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DA-5H Grounding Techniques
The DA-5H contains a switching power supply that will add an audible
hum to your audio signal if the unit is not plugged into a properly
grounded three-pin AC socket. Unless you’re using a “star ground
network” (see below), you must not use an adapter to lift the ground
from the DA-5H AC cable.
If the DA-5H is correctly connected to a grounded three pin socket and
you still experience hum or buzz when using it with other audio devices,
there's a simple test to determine the source of the problem: with all
devices powered on and connected with audio cabling, physically
remove each device, one by one, from the rack. If the hum disappears
when a particular device is removed, you'll know that that device is the
culprit. If the offending device uses a two-prong plug (or an external
two-prong AC/DC adapter), you can try reversing the plug in the socket.
If that doesn’t work, you may need to physically ground that device’s
chassis by connecting a wire (called a strap) from it to a grounded piece
of metal such as rack ears. Some pieces of equipment have a screw-
type ground post to which the strap can be connected; if not, you can
attach some kind of metallic binding post to the case itself.
In addition, you can minimize possible interference by planning your RF
antenna, audio, electrical, and computer cable runs so that they are as
far apart from one another as possible and so they don’t run parallel to
one another. If they have to cross, try to ensure that they do so at a 90°
angle (that is, perpendicular to one another). In particular, try to keep
audio cabling away from external AC/DC adapters
If you’re using the DA-5H in a fixed installation, you may want to invest
the time and money into creating a star ground network for all your
audio devices. This is by far the best technique for avoiding grounding
problems. It involves using a formidable ground source such as a cold
water pipe or a copper spike driven into the earth. A thick grounding
cable is connected to that source and is then brought to a central distrib-
ution point; from there, individual cables are connected to each piece of
equipment. This setup also requires that you lift the ground plug of all
three-prong AC connectors, so there is the possibility of danger if it is
done incorrectly. We strongly recommend that you contract with a
qualified professional to carry out this or any kind of electrical work.
