Grounding question and Airmotiv 4

[shellylh]

I got the Airmotiv 4 today and they sound great.  They are also so small!  However, I have a safety concern that I wanted to ask about.  

 

First, they are not grounded but have a metal plate in back.  This concerns me - seems dangerous. I know there is a lot of electronic equipment that is not grounded but I would guess that having the metal in back and using high voltage (I assume it is high voltage) would require a ground.  It uses a 3 prong cord but there is no connection to the ground.

 

Here is a picture of the IEC inlet.

 

 

Second (and this is the weird thing), the manual clearly says the following.  Why would they say that if the ground was connected to nothing. 

 

p.9 Quick Start: 

• Plug your airmotiv powered studio monitors into grounded AC electrical outlets. If 

you use a different power cord or extension cord, use only a three-prong grounded 

type. 

 

p. 20 Operation: 

• Plug your airmotiv powered studio monitors into a grounded electrical outlet of 

appropriate voltage. (Verify that your airmotiv powered studio monitors are the 

correct models for your local AC line voltage. The correct line voltage is shown on 

the rear panel.)

 

p. 29 under Safety Instructions:

Always connect your airmotiv powered monitor to a properly grounded outlet which 

supplies the correct voltage, using either the supplied power cord or an equivalent 

replacement. The airmotiv powered monitor draws very little power, and you may 

safely use a longer replacement cord or extension cord if desired. 

(If so, always use a three-prong grounded type.) 

 

http://emotiva.com/resources/manuals/airmotiv4_manual.pdf

 

I am happy with the very speakers but would want definitely send them back if there is any safety concerns.  It's just not worth the worry and risk to me. 

 

Perhaps someone can explain what might be going on here.  I guess Colin has a pair so maybe he can explain things to me.

 

Edit:  I found a picture of the inside of the Airmotiv 5 (don't know if this is similar to Airmotiv 4).  It also doesn't seem to have a ground connection (see second picture). 

 

 

Edited November 15, 2013 by shellylh

[grawk]

Mine's the same.  I'm guessing it's to make sure the polarity is in the correct direction, but they don't want noise coming in through the ground.  It's not a lot of power, and it is a fused outlet...

[mikeymad]

My 5 (before I sent it back) also no ground. 

[shellylh]

Ok, I can understand the reason for using a 3 prong plug with no ground (for polarity reasons or maybe because it is more structurally sound) and understand not wanting to introduce ground loops but I don't understand why they go on and on saying that one must use a grounded outlet... also, I still don't see why it is safe, especially with the metal plate in back and the metal screws. 

[grawk]

A lot of the world uses ungrounded outlets, it's just a matter of properly designing the equipment.  

 

They say you must use a grounded outlet because it's easier than explaining outlet polarity, and better mechanical connections, etc.  Basically, saving on customer service complaints.  Also, the people that wrote the manual probably never met the people that designed the amplifier.

[n_maher]

I wouldn't stress/worry about it, Shelly.  There are probably 1,000 other things in your house far more likely to kill you than these and a high percentage of those aren't worth a second thought either.  If Emotiva thought there was 0.01% chance these would kill you by grounding AC to the back plate and that a third prong would fix it they would have done it.  My guess is that they've mitigated that risk through other means.

[blessingx]

Probably best to focus on the two dozen things in your house most likely to kill you tonight.

[grawk]

start with the hubby

[mikeymad]

haha

[shellylh]

Haha, when I was asking hubby about this, he told me I need to get some drugs.  

 

When Nate said that I immediately started thinking of all the things in my house that are probably less than perfectly safe... maybe I do need some drugs, at least a drink.  

Edited November 15, 2013 by shellylh

[nikongod]

At the risk of returning this to a serious discussion, there are ways of double-insulating (as indicated {if you believe it} by the 2 squares next to the CE mark - on the lower left of the panel) the chassis of a device so that if a mains wire were to come loose there is no danger of the user getting zapped. They do add expense to the whole mess, but I guess Emotiva thought the expense was worth an added layer of ground loop resistance. 

 

The note to use a 3-prong plug could be a leftover from generic instructions. Who actually wants to write instructions on how to plug something in? Much easier to just copy it from something else without even proof-reading it. 

[screaming oranges]

Hubbies don't kill if you ground them first.

[Dusty Chalk]

The note to use a 3-prong plug could be a leftover from generic instructions. Who actually wants to write instructions on how to plug something in? Much easier to just copy it from something else without even proof-reading it. 

That was my theory.

[shellylh]

Who actually wants to write instructions on how to plug something in? Much easier to just copy it from something else without even proof-reading it.

 

 

 

At the risk of returning this to a serious discussion, there are ways of double-insulating (as indicated {if you believe it} by the 2 squares next to the CE mark - on the lower left of the panel) the chassis of a device so that if a mains wire were to come loose there is no danger of the user getting zapped. They do add expense to the whole mess, but I guess Emotiva thought the expense was worth an added layer of ground loop resistance. 

 

The note to use a 3-prong plug could be a leftover from generic instructions. Who actually wants to write instructions on how to plug something in? Much easier to just copy it from something else without even proof-reading it.

 

Hmm, I guess I'll just have to decide if they are lying about the CE certification or not I guess.  The thing that worries me is that Emotiva buys these from a Chinese company and rebrands them (adding a warranty and supposedly a CE certification).  I just don't trust that the random Chinese company would do something that costs more.  

 

Edit:  Here is what the president of Emotiva said

 

"QMS is the local market brand name of their manufacturing partner in China. Emotiva developed a version of this monitor product for their exclusive use under the Emotiva Pro brand. It was a brand new project for QMS, and they had already opened some of the tooling. Emotiva loved the look, so they purchased rights to use it, and they have exclusivity for the USA. 

Also, please note that the Emotiva units are voiced quite a bit differently and subject to a completely different quality standard than the locally produced versions, as Emotiva's QC standards are very high. Also, the prices shown for QMS are for local market China sale. A consumer trying to buy these in China to import them to the USA while paying duties, confirming that the China made variant is RoHS compliant and will even be allowed to enter the USA, would be cost prohibitive and very difficult. Then, what does the consumer do if it breaks? Send it back to China to some trading company? 

What they do with variants of this product in their local China market is out of Emotiva's control. 

Remember, Emotiva buys them by the thousands, literally! Emotiva certifies them for safety compliance, ships them to the USA, pays freight, duty, and customs fees. Emotiva does incoming quality testing, etc. They then ship them to you FREE with a 30 day in home trial, and back it with a 5 years parts and labor warranty. This is something you can't get by buying a variant from China."

 

So it seems like Emotiva might have designed these after all.

Edited November 15, 2013 by shellylh