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Friday, March 14, 2014

Rackmounting Your PC

PC Musician

Technique : PC Musician
Putting your PC in a rack has a number of advantages. Apart from getting the machine out from under your feet, and making it easier to take on the road in a flightcase, there are security benefits too. Here's how to perform the conversion, and potentially make your PC quieter at the same time.
Daniel James

If your studio is the kind that has people walking in and out with gear every day, or you are unlucky enough to live in an area where burglary is common, a sturdy rack case combined with a fixed cabinet and a set of security-headed bolts could help preserve your investment. Losing hardware and software is bad enough, but no amount of insurance cover can replace studio projects stored on a stolen hard drive. In an ideal world we'd take an off-site backup of all our data every day, but in practice most of us don't. Just imagine how long it would take to get up and running again if you lost everything on your PC tomorrow; possibly weeks, or even months.

Unless you bought your PC from a specialist studio supplier, it's likely to be built into a tower or desktop case. As the mass market in PCs has brought prices down, corners have been cut on the materials bill. The cheaper cases can be quite flimsy, often being made of plastic panels push-fitted to a thin steel chassis. It seems the studio market just isn't big enough to interest the large PC manufacturers, and even the new Intel-based Mac Pro comes in a tower case. While you can make your own rack brackets, or put a tower on its side in a rack tray, this is far from ideal. For one thing, CDs will probably fall out when you eject them, if the optical drives are now mounted vertically. For another, you probably won't want to drill your case to make it secure. If the case is really flimsy, there might not even be anything strong enough to attach a bracket to.
Server case fans are designed for high air volume, not quiet operation — so we can replace them with lower-speed versions, or use a fan-speed controller.

Stock CPU coolers can be replaced with more efficient models for quieter performance. Here, on a Tyan S2875 dual-Opteron motherboard, two Akasa heatsinks have their fans mounted in a push-pull configuration.

Fortunately, there is a wide range of purpose-built 19-inch (482.6mm) rack cases on the market, due to the fact that audio racks have the same width and mounting-hole spacing as racks designed for servers. Since the dot-com boom there's been a massive demand for low-cost web-server hardware, which means that these rackmount cases are now only marginally more expensive than regular PC cases of equivalent quality. There's even an international standard to make sure your gear will fit — it's IEC (International Electrotechnical Commission) standard number 60297, which you can look up on the web if you're handy with metalwork and fancy building your own case. However, unless you have very particular requirements it will almost certainly work out cheaper to buy a rackmount case 'off the shelf', with prices starting at well under £100 for cases without power supply units. If you're performing a conversion from a desktop case, you'll probably already have a PSU that will fit, although you might want to take the opportunity to upgrade to a quieter or better-quality one.

When converting your PC from tower to rackmount, or building a rackmount machine from scratch, there are a few factors to bear in mind. Firstly, cases intended for servers are likely to be deeper than many audio cabinets and flightcases allow clearance for, due to the large EATX dual-processor motherboards that server cases are often designed around. Secondly, server cases are not usually optimised for quiet operation, since server 'data-centres' assume high CPU density and extreme amounts of cooling, usually in air-conditioned buildings.

How Many U?

The fact that data-centre space is priced in 1U increments has meant that a lot of server cases are thin, typically only 1U or 2U in height. These cases are not particularly useful for studios, except in some specialist applications, such as headless nodes for disk-streaming samplers. The chief problem with these cases is that they cannot accommodate PCI audio and graphics cards, except perhaps on a horizontal riser which obscures the other expansion slots. In many cases their internal height clearance is insufficient to allow the fitting of a quiet CPU cooler, which most studio owners would wish to fit in place of a noisy stock unit. Worst of all, the low front and rear panel height will only allow small case fans to be fitted, and as SOS readers who've ever tried to build a studio PC will know, small fans turning quickly make a great deal more noise than large fans turning slowly.
The Antec Take 3 is one of the first rackmount PC cases to have been designed specifically for studio use.

The Take 3's side fan, where the PSU would normally be, means that the case will work best if the rack cabinet is not fully enclosed.

The Take 3's front door looks secure, at first glance...

...but inside we can see that the hinge and door surround are made of plastic.

The smallest case size that will take PCI cards vertically is 3U, while 4U allows for larger case fans, so these are both reasonable sizes to choose. Server cases of 5U and 6U are also available, but these probably take up more of your rack space than is required for a typical PC setup. These larger cases are often specified for RAID arrays, where the front-panel space is required for access to up to a couple of dozen hot-swap drive bays.

