are required to implement this approach, since ground
is not carried between components. One drawback is
that cables may not all be the same – some having
shields carried through at both ends, and others not,
depending on the equipment – so it becomes more
complicated to sort out the cabling upon setup and
breakdown of a portable system.
Figure 4-10 illustrates a typical audio system in
which various grounding techniques are combined. The
basic rules that guide the choice of grounding schemes
may be sum-marized as:
1) Identity separate subsystems (or equipment envi-
ronments) that may be contained within an electro-
static shield which drains to earth.
Equipment Rack
2) Connect signal ground within each separate sub-
system to earth at one point only.
3) Provide maximum isolation in connections between
subsystems by using transformer coupled floating
balanced connections.
4.3.4 Balanced Lines and Ground Lift
Switches
By using balanced signal lines between two pieces of
sound equipment, you can lift (disconnect) the shield at
one end (usually at the output) of an audio cable and
thus eliminate the most likely path that carries ground
loop currents. In a balanced line, the shield does not
carry audio signals, but only serves to protect against
static and RFI, so you can disconnect the shield at one
Mix Console
Figure 4-10. Combining Grounding Techniques in a Practical System
Page 4-8
Summary of Contents for PM4000
Page 1: ...PROFESSIONAL AUDIO MIXING CONSOLE PM4000 OPERATING MANUAL YAMAHA ...
Page 2: ...PM4000 OPERATING MANUAL ...
Page 7: ...Section 1 Introduction ...
Page 11: ...Section 2 Brief Operating Instruction ...
Page 47: ...Section 3 Specifications ...
Page 51: ...Dimensional Drawings PM4000 Console all versions Page 3 4 ...
Page 52: ...Page 3 5 ...
Page 53: ...Page 3 6 PM4000 Console Rear Profiles ...
Page 54: ...Module Block Diagrams See back of the manual for overall system block diagram Page 3 7 ...
Page 55: ...Page 3 8 ...
Page 56: ...Page 3 9 ...
Page 57: ...Page 3 10 ...
Page 58: ...Page 3 11 ...
Page 59: ...Page 3 12 ...
Page 60: ...Section 4 Installation Notes ...
Page 72: ...Figure 4 13 Cables For Use With Balanced Sources Page 4 12 ...
Page 79: ...SECTION 5 Gain Structure and Levels ...
Page 82: ...Figure 5 1 Dynamic Range and Headroom in Sound Systems Page 5 3 ...
Page 86: ...Section 6 Optional Functions ...
Page 106: ...Section 7 Operating Notes and Hints ...
Page 119: ...Section 8 Applications ...
Page 127: ...Section 9 Maintenance ...
Page 131: ......
Page 132: ...YAMAHA VN02300 ...