Speck Electronics MicPre 5.0 - Manual (Page 33)

When you are evaluating voltage and current requirements for your
audio system, it is important that your MP 5.0 and/or audio system
does not exceed the capacity of your AC service. You should make
certain that the earth (green) wire for the AC system makes a
reliable earth connection, and determine as best as possible that the
AC system is free of noise that could generate unwanted audible
sounds or cause problems in microprocessor based equipment.
When using a larger rack system it is recommended that a
dedicated and isolated AC service be provided. This service
should have its own AC wires, isolated receptacle, and breaker and
not be shared with other unrelated equipment.
Even with an isolated AC system, it may still be necessary to make
use of surge protectors, line filters, isolation transformers, or all of
the above. Power conditioners should be selected with care, since
they sometimes generate undesirable switching noises in audio
systems.
When connecting many pieces of electronic equipment to an AC
system it is important that the AC is properly distributed. It is
better to connect all plugs to a common AC source than to have AC
receptacles in different locations.
When installing a large audio system, it may be necessary to
consult a qualified electrician that is familiar with the specialized
style of electrical wiring required for recording studios.
Clock noise is one of the greatest enemies of the audio racks AC
system. If a computer or any microprocessor based device (most
samplers and effects are) emits or somehow couples its clock
signal with the neutral or earth of its own power cable, it will
contaminate your AC system and carry the clock noise into other
equipment; almost always with undesirable results.
The AC earth connection exists to protect you, your equipment and
possibly your building from an electrical disaster. In a properly
wired system, if a 120 volt AC wire were to break within your
equipment's chassis, it should make contact with the Safety Earth
Wire that is connected to the chassis, and blow the fuse or trip the
circuit breaker until the problem has been corrected.
AC Distribution
and Safety
Proper AC grounding
Quality AC system
AC distribution
Clock noise and AC
Safety earth connection
Chapter 4 Wiring and Other 27