User's Manual

Juice will flow down the shields and broadcast hum into the signal wires they were
supposed to protect or wind up imposed on the reference ground of the receiving equipment.
This situation manifests itself as the all too familiar buzz of a ‘ground loop’. The intensity
depends on many variables but can go from unnoticeable to raging. Some people in
desperation resort to using AC plug “ground lifts” to defeat the mains safety grounds in a
random fashion until the system quiets down a bit. This in our view (and the view of the
international safety standards organizations) is an unacceptable method of taming ground
buzzes. The simpler way is to make sure that all the gear has a good mains ground and to lift
the shields on the receiving ends of the audio cables. The principals at Dangerous Music
have wired up large, world class facilities using this scheme and have brought room after
room online with no buzz problems from the moment of power up. This is why many gear
manufacturers have shield lift jumpers inside their equipment. If a noise problem crops up,
changing the jumper position will almost always cure the problem. Planning out the wiring
system to minimize the formation of ground loops solves problems before they happen.
In contrast to other devices in a recording system, many powered speakers seem to get
their audio reference ground from the input cable. This means that these shields should not
be lifted at the XLR.
Our favored technique for trouble shooting buzz issues is to make a short XLR cable
with the shield lifted on the male connector and use this to test whether or not an XLR
interface warrants a shield lift.
The ST Remote however, must always use a shielded cable/connector (please use the
one supplied by Dangerous). Failing to do so will void your warranty. Using an unshielded
cable will leave the remote susceptible to static discharge, which can cause damage.
Do I turn my gear off at night?
This is a good question and one that takes some reflection to answer. There are several
issues to be weighed in making the decision of what to do with unattended gear. Equipment
that is powered down when the facility is not in use can’t be damaged by power problems
short of a direct lightning strike, however, turn-on transients can, over time, lower the
reliability of equipment because of inrush current spikes. On the other hand, a room left
powered and unattended can result in blown speakers if the power company has problems
and there is no one to turn the room off. If one lives in a stable power situation (non-rural or
power-conditioned), our preference is to leave the monitor section, A/D converters, and
solid state power amps on unless the facility will not be used for a time.
Over the years, the experience of the Dangerous team has been that gear left on is
more stable in performance and sound quality, and doesn’t really cost very much in extra
power consumed. Solid state amps and converters can take several hours to stabilize in
temperature and the sound quality is a moving target while things are warming up. Having
said that, the writer has come home to his studio and found smoked speaker cones (bummer)
due to Con Edison power switching problems. This issue is a tough call and really situation
dependant. Studios that power down daily can lose a piece of gear now and then to the
rough reality of daily power-up. The repair bill is likely more than the extra electricity
consumed had the equipment stayed on.
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