where do I connect the earth in my pre to?

In some countries the term "earth" is used to mean the same thing that the term "ground" refers to in the USA, which in this case would mean chassis ground/circuit ground/ac safety ground (all of which are usually connected together in audio components that have three-prong power plugs).

So what is labelled "earth" on your preamp is just the ground thumbscrew the others have referred to, that is usually provided on preamps. It should not be connected to the physical Earth.

Some countries, including among others Russia and some parts of Argentina, according to this Worldwide Voltage Guide, appear to have only two-prong ac outlets. That would reduce or perhaps eliminate the potential for ground-loop problems, which is probably what was behind the comment that "the earth connection is for US electrical systems only."

Regards,
-- Al

OK, thanks for the feedback.

Al: that website is outdated. 3-prong installations are mandatory here. Also, it's not me using the term "earth"; it is printed on the back of the Lamm, which is a unit initially meant to be sold in the US.

I guess I'll forget about it: I don't experience any ground loops, no hum or hiss, except a little hiss I can hear with my ear to the tweeter and the volume wide open.
And I have no vinyl.

Thanks all for the input!

It's not me using the term "earth"; it is printed on the back of the Lamm, which is a unit initially meant to be sold in the US.

Yes, I understand. Note that I referred to "what is labelled 'earth' on your preamp." I had looked at a photo of the rear panel of the LL2 prior to submitting my post.

What I was implying is that since the term "earth" is used in some non-USA countries to mean the same thing that the term "ground" is used to mean in the USA, and since the preamp was designed by someone whose native country was not the USA, the "earth" designation was most likely intended to mean "ground," not the physical "Earth."

Regards,
-- Al

A further note FWIW: unless your home's electrical system is sorely in need of update, there is no need to pound a stake in the yard for an electrical ground. The ground prong of the AC cord should go to the house's central AC ground, which in turn is usually connected to a cold water pipe.

You can have a different potential with a ground stake, which may well vary with water content in the soil. All that is is a recipe for trouble- the house ground is the only thing that matters.

Now audio gear in general does not like to be grounded but in order to sell it legally, it has to be grounded. You will find that various manufacturers are at various stages of development in this regard- some will have grounding schemes in their equipment that work flawlessly. Others will have outright errors that can introduce ground loops and still others will not be grounded at all.

So there is a big IF that is going on here. IF the equipment is built correctly, there will be no benefit whatsoever from any additional grounding beyond that of the AC wall ground. IF the equipment has bugs in it, then *maybe* a stake in the yard might help, but IMO and IME the stake in the yard solution is not only inconvenient, its asking for trouble. Its best to sort out what the bug in the gear is, even if that means getting the manufacturer to find a proper solution.