completely out of the IEC connector and not only holds the fuse, but has a spare fuse
in it as well.
GROUND LOOPS, POWER STRIPS, HUM
Whenever we connect more than one audio component together we run the risk of
creating a ground-loop which causes hum.
A ground loop happens when the path to ground in one component finds an easier
(less resistive) path through another component via the ground or shield wire in your
interconnects. This is a common problem when components are plugged into different
outlets or a power strip is used, as the resistance varies at the ground point of each
receptacle.
Ways to combat the problem are - try to plug everything into the same outlet when
possible, do not use power strips, try to keep the length of the power cords the same.
If all else fails, you can try lifting the ground on one or more component until the hum
goes away.
How to tell if you have a ground loop causing hum - simply remove all your
interconnects from the input jacks of your amplifier so that the only thing hooked to it is
your loudspeakers. You should hear no hum on all but the most efficient speakers and
even those would sound quiet from the listening chair some 6 or 8 feet back. If you do
hear hum, then it’s likely the amplifier assuming your speaker wires are not wrapped
around a power cord somewhere. The most likely cause if it is the amplifier itself would
of course be tubes. Start by installing a new rectifier tube and see if that corrects it. If
not you can systematically try the remaining tubes in the amplifier.
If the amp is acceptably quiet just hooked to your loudspeakers with no inputs
connected, then hook your inputs up one component at a time and listen for hum. If
you get hum, then you either have a ground loop between that component and the
amplifier, or that component is bad.
O W N E R S M A N U A L
Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
