Appendix E Best Grounding Practice; Safety First; Ground Loops - Midas Venice F32 Operator's Manual

Appendix E: Best Grounding Practice
This appendix gives details of the best grounding practices for the VeniceF console in
order to get the optimum performance out of it.

Safety first

The VeniceF is classified as a class 1 device and as such there is a safety
requirement for the power cable to provide an earth connection to the console.
This connection is bonded to all external metal parts such that in the event of
a failure within the AC power systems it is impossible for any external parts of
the product to become live. When connecting other equipment to the VeniceF
to form an audio system, it is likely that some of these additional devices will
also be class 1, so they will require a safety earth too. For your own safety,
the safety of others, and to comply with the law, it is important that none of
these earth connections are tampered with in any way.

Ground loops

When connecting audio signals or data between devices within an audio system, a
signal ground connection must be provided that screens the signals from
electromagnetic interference. This ground connection, combined with the safety earth,
produces a ring of conductors often referred to as a "ground loop". Typically, this gives
rise to induced currents within the components of the loop, namely the ground
conductors, the chassis of the equipment and the safety earth conductors. This is not
dangerous, but if the grounds are used as a reference for audio signals, as occurs with
unbalanced connections, the ground currents may generate small voltages that corrupt
the signal integrity. The audible results are noise added to the intended signal.
Typically, this sounds like hum (from the power AC voltage), buzzing or whistles (from
power supply diodes or switch mode power supplies), or digital noise (from computers).
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Operator Manual
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