall Street 233 and 250 models), and Pro Tools 24. In each case, Pro Tools 5.01 software and an AMCC chip designated 'QC' or higher are required.
  • Pro Tools 24 Expanded, Mix and Mix Plus systems will work on Wall Street Powerbooks, and the relevant expansion chasses, only. Magma also warn "For some reason, Mix will not work if there is a SCSI card in the chassis with the Mix cards."


  • Hosts full‑length PCI cards.
  • Works with all current Powerbook models and the majority of audio cards.
  • Better footprint for Powerbook than previous units.
  • CB2S accommodates a large‑capacity SCSI 2 drive.


  • Does not work with Wall Street or Lombard Powerbooks.
  • Not ideal for Digidesign systems as it is not approved and has only two slots (though larger models are both Mix Plus‑compatible and approved).


Until mLAN makes audio expansion via FireWire a reality, this is the only game in town for the portable multi‑channel audio workstation.