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Bryant Unlimited SDU 112P

12-way Mains Distribution Unit By Hugh Robjohns
Published April 2014

Bryant Unlimited SDU 112P rack mount mains distribution unit.

Managing mains power distribution in a project studio can be frustrating. Simple plug-boards are cheap and easy, but usually end up being placed at the back of equipment racks where they are hard to get at. Professional rackmounted mains distribution units (MDUs) allow neat centralised cabling, but are usually permanently powered. Most of us, with half an eye on soaring electricity bills, want to be able to switch things off when not in use, and often to switch subsets of equipment on or off depending on what we're doing at the time — and ideally without having to climb around the back of equipment racks to access the power switches!

Turning everything on from only one or two wall sockets is a common solution, but the power-on surge current may exceed the power ring breaker rating in some cases, and the instantaneous leakage current to ground through multiple equipment's mains filters may generate a sufficient momentary ground current surge to trip the consumer box RCDs! For all these reasons, I have been looking for a professional MDU with individually switched outputs, allowing me to choose the equipment I want powered on or off (and in what order). Unfortunately, while there are plenty of globally switched MDUs, and lots of expensive, sophisticated ones that can be remote-controlled vianetwork IP or automatically sequenced, none of these suited my needs or budget. Not for the first time, I then discovered that Bryant Unlimited manufacture exactly the thing I've been looking for!

The SDU 112P is a 1U rackmounting unit in a brushed-aluminium case. The rear panel carries 12 separate IEC mains outlets, each rated at up to 5 Amps, with a single Neutrik 20A Powercon input socket (a suitable plug is included). A strong lacing bar extends from the rear panel to allow mains cables to be secured and loomed neatly in the rack, and an external earthing terminal is also provided. Internally, the SDU (switched distribution unit) is wired neatly and safely, and inherently with 'star earthing' to minimise the chances of ground loops! There is no 'spike protection' or mains-filtering malarkey here, just well-engineered and immensely practical mains power distribution.

The front panel carries a large red 'mains present' indicator, and each of the 12 output channels is equipped with its own fuse holder and illuminated (single-pole) on-off rocker switch. A set of pre-cut paper labelling strips is included for insertion behind a protective cover above the switches to identify the power circuits. The unit doesn't have an input fuse, but anti-surge T3.15A fuses are fitted in each output circuit, and if one should blow, the corresponding switch's neon light goes out, so power supply failures are very obvious and easy to track down.

Installing the SDU 112P is straightforward, and the lacing bar makes it very easy to organise the mains cabling neatly, and to keep it well away from audio cables in the same rack. You will require IEC-IEC cables (or IEC-13A mains sockets) to power the individual equipment, but these are cheap enough and so that's really not a problem. Individual channels can be toggled on or off very conveniently, and in anydesired order — so active speakers or power amps can be powered up last and off first, computer interfaces can be powered up before booting the computer, and so on — and all from one central location, without you having to scrabble around under desks or squeeze yourself in behind your racks! Provided the total equipment load is below the individual channel and overall current limits, multiple related devices can be powered from a single SDU channel using appropriate plug-boards or Y-split mains cables, too. Most modern audio equipment consumes little power, and the SDU 112P will tolerate up to 700W on an individual channel if necessary.

The SDU 112P may seem like an expensive solution to a rather basic problem — and, indeed, it is — but given its apparently unique design, its eminent practicality, and the excellent build quality I feel the cost is justified. It's certainly made life in my own studio considerably easier! Hugh Robjohns

£190.46 including VAT.

About $250 at current exchange rates.