Quiet Rackmounts

The rackmount noise problem has begun to be addressed by some of the specialist case manufacturers, who have launched models designed explicitly for the studio market. These cases feature both a standard 19-inch IEC fitting for the front flanges and some innovations in noise reduction. Antec, case manufacturers who will be familiar to builders of quiet PCs, have launched 521mm-deep 3U and 4U ATX cases in their 'Studio Series', known as the Take 3 and Take 4 respectively. The Take 3 has an unusual design, in that the power supply is at the front instead of the rear of the case, with an exhaust duct removing warm air to the side. This prevents the waste heat from the PSU mingling with that generated by the CPU fan, and leaves room at the rear of the case for a couple of fairly large case fans, one of which is on the side. This side fan should improve cooling without adding much noise, as long as the side of the rack cabinet isn't completely enclosed.

The Take 3 may well be the quietest rackmount case currently on the market, but from a security point of view it isn't the toughest. Although the Take 3 has a lockable front door, which is a good idea to prevent tampering with your PC, the hinge on the door is made of plastic, and the top of the door is too. As any locksmith will tell you, a lock is only as good as the door and frame it is fitted to, and this door looks as though leverage from a large, flat-bladed screwdriver would open it fairly easily. Still, the rest of the construction is of good quality, and it weighs less than 12kg without parts fitted, which is not bad for a case made mostly of steel. Priced at £159 plus VAT and delivery from X-Case (www.xcase.co.uk), it looks on the expensive side, but considering that it includes a 450W quiet power supply and two quiet fans with speed controllers, it's actually pretty good value. It also comes with a very good installation manual and a three-year warranty on parts and labour — unusual for PC cases. The larger Take 4 case is more conventional, with the PSU at the rear, although this features its own air inlet. It retails for £169 plus VAT and delivery, but again includes a 450W quiet power supply. The extra 1U in height over the Take 3 allows for more drive bays, a total of eight, instead of six; more than enough for most studio applications.

Server Cases

The alternative is to take an off-the-shelf server case, then fit a quiet PSU and some quieter fans. It has to be said that this approach probably won't result in a quieter case, and could work out at about the same cost. You would probably have to fit some variable resistors to adjust fan speeds, plus other noise-tweaking parts, such as vibration-reducing grommets on drives.
The Compucase S411 is a tough server case, but it's heavy — and deep, too.

Antec's Take 4 allows more room for drives than its Take 3 sibling.

What the better server cases have going for them is heavy-duty toughness, free of weak plastic components. The Compucase S411 is a 4U case with an all-steel construction, so the lockable front door feels significantly stronger than the door on the Antec Take 3. I chose one of these cases for my own studio; ultimately, I judged its security features to be more important than noise damping. The S411, pictured at the start of this article and above, is reasonably priced at £89 plus VAT and delivery from X-Case, not including a power supply, but it is longer than the Antec cases, at 560mm deep, and the amount of steel in the case means that it weighs 17kg before you've put any parts in it. It's not a case you'd want to move often once it's fully built-up, but it will take the larger dual-processor EATX motherboards, and has room for up to 10 drives. 

There's also a 420mm-deep version available at the same price, called the Compucase S400, but the optical drive-mounting hole in the front panel is vertically orientated, which somewhat defeats the purpose of a specially-designed rackmount case. [Compucase now also have an S400 with horizontal drive bay on the market — Ed.] Of course, most servers aren't burning audio CDs all day, and only feature optical drives for initial software installation.

Another advantage to using server cases is that there's a broader range of shapes and sizes available. For instance, the demand for high density in data centres means that there are several short-depth rack cases on the market that can be fitted back to back, with the computer's I/O panel on the accessible side of the rack, which is potentially very handy in a permanent installation. The Janus range of cases from DV Industrial Computer (www.inpc.com.ua) can be assembled to face in either direction, with the 3U DS35 model being only 275mm deep, and therefore short enough to fit in a rack of typical outboard gear. The disadvantage of this case is that it will only take a micro ATX motherboard, limiting choice for system builders, and there isn't room for more than one optical drive and two hard drives. The build quality isn't as good as the Antec or Compucase products, but that's reflected in the price of £70 plus VAT and delivery from Avrio Ideas (www.avrio.co.uk). The case takes a standard power supply, which is available from Avrio Ideas for an additional £25 plus VAT, but the model supplied is the cheap generic PC kind, and a false economy for a studio machine. It's a much better idea to fit a quiet PSU from Antec or Zalman, or even to re-use an existing PSU you have, if it's a reasonably good one. Still, with its very compact size and weighing only 5kg without the PSU, the Janus DS35 is potentially a useful case for a road rack, or when space is otherwise restricted. A system this size would make a tougher and more serviceable alternative to a laptop for a DJ, a band playing soft synths live, or a mobile recording setup.

