Some units have earth connection, others don't

[Asterduc]

Got a question that kept me busy some time.

This topic goes about Earth looping problems on european units delivered with a Shuko power cable connector.

The power plug / connector on my RSX-1056 is missing the "middle Pin" which in fact is the Earth connector. My Marantz DR-700 connects also without the Earth wire as it has only a 2-wire power cable. My Denon DVD 2910 on the other hand does have the Earth connection in the Shuko plug.
This caused a Earth-looping Hum-problem as the Earth came in on the Denon and was forwarded to my Rotel over the Analog CD cable. In addition it went also over the HDMI connection to the projector and back over the Component cable into the Rotel.

I fixed the Hum-problem easily by adding en single Earth cable from the Rotel chassis to the Earth connection of the power plug.

Why does Rotel and others don't use the Earth wire in the Power Cord?
Wouldn't this solve many of the Hum problems you can read about in this forum!

Ed.

[basementjack]

earthing is a little more complicated than that.

in order for it to "help" the rotel - the audio plane would need to be "earthed" - while this would be at the same plane as all other "earthed" components, it opens the possibility that a "dirty" "Earth" wire would contaminate the music.

There is really nothing wrong with "floating" the entire audio chain - Speakers are Rarely "earthed"

This does unfortunately bring up occasional problems when components are mixed and one has attached the AC "earth" line to the Signal paths "neutral" line.

In these cases, you might be best to experiment with an adapter to disconnect the "earth" wire of your power feed - over here in the US - our current power standard is 3 wires, with one being "Ground" (our US term for earthing) - however, 40 years ago, the standard was only 2 wires -and cheap adaters exist at hardware stores that accept 3 pins on one side and connect to the wall with 2 on the other - perhape something like this exists in Belgium? (However, let me state I don't know you're power system, you should consult with someone locally about the ramification of doing this - preferably your rotel dealer)
- Jack

[soundhound]

While it would eliminate ground loops (allowing line frequency to be audible) by putting a chasis ground pin on every component, this common ground scheme also allows other frequencies (various noise) to enter into circuits where manufactures don't want them. By isolating circuits a certain amount of ammunity can be had. Here in the states our neutral line is grounded, so for safety sake there is an earth ground @ the panel.

[NewBuyer]

soundhound, you mention that in the US our neutral line is grounded. I'm naively wondering, does this mean that the third pin (ground) is completely unnecessary/useless?

[csuzor]

Asterduc, did this extra earth connection remove the static discharge problem on the face of your RSX-1056? for me it is usually minor, but running my fingers slowly over the rotel gear causes small static discharges, quite unpleasant (I shouldnt caress the gear, I know... i just like it so much!). Actually I sometimes get a significant static discharge, quite annoying, others have this problem... maybe adding a simple earth wire to the chassis helps?
Thanks
Christophe

[soundhound]

Newbuyer, it will normally go in and tie right to a chasis, it's redundant in that respect but not useless. If you look at 2 prong 110 plugs, they are polarized, the wide blade is neutral, now look at a 3 prong plug, both hot and neutral plugs are identicle, they have a dedicated ground so there is no need to polarize. This is all in reference to a complete device (amp/pre/dvd/etc...) at the end of the cord because a.c is constantly changing polarity, thus alternating current. If this comes off a little babbley, bear with me, our grandaughter spent the night last night, (4 1/2) I am on my 1st cup of coffee, so......

[Asterduc]

Thanks guys for the reply,

@basementjack, soundhound, newbuyer:
Our Neutral and Ground are also on the same level. This means the Neutral is grounded too, measured voltage between Neutral and Ground is 0 volt. However it makes a huge difference if you connect the Ground wire.

@csuzor: I had some static loading (or shall I say Unloadingà before the Ground was connected. That is now history. If I now touch finger the front panel there is not tension at all, this was different when I had not connected the Ground wire.

Ed.

[csuzor]

DO IT ! Ground the Rotel !

Thanks again Asterduc for your post, I just grounded my RSP1068... no more static or electric discharge, I could even kiss it, nothing!

Note that none of my gear has an earth connection (2 rotel, 1 denon dvd, 1 satellite receiver, 1 sony TV), so I was planning to ground them all... but since they are plugged into the same multi-plug board, and each to the RSP, grounding just the RSP removed the static/ electric problem from all the others as well!

It was nice to see, I connected the plug first (just 1 wire to the ground pin, so no risk), then unscrewed a screw on the RSP, and the moment it touches the RSP I see small sparks... that was energy going to me before, much better that it goes to "mother earth".

Finally, and almost as important, that annoying hiss from the speakers in standby is significantly reduced.


I have to say this, don't laugh:
Legal disclaimer:
Be careful not to connect to a live pin.
Do not attempt to modify or add any electrical connection if you are not a certified practicing eletrician or equivalent.
No responsibility accepted for any damage whatsoever.