Frequently Asked Questions

Grounding - Class 1 and Class 2

There are certain safety requirements for electrical appliances (including audio) that force either an earthed device (Class 1 equipment) or one with double/reinforced isolation (Class 2 equipment).

More here:
https://en.wikipedia.org/wiki/Appliance_classes

For smaller manufacturers the requirements of testing and approval for Class 2 equipment may be forbidding, so "boutique audio" often uses Class 1.

Either Class is legal and if designed and tested correctly safe. So it is not question of "should it have an earth?" no matter if devices have earth or not, problems with noise may arise.

If a system contain multiple Class 1 devices - the potential for earth/ground loops is created that can lead to measurable or audible hum and buzz.

If a system contains only Class II equipment - the potential for "missing earth" noise (hum, buzz, RFI etc) is created as now all the audio systems shielding is no longer connected to the local earth but floating, so the shielding becomes an antennae that picks up noise.

But if a system contains only one Class 1 device and any number of Class 2 all is well and happy.

Due to historical reasons many people will identify the second case as a earth/ground loop, when in fact it is the opposite!


How to treat the problem depends on its nature.

In the first example, one may briefly try cheater-plugs on the computer (with necessary precautions against electrical shock). If that kills the noise, using an original iUSB Power, iUSB3.0 micro with iSOGround, or iDefender 3.0 will break the earth/ground-loop and remove or dramatically reduce the noise.

If removing the computer's earth (cheater-plug or cable) does not remove the noise then neither will any current iFi device!

If a missing earth is suspected simply introducing a single Class 1 device into the system, even if switched off and never used, will add the missing earth. If this earth solves the noise - missing earth, simply keep the piece there, get something from a charity shop or invest into a earth/ground management system such as the Groundhog (or if capable of a spot of DIY improvise a supplementary earth connection).

If neither removing the earth from the computer, nor adding an earth (Class 1 device) into the system solves the noise, it has other sources and needs to be resolved accordingly.

Disclaimer: This article outlines how we would diagnose. Not how you should diagnose. One should always ask a qualified electrician to troubleshoot as mains voltages can kill.

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