A Question Of Power
The Janus DS35 is a very compact and lightweight case, but it's restricted to micro ATX motherboards only, and there's little room for expansion.

Shown here during the build-up, the DS35 case is still a good option for a mobile rack.

PC Musician9.s
If you're changing the power supply during the transplant, it's vital to make sure the new one is compatible with your motherboard.

Once you've discovered what format of case you need (see the 'Identify Your Motherboard' box) and decided on a design, it's time to perform the transplant. But first, take a fresh backup of your precious music projects. Hard drives are vulnerable to shock and static, although they're pretty difficult to damage by incorrect connection. More likely, if the PC doesn't work properly when you switch it back on, you could accidentally reformat the wrong partition while attempting to reinstall software.

You'll need a decent-sized table to work on; a dining table should do, if you put a tablecloth on it to avoid scratches, and corresponding censure from family members who take a personal interest in the condition of household furniture! Next — and this shouldn't need saying to SOS readers — disconnect your PC from the mains before opening the case. Computer power supplies are designed to deliver low voltages, but the currents can be high: you have been warned.

With the old case open, if you don't already have the motherboard manual to hand, read off the motherboard make and model number from its PCB. Using these details, you should be able to download a PDF of the manual from the manufacturer's web site, which will be very useful during the re-assembly. If you're changing power supply during the operation, you can read in the manual what kind of power supply your motherboard requires (they're not all the same). If your system is fairly recent, it's likely to use one of the following power supply standards:
ATX12V: One 20-pin connector, one 4-pin, one 8-pin.
ATX12V 2.0: One 24-pin connector, one 4-pin.
ATX12V 2.2: One 20-/24-pin detachable connector, one 4-pin.

If it's a Xeon or Opteron machine, it might have an EPS12V power supply with a 24-pin main connector, an 8-pin secondary connector, and perhaps the optional 4-pin connector. If you use the wrong type of PSU, you might get the system to boot up, but the voltages could be incorrect or the amount of current delivered insufficient, causing system instability. Your motherboard manual will provide figures for the current requirements of the system, and a sticker on the PSU should list the amperage that it can deliver.


With the new case open next to the old one, and having established that the new power supply (if required) is of the correct type, you can take notes on which slots any PCI or PCI Express cards are fitted into, and which way around the hard drives and optical drives are connected. If you put the system back together differently, your drives may boot in the wrong order, or carefully tweaked interrupt assignments may change. At this point you should remember that static electricity can damage PC components, and either ground yourself to the old and new cases with a brief touch of the finger or, for the well-prepared, fasten the anti-static wrist strap that you had already purchased. If you work on PCs often, you might consider buying an anti-static mat for your table. Of course, you should always handle motherboards and PCI cards by their edges, and never touch any exposed metallic connectors.
PC Musician10.s
When you open up the PC, it's a very good idea to take notes on how the cables are attached.

Having disconnected the drives, the power supply, any case-mounted headers and the small, fiddly wires that connect to case switches and LEDs, you can now remove the PCI, PCI Express or AGP cards. Place these in anti-static bags during the transplant (if you don't have any, your local computer shop can probably find you some). There's usually no need to take the RAM out, and I'd recommend leaving the CPU in place too. The CPU cooler and fan can come off if you plan to upgrade it during the operation, or if it's particularly large and unwieldy; otherwise, leave it in place. Certainly, don't remove the heat sink unless you've got some fresh heat-sink compound, and preferably a purpose-made degreaser to get the remainder of the old gunk off. This sticky compound fills the microscopic air holes between the CPU surface and the heat sink, and without it your heat sink won't work efficiently.

Next, remove the screws that hold the motherboard in place, without dropping any of the screws back on the motherboard. They could cause short circuits if they get wedged down there and you forget about them until you switch the machine back on later. A very small dab of Blu-Tack on the end of a Philips screwdriver can help get them all out safely. Then take a look at the new case. Are there small threaded tubes welded on the floor of the case, corresponding to the mounting holes in the motherboard? These aren't for screwing the board to directly; they are for the hexagonal brass motherboard spacers which will have been supplied in a small plastic bag with the case. If you leave these spacers out, none of your PCI cards will line up properly. You may also end up with the heat-sink backplate wedged against the case floor — not good. So screw these spacers in first, until they are good and tight; otherwise they'll unscrew themselves if you have to take the motherboard out later.

