Impact of using a NAD C298 amplifier without the “NAD-required” grounding

[Louis]

Hello,

I consider to add a NAD C298 to my Marantz SR7011 receiver in favor of the front speakers, hoping that that will be a significant and audible upgrade to the system. There are a couple of thinks holding me back for the moment, it is an additional box, some doubt if it is really audible and of course it is costing money.

However .... , there is one more issue, the issue which did me decide to start this thread. That is this warning in the NAD manual:

“WARNING For optimal performance, the C298 requires a grounded AC receptacle or a separate earth ground. Ensure the proper grounding of your system.”

And yep that is probably a good idea. However I do not have “earth ground” in my living room and it is not so easy to create one as well.
So my question is to share your experiences about / related to, a “not grounded C298".

Sincerely,

Louis

 

[JeffS7444]

I consider to add a NAD C298 to my Marantz SR7011 receiver in favor of the front speakers, hoping that that will be a significant and audible upgrade to the system.

Probably not much audible difference, if any: Although the NAD C298 likely measures much better, the Marantz nevertheless is probably good enough that it will sound pretty much the same as long as you do not exceed it's rated power limits. Remember that test instruments are far more sensitive than human hearing!

 

[wwenze]

Err...

Does your socket have 3 pins?

 

[Louis]

I assume you refer to to electric power socket, no in my living room it does not have a ground pin. That is the problem.

Perhaps I should rephrase my question a bit different:

"Is there any one out there using a C298 without earth ground and is that causing any kind of problems?"

If so in which way?

Louis

 

[restorer-john]

However I do not have “earth ground” in my living room and it is not so easy to create one as well.

All your power points will have a proper earth ground connection. If they don't, then you have serious safety issues with your wiring...

 

[Louis]

No! Here in the Netherlands we only have earth ground in wet rooms. All other rooms like bedrooms, living rooms etc, do have power outlets without earth ground. And that is perfectly save!

 

[restorer-john]

No! Here in the Netherlands we only have earth ground in wet rooms. All other rooms like bedrooms, living rooms etc, do have power outlets without earth ground. And that is perfectly save!

Well you learn something every day. I figured you'd have the normal earthed ones like these, all through a typical house:

They really need to move into last century and have polarised (non-rotatable) fittings too.

 

[Koeitje]

Well you learn something every day. I figured you'd have the normal earthed ones like these, all through a typical house:

View attachment 132039

They really need to move into last century and have polarised (non-rotatable) fittings too.

It depends on when the house was built, all modern (1990+?) houses and apartments have grounded outlets. Every home also has a RCD of course, regardless of all the sockets being grounded.

Anyway, how does polarity even matter? Its AC, and unless you do something that isn't allowed its perfectly safe also.

 

[jensgk]

No! Here in the Netherlands we only have earth ground in wet rooms. All other rooms like bedrooms, living rooms etc, do have power outlets without earth ground. And that is perfectly save!

Same here in Denmark. We have very high safety standards here.

EDIT: I have just check the current safety standards, and apparently all new installations since 1994 must have ground... We don't, since our house is from 1969...

These are the typical power outlets:

 

[wwenze]

It depends on when the house was built, all modern (1990+?) houses and apartments have grounded outlets. Every home also has a RCD of course, regardless of all the sockets being grounded.

Anyway, how does polarity even matter? Its AC, and unless you do something that isn't allowed its perfectly safe also.

Polarity matters a lot for safety.

The center pin of a lightbulb is live while the screw part of the socket is neutral. Imagine polarity reversal.

Also, the fuse is usually only on the live side for good reason. If the fuse is on the neutral side and it blows, the rest of the circuit will be charged to live AC level, and won't know it because there is no current flowing... until you touch it.

 

[AdamG]

No! Here in the Netherlands we only have earth ground in wet rooms. All other rooms like bedrooms, living rooms etc, do have power outlets without earth ground. And that is perfectly save!

Welcome Aboard @Louis.

 

[Koeitje]

Polarity matters a lot for safety.

The center pin of a lightbulb is live while the screw part of the socket is neutral. Imagine polarity reversal.

Also, the fuse is usually only on the live side for good reason. If the fuse is on the neutral side and it blows, the rest of the circuit will be charged to live AC level, and won't know it because there is no current flowing... until you touch it.

Literally all of my lamps have euro plugs so those are all unsafe to use I guess.

Naturally all the wiring in the house is done while keeping live and neutral in mind (they are of course color coded also), but for regular sockets it really doesn't matter.

 

[wwenze]

Literally all of my lamps have euro plugs so those are all unsafe to use I guess.

Naturally all the wiring in the house is done while keeping live and neutral in mind (they are of course color coded also), but for regular sockets it really doesn't matter.

 

[Koeitje]

If I plug in my euro plug and I can still jab my finger right into centerpin of where the light bulb goes. So it is clearly unsafe to use these plugs according to your logic.

 

[wwenze]

If I plug in my euro plug and I can still jab my finger right into centerpin of where the light bulb goes. So it is clearly unsafe to use these plugs according to your logic.

Then your lamp is not class II. And yes you're right that is not safe.

 

[Koeitje]

Then your lamp is not class II. And yes you're right that is not safe.

Time to sue Ikea.

 

[elgeeko]

I wouldn't worry about it. Unlike a lot of solid-state amplifiers, the NAD c298 floats its outputs with respect to ground. It specifically indicates you should not ground the negative terminals, while many other amps will internally wire to ground.

There's a safety issue about safe failure due to a short-circuit, but from an audio perspective it won't matter.

 

[restorer-john]

Anyway, how does polarity even matter? Its AC, and unless you do something that isn't allowed its perfectly safe also.

Polarity serioiusly matters.

The system is multiple earthed neutral (MEN) here and is similar in most countries. That means the neutral is tied to ground at most poles (with a cable running down the pole into the earth) and is also tied to earth at the distribution panel. The neutral is tied to ground at that point too.

Much gear only has single pole switching of the active. If you rotate the plug, you are only switching the neutral instead of the active. Such gear is technically and practically live with no return to netral/ground in an off state.

In short (no pun intended), it is dangerous to have an easily rotatable mains plug.