Identify Your Motherboard
It's important to get the right case for your motherboard, as some of the designs are incompatible and adapting the wrong-sized case would be difficult. There have been quite a few different PC motherboard sizes available in the last 20 or 30 years, but luckily we usually only need to consider a few of them when contemplating a transplant into a rackmount case.
Common sizes:
ATX (305mm x 244mm): Designed by Intel and used in the vast majority of PCs over the last decade, so most cases are made to accommodate this size of motherboard.
EATX (305mm x 330mm): Extended ATX size, usually only found on motherboards with two or more processor sockets. Even if your PC is dual-core, it probably only has one CPU socket, as dual-socket boards are significantly more expensive. It has the same I/O panel as ATX, so is compatible if the case is deep enough.
Micro ATX (244mm x 244mm): Fewer PCI slots than an ATX motherboard, but again the I/O panel is the same, so usually compatible with standard ATX cases. Quite common in small PCs, often featuring motherboards with integrated graphics chip sets, which are adequate for use in audio systems.
Less common sizes:
Mini-ITX (170mm x 170mm)
Nano-ITX (120mm x 120mm)
Pico-ITX (100mm x 72mm)
These are three small-form-factor standards from Via. Not at all compatible with ATX cases, but there are some rack cases available in these sizes from Mini-ITX.com. You would be unlikely to have one of these boards in your PC unless you had built it yourself, as they are most popular in the DIY and industrial PC markets.
BTX (325mm x 267mm)
MicroBTX (264mm x 267mm)
PicoBTX (203mm x 267mm)
The above are standards from Intel that were designed to replace ATX and launched a couple of years ago. These formats have not caught on yet, except with the large-scale PC manufacturers. There are very few after-market cases available to buy in these sizes, although some industrial computer manufacturers do produce a BTX rackmount.
DTX (200mm x 244mm)
Mini-DTX (200mm x 170mm)
These two new standards were launched by AMD earlier this year. You would be very unlikely to have one of these boards yet, and at the time of writing, cases aren't generally available.

Reassembly & Fitting
The Compucase S411 mounted under a studio desk with security bolts and steel rack-strip. That PC is not going to come out without a fight!

Now you can fit the motherboard to the new case and reconnect the PCI cards, power supply, case connectors and drives. If there are variable resistors on the new case-fan power leads, you can set these to halfway initially. Once you've fitted the new case cover and booted the newly-assembled machine for the first time, you could check fan speeds in the BIOS, and also that any temperature-sensing fan-speed control features are enabled. For peace of mind, you can install desktop software for most operating systems that will keep an eye on CPU and system temperatures, or monitor fan speeds, which can alert you to any problems. PC cooling is very sensitive to ambient room temperature, so fan settings that are appropriate for a cold spring day may not provide enough cooling in midsummer — or, for that matter, in a hot and humid venue during the moshing hour. School physics lessons told us that a black metal surface in direct sunlight can get hot enough to fry an egg, and indeed it's still true; keeping the rack in the shade seems to make a big difference to the amount of cooling noise produced.

Further Protection

If you're taking the PC on the road, you can choose from traditional plywood or moulded plastic flight cases. The plastic cases are lighter, but the plywood ones are easier to get in custom sizes, which is worth considering if your rackmount PC case is on the deep side. SKB make a couple of shock-absorbing flight cases, available from Studiospares (www.studiospares.com), which contain a floating rack suspended inside the shell, but they aren't cheap, at £325 for the 8U case and £369 for the 12U version (plus VAT and delivery). However, the investment might be worthwhile if you know the case is going to have a hard time at the hands of the roadies or the airport baggage handlers.

When it comes to the choice of rack or cabinet for indoor use, the DIY route is quite practical. Cabinets can easily be assembled from 18mm MDF, with lengths of steel rack-strip and cage nuts bought from Studiospares at modest cost. The rack strip can be cut with a hacksaw to fit any cabinet of the right width, and for a secure application Studiospares also sell the security bolts used in telephone booths, which can only be unscrewed with a special Allen key. Build the rack furniture into the studio room, or at least make it too big to take out through the door, and you've made a thief's task considerably more difficult. The only disadvantage is that if you need to do any work on the PC you have to remember where you left that special Allen key